W3LPL Propagation forecast

[4L5A]

Geomagnetic storms and active geomagnetic conditions are about half as likely through mid-July compared to their more frequent occurrence during the equinox seasons.



Although we are in the prime northern hemisphere 6 meter sporadic-E season through mid-July, solar maximum effects are causing less frequent and shorter duration long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and continued through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 209 and is likely to remain about the same through Saturday.

SILSO’s latest Estimated International Sunspot Number was 272 and is likely to remain about the same through Saturday.

The visible solar disk has one large, three medium, nine small and four very small active regions containing 105 sunspots with a total sunspot area of 1190 micro solar hemispheres (about seven times the surface area of the Earth).

M-class solar flares are likely to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Saturday. There is a slight chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Saturday.

There is a slight chance of S1-class minor solar radiation storms through Saturday with minimal impact on propagation crossing polar regions.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be normal through Saturday . 160 and 80 meter long distance propagation from June through September in the northern hemisphere is always mildly to moderately degraded by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to be mostly normal through Saturday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Friday and mostly normal on Saturday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through Saturday with possible mild degradation during local nighttime hours. Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through Saturday with possible mild degradation during local nighttime hours. 20 meter long distance propagation in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through Saturday with possible mild degradation during local nighttime hours. 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal through Saturday .



12 and 10 meter propagation is likely to be mostly normal through Saturday with possible mild degradation during local nighttime hours. 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal through Saturday .



Thermally driven high velocity thermospheric winds at the F2 region altitude blow from the high temperature dayside hemisphere to the low temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to less than 24 MHz through mid-September and less than 28 MHz through late September.



There is a slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 14 minutes later and sunset seven minutes later than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the absorbing D region.

[4L5A]

Geomagnetic storms and active geomagnetic conditions are about half as likely through mid-July compared to their more frequent occurrence during the equinox seasons.



After mid-July, northern hemisphere 6 meter sporadic-E season produces transatlantic sporadic-E about half as often as during learly July. Solar maximum effects are also causing less frequent and shorter duration long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and continued through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 210 and is likely to remain about the same through Sunday.

SILSO’s latest Estimated International Sunspot Number was 284 and is likely to remain about the same through Sunday.

The visible solar disk has one very large, three medium, eight small and six very small active regions containing 97 sunspots with a total sunspot area of 1230 micro solar hemispheres (about seven times the surface area of the Earth).

Solar wind speed is likely to be mostly near background levels of less than 400 km/second until about midday Saturday, mildly increasing to greater than 400 km/second from midday Saturday through late Sunday.



Geomagnetic activity is likely to be mostly quiet with unsettled intervals until about midday Saturday, degrading to mostly unsettled to active from midday Saturday through late Sunday. An isolated weak geomagnetic storm is likely early Sunday.


M-class solar flares are likely to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Sunday. There is a slight chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Sunday.

There is a slight chance of S1-class minor solar radiation storms through Sunday with minimal impact on propagation crossing polar regions.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be normal through Sunday . 160 and 80 meter long distance propagation from June through September in the northern hemisphere is always mildly to moderately degraded by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to be mostly normal through Saturday There is a chance of the propagation crossing mid-latudes mat suffer degradation at early Sunday.. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Saturday and mostly normal on Sunday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through Sunday with possible mild degradation during local nighttime hours. Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through Sunday with possible mild degradation during local nighttime hours. 20 meter long distance propagation in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through Sunday with possible mild degradation during local nighttime hours. 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal through Sunday .



12 and 10 meter propagation is likely to be mostly normal through Sunday with possible mild degradation during local nighttime hours. 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal with possible mild degradation on Sunday.



Thermally driven high velocity thermospheric winds at the F2 region altitude blow from the high temperature dayside hemisphere to the low temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 16 minutes later and sunset is nine minutes later than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the absorbing D region.

[4L5A]

Geomagnetic storms and active geomagnetic conditions are about half as likely through at least mid-July compared to their more frequent occurrences during the equinox seasons.



The northern hemisphere 6 meter sporadic-E season is may produce transatlantic sporadic-E during only a few days in late July. Solar maximum effects are also causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 199 and is likely to remain about the same through Wednesday.

SILSO’s latest Estimated International Sunspot Number was 179 and is likely to remain about the same through Wednesday.

The visible solar disk has two large, three medium, three small and four very small active regions containing 80 sunspots with a total sunspot area of 1360 micro solar hemispheres (about eight times the surface area of the Earth).

Solar wind speed is likely to be mostly near ambient levels of less than 350 km/second through at least Tuesday, with a chance of a mild increase to greater than 400 km/second during Wednesday.



Geomagnetic activity is likely to be quiet through at least Tuesday, with a chance that it may degrade to mostly unsettled to active during Wednesday due to a chance of CME arrival. There is a chance of a minor geomagnetic storm on Wednesday due to a chance of CME arrival.

M-class solar flares are likely to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Wednesday. There is a slight chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Wednesday.

There is a slight chance of S1-class minor solar radiation storms through Wednesday with minimal impact on propagation crossing polar regions.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be normal through Tuesday with a chance of mild degradation during Wednesday . 160 and 80 meter long distance propagation from June through September in the northern hemisphere is always mildly to moderately degraded by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to be normal through Wednesday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Tuesday with a chance of mild degradation on Wednesday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be normal through Tuesday with a chance of mild degradation during Wednesday . Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be normal through Tuesday with a chance of mild degradation during Wednesday . 20 meter long distance propagation in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be normal through Tuesday with a chance of mild degradation during Wednesday . 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be normal through Tuesday with a chance of mild degradation on Wednesday



12 and 10 meter propagation is likely to normal through Tuesday with a chance of mild degradation during Wednesday . 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be normal through Tuesday with a chance of mild degradation on Wednesday



Thermally driven high velocity thermospheric winds at the F2 region altitude blow from the high temperature dayside hemisphere to the low temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 18 minutes later and sunset is nine minutes later than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the absorbing D region.

[4L5A]

The declining northern hemisphere 6 meter sporadic-E season may produce occasional brief isolated transatlantic sporadic-E openings during the last week in July. Solar maximum effects are causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 184 and is likely to remain about the same through Thursday.

SILSO’s latest Estimated International Sunspot Number was 181 and is likely to remain about the same through Thursday.

Solar wind speed is likely to be near ambient levels of less than 350 km/second through Wednesday, mildly to moderately increasing to greater than 400 km/second during Thursday, and gradually declining to below 400 km/second by late Thursday.



Geomagnetic activity is likely to be mostly quiet through Wednesday. A minor to moderate geomagnetic storm is likely on Wednesday due to CME arrival.

M-class solar flares are likely to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Thursday. There is a slight chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Thursday.

There is a slight chance of S1-class minor solar radiation storms through Thursday with minimal impact on propagation crossing polar regions.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be normal through Thursday . 160 and 80 meter long distance propagation in the northern hemisphere is always mildly to moderately degraded through September by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to mildly degraded through Thursday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal on Tuesday, moderately degraded on Wednesday and mostly normal on Friday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be normal on Tuesday, moderately degraded on Wednesday then gradually improving to mostly normal during Thursday . Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be normal on Tuesday, moderately degraded on Wednesday then gradually improving to mostly normal during Thursday . 20 meter long distance propagation in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be normal on Tuesday, moderately degraded on Wednesday then gradually improving to mostly normal during Thursday . 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be normal on Tuesday, moderately degraded on Wednesday improving to mostly normal on Thursday.



12 and 10 meter propagation is likely to normal on Tuesday, moderately degraded on Wednesday and mostly normal on Thursday . 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be normal on Tuesday, moderately degraded on Wednesday improving to mostly normal on Thursday.

Thermally driven high velocity thermospheric winds at F2 region altitude blow from the high temperature dayside hemisphere to the lower temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very slight chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 19 minutes later and sunset is ten minutes earlier than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the absorbing D region.

[4L5A]

The waning northern hemisphere 6 meter sporadic-E season may produce occasional brief geographically focused transatlantic sporadic-E openings during the last seven days of July. Solar maximum effects are causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 174 and is likely to remain about the same through Friday.

SILSO’s latest Estimated International Sunspot Number was 174 and is likely to remain about the same through Friday.

The visible solar disk has one large, four medium, two small and three very small active regions containing 67 sunspots with a total sunspot area of 1175 micro solar hemispheres (about seven times the surface area of the Earth).



Solar wind speed is likely to be near ambient levels of less than 350 km/second through Wednesday, mildly increasing to greater than 400 km/second during Thursday, and declining to less than 400 km/second on Friday.



Geomagnetic activity is likely to be mostly quiet on Wednesday, quiet to unsettled on Thursday improving to quiet on Friday


M-class solar flares are likely to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Friday. There is a slight chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Friday.

There is a slight chance of S1-class minor solar radiation storms through Friday with minimal impact on propagation crossing polar regions.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be normal through Friday . 160 and 80 meter long distance propagation in the northern hemisphere is always mildly to moderately degraded through September by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to mostly normal on Thursday, then improving to normal on Friday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal on Wednesday, mostly normal on Thursday, then improving to normal on Friday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be normal on Wednesday, mostly normal on Thursday, then improving to normal on Friday. Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be normal on Wednesday, mostly normal on Thursday, then improving to normal on Friday. 20 meter long distance propagation in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be normal on Wednesday, mostly normal on Thursday, then improving to normal on Friday. 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be normal on Wednesday, mostly normal on Thursday, then improving to normal on Friday



12 and 10 meter propagation is likely to normal on Wednesday, mostly normal on Thursday, improving to normal on Friday. 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be normal on Wednesday, mostly normal on Thursday, then improving to normal on Friday .



Thermally driven high velocity thermospheric winds at F2 region altitude blow from the high temperature dayside hemisphere to the lower temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very slight chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 20 minutes later and sunset is 11 minutes earlier than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the absorbing D region.

[4L5A]

There is a slight chance that the rapidly waning northern hemisphere 6 meter sporadic-E season may produce a brief geographically focused transatlantic sporadic-E opening before the end of July. Solar maximum effects are causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 166 and is likely to remain about the same through Sunday.

SILSO’s latest Estimated International Sunspot Number was 189 and is likely to remain about the same through Sunday.

The visible solar disk has two medium, six small and three very small active regions containing 61 sunspots with a total sunspot area of 730 micro solar hemispheres (about four times the surface area of the Earth).

Solar wind speed is likely to be elevated at levels of about 450 km/second or more through midday Saturday, then gradually improving to about 400 km/second or less through Sunday.



Minor geomagnetic storms are likely through midday Saturday. Geomagnetic activity is likely to improve to mostly quiet to unsettled through Sunday.

M-class solar flares are likely to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Sunday. There is a slight chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Sunday.

There is a slight chance that S1-class solar radiation storms may cause minor degradation of propagation crossing the northern hemisphere polar region through Sunday.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be normal through Sunday . 160 and 80 meter long distance propagation in the northern hemisphere is always mildly to moderately degraded through September by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to be mildly degraded on Saturday and mostly normal on Sunday. Short path propagation between North America and east Asia after about 0930Z is likely to be mildly degraded through Saturday and mostly normal on Sunday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to moderately disturbed through midday Saturday, gradually improving to

mostly normal through Sunday. Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to moderately disturbed through midday Saturday, gradually improving to

mostly normal through Sunday. 20 meter propagation beyond 2200 km in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to moderately disturbed through midday Saturday, gradually improving to mostly normal through Sunday. 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mildly to moderately degraded through midday Saturday improving to mostly normal on Sunday.



12 and 10 meter propagation is likely to be mildly to moderately disturbed through midday Saturday, gradually improving to mostly normal through Sunday. 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mildly to moderately degraded through midday Saturday improving to mostly normal on Sunday.



Thermally driven high velocity thermospheric winds at F2 region altitude blow from the high temperature dayside hemisphere to the lower temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a very slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very slight chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 22 minutes later and sunset is 14 minutes earlier than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the daytime absorbing D region.

[4L5A]

There is a very slight chance that the rapidly waning northern hemisphere 6 meter sporadic-E season may produce a brief geographically focused transatlantic sporadic-E opening before the end of July. Solar maximum effects are causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 210 and is likely to remain about the same through Wednesday

SILSO’s latest Estimated International Sunspot Number was 208 and is likely to remain about the same through Wednesday.

The visible solar disk has two large, seven medium and one very small active region containing 89 sunspots with a total sunspot area of 1920 micro solar hemispheres (about 11 times the surface area of the Earth).

Solar wind speed is likely to be at 400 km/second or less through about midday Monday. The arrival of multiple CMEs is likely to solar wind speed to 450 km/second or more by late Monday continuing through midday Wednesday, then gradually improving to about 400 km/second or less through late Wednesday.



Mostly quiet to unsettled geomagnetic activity is likely through midday Monday. Active geomagnetic activity is likely from midday through late Monday. Minor geomagnetic storms are expected from late Monday through midday Wednesday. Moderate geomagnetic storms are likely from before midday Tuesday through early Wednesday. There is a chance of strong geomagnetic storms from midday through late Tuesday. Geomagnetic activity is likely to improve to mostly unsettled to active from midday through late Wednesday.


M-class solar flares are likely to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Wednesday. There is a slight chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Wednesday.

There is a slight chance that S1-class solar radiation storms may cause minor degradation of propagation crossing the northern hemisphere polar region through Wednesday.

There is a very slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very slight chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 24 minutes later and sunset is 16 minutes earlier than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the daytime absorbing D region.

[4L5A]

There is a very slight chance that the rapidly waning northern hemisphere 6 meter sporadic-E season may produce a brief geographically focused transatlantic sporadic-E opening this week. Solar maximum effects are causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 218 and is likely to remain about the same through Thursday.

SILSO’s latest Estimated International Sunspot Number was 217 and is likely to remain about the same through Thursday.

The visible solar disk has one large, six medium, two small and one very small active region containing 110 sunspots with a total sunspot area of 1720 micro solar hemispheres (about ten times the surface area of the Earth).

The arrival of as many as seven CMEs is likely to maintain the solar wind speed at up to 450 km/second or more through at least midday Thursday, then gradually improving to about 400 km/second or less through late Thursday.



Minor to strong geomagnetic storms are expected during Tuesday. Minor to moderate geomagnetic storms are likely from early through midday Wednesday. There is a chance of strong geomagnetic storms from midday through late Wednesday. Unsettled to active geomagnetic conditions are likely early Thursday. Minor to moderate geomagnetic storms are likely during midday Thursday. Geomagnetic activity is likely to improve to mostly unsettled to active from midday through late Thursday.

M-class solar flares are expected to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Thursday. There is a chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Thursday.

There is a slight chance that S1-class solar radiation storms may cause minor degradation of propagation crossing the northern hemisphere polar region through Thursday.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be mostly normal through Thursday . 160 and 80 meter long distance propagation in the northern hemisphere is always mildly to moderately degraded through September by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to be moderately to strongly degraded on Wednesday and mildly to moderately degraded on Thursday. Short path propagation between North America and east Asia after about 0930Z is likely to be strongly to moderately degraded on Tuesday and mildly to moderately degraded on Wednesday and Thursday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to strongly degraded through Thursday. Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to strongly degraded through Thursday. 20 meter propagation beyond 2200 km in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to strongly degraded through Thursday. 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be moderately to strongly degraded through Thursday.



12 and 10 meter propagation is likely to be mildly to strongly degraded through Thursday. 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be moderately to strongly degraded through Thursday.



Thermally driven high velocity thermospheric winds at F2 region altitude blow from the high temperature dayside hemisphere to the lower temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a very slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very slight chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 25 minutes later and sunset is 17 minutes earlier than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the daytime absorbing D region.

[4L5A]

The Wednesday July 31st W3LPL propagation forecast derived from today 's NOAA/SWPC web pages and 15 other online sources (the URLs at the end of this forecast) is published five days a week (M-F) in The Daily DX .

All days and times in this forecast are in UTC (Zulu) time.



There is a very slight chance that the rapidly waning northern hemisphere 6 meter sporadic-E season may produce a brief geographically focused transatlantic sporadic-E opening before Friday. Solar maximum effects are causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 222 and is likely to remain about the same through Friday.


SILSO’s latest Estimated International Sunspot Number was 249 and is likely to remain about the same through Friday.

The visible solar disk has one large, six medium, two small and one very small active region containing 141 sunspots with a total sunspot area of 1910 micro solar hemispheres (about 11 times the surface area of the Earth).

The arrival of as many as seven CMEs is likely to maintain the solar wind speed at up to 450 km/second or more through at least late Thursday, then gradually improving to about 400 km/second or less through late Friday.



Minor to moderate geomagnetic storms likely with a chance of a strong storm from late Wednesday through midday Thursday. Unsettled to active geomagnetic conditions are likely from midday Thursday through early Friday. Geomagnetic activity is likely to improve to mostly quiet from before midday through late Friday.


M-class solar flares are expected to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Friday. There is a chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Friday

There is a slight chance that S1-class solar radiation storms may cause minor degradation of propagation crossing the northern hemisphere polar region through Friday.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be mostly normal through Friday . 160 and 80 meter long distance propagation in the northern hemisphere is always mildly to moderately degraded through September by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to be mostly normal through Friday. Short path propagation between North America and east Asia after about 0930Z is likely to be mildly to moderately degraded on Wednesday and Thursday and mostly normal on Friday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to moderately degraded through midday Thursday, gradually improving to mildly degraded through early Friday and further improving to mostly normal before midday Friday. Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to moderately degraded through midday Thursday, gradually improving to mildly degraded through early Friday and further improving to mostly normal before midday Friday. 20 meter propagation beyond 2200 km in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be mildly to moderately degraded through midday Thursday, gradually improving to mildly degraded through early Friday and further improving to mostly normal before midday Friday. 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal through Friday.



12 and 10 meter propagation is likely to mildly to moderately degraded through midday Thursday, gradually improving to mildly degraded through early Friday and further improving to mostly normal before midday Friday. 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal through Friday.



Thermally driven high velocity thermospheric winds at F2 region altitude blow from the high temperature dayside hemisphere to the lower temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a very slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very slight chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 26 minutes later and sunset is 18 minutes earlier than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the daytime absorbing D region.

[4L5A]

There is only a very slight chance that the rapidly waning northern hemisphere 6 meter sporadic-E season may produce a brief geographically focused transatlantic sporadic-E opening by Saturday. Solar maximum effects are causing less frequent, shorter duration and less reliable long distance sporadic-E propagation beyond 2200 km than occurred during solar minimum and through 2022.



The 2300Z Penticton 10.7 cm observed solar flux index was 238 and is likely to remain about the same through Saturday.

SILSO’s latest Estimated International Sunspot Number was 257 and is likely to remain about the same through Saturday.

The visible solar disk has three large, five medium, four small and one very small active region containing 141 sunspots with a total sunspot area of 2540 micro solar hemispheres (about 15 times the surface area of the Earth).

Persistent CME effects are likely to maintain the solar wind speed at up to 450 km/second or more through at least early Friday, then slowly improving to about 400 km/second or less through late Saturday.



Minor to moderate geomagnetic storms are likely with a chance of a strong storm through late Thursday. Unsettled to active geomagnetic conditions are likely from early through midday Friday. Geomagnetic activity is then likely to improve to mostly quiet through at late Saturday.


M-class solar flares are expected to cause a few minutes of minor to moderate radio blackouts of propagation paths crossing the sunlit side of the Earth through Friday. There is a chance that an X-class solar flare may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Friday.

There is a chance that S1-class solar radiation storms may cause minor degradation of propagation crossing the northern hemisphere polar region through Friday.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be mostly normal on Thursday improving to normal through Saturday . 160 and 80 meter long distance propagation in the northern hemisphere is always mildly to moderately degraded through September by E region blanketing of low angle F2 propagation until at least several hours after sunset.



40 meter short path propagation from North America to the Middle East and south Asia after 0030Z is likely to be mostly normal on Friday and normal on Saturday. Short path propagation between North America and east Asia after about 0930Z is likely to be mostly normal on Thursday improving to normal on Saturday and Sunday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be moderately degraded on Thursday, improving to mostly normal on Friday and normal on Saturday. Daytime 30 meter long distance propagation is always mildly to moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely to be moderately degraded on Thursday, improving to mostly normal on Friday and normal on Saturday. 20 meter propagation beyond 2200 km in the northern hemisphere from June through September is always moderately degraded within several hours of local noon by E-region blanketing of low angle F2 propagation.


17 and 15 meter propagation crossing the auroral ovals and polar regions is likely to be moderately degraded on Thursday, improving to mostly normal on Friday and normal on Saturday. 17 and 15 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal through Friday improving to normal on Sunday.



12 and 10 meter propagation is likely to be moderately degraded on Thursday, improving to mostly normal on Friday and normal on Saturday. 12 and 10 meter long path propagation from North America to southeast and east Asia from about 1100Z to 1400Z is likely to be mostly normal through Friday improving to normal on Sunday



Thermally driven high velocity thermospheric winds at F2 region altitude blow from the high temperature dayside hemisphere to the lower temperature nightside hemisphere reducing the volume of neutral atomic oxygen available to be ionized in the F2 region during daytime hours, lowering the MUF for F2 propagation crossing the northern hemisphere to mostly less than 24 MHz through mid-September and mostly less than 28 MHz through late September.



There is a very slight chance of brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. There is a very slight chance of brief geographically focused 6 meter F2 propagation enhanced by TEP over Africa from the southern tier of US states to the Indian Ocean, equatorial and southern Africa (e.g., 3B8. 3B9, 7Q, D2, FR, V5, ZD7 and ZS) from about 1400-1800Z. There is a very slight chance of F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America from about 2000-0200Z. There is a very slight chance of above-the-MUF oblique-TEP F2 propagation from the southern tier of US states to the south Pacific (e.g., 3D2, 5W, E5, FK, FO, VK4, VK9, VP6, ZL and ZL7) from about 1900-0300Z. There is a very slight chance that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. TEP may be significantly enhanced from about 2000-0200Z during the initial phase of strong to severe geomagnetic storms then degrading several hours after initial enhancement.

Sustained southward orientation (-Bz) of the north-south component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic

storms may be gradually triggered when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for at least a few hours coincident with the influence of a geoeffective coronal hole high speed stream or CME. More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF is sustained in a southward orientation (-Bz) with IMF field strength of about 5 nanoteslas or more for a period of several hours or more coincident with the influence of a geoeffective CME and solar wind speed of about 500 km/second or more.



Mid-latitude northern hemisphere sunrise is 27 minutes later and sunset is 19 minutes earlier than it was on June 20th . Sunrise is about two hours earlier and sunset is about two hours later at the altitude of the refracting F2 region. Sunrise is about one hour earlier, and sunset is about one hour later at the altitude of the daytime absorbing D region.