W3LPL Propagation forecast

[4L5A]

Propagation crossing all latitudes is likely to be normal through Sunday.



40 and 30 meter DX propagation is likely from early evening until after sunrise.

20, 17 and 15 meter DX propagation is likely 24 hours per day.

12 meter DX propagation is likely from early morning until late night.

10 meter DX propagation is likely from mid-morning through evening hours.


This 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.



Global 6 meter F2 propagation may begin by late October if solar flux values continue to persist well above 200. 6 meter Trans-Equatorial F2 Propagation (TEP) is likely to occur regularly from the southern tier of US states from September through November. More northerly locations need an additional sporadic-E or F2 hop. 6 meter sporadic-E propagation beyond 2200 km is extremely unlikely until December.



The 2300Z Penticton 10.7 cm observed solar flux index was 233 and is likely to remain about the same through Sunday.


SILSO’s latest Estimated International Sunspot Number was 192 and is likely to remain about the same through Sunday.

The visible solar disk has one growing large active region, one stable large region, two growing medium active regions, one stable medium active region, one growing small active region, two stable small active regions, and one stable very small active region containing 75 sunspots with a total sunspot area of 2240 micro solar hemispheres (about ten times the surface area of the Earth).

Solar wind speed is likely to be 400 km/second or less through at least Sunday.



Quiet geomagnetic conditions are likely 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 X-class solar flares may cause about an hour of widespread blackouts of propagation paths crossing the sunlit side of the Earth through Sunday.

No S1-class or stronger solar radiation storms are expected 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 normal through Sunday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Sunday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be 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 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 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 normal through Sunday.



12 and 10 meter propagation is likely to be 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 normal through Sunday.



Thermally driven high velocity seasonal 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 high latitudes to mostly less than 28 MHz through about mid-September.



Brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation is extremely unlikely from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. 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) is extremely unlikely from about 1400-1800Z. F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America is extremely unlikely from about 2000-0200Z. 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, VP6 and ZL) is extremely unlikely from about 1900-0300Z. It is extremely unlikely that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. There is a chance of TEP propagation 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 45 minutes later and sunset is 45 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]

This 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.



Global 6 meter F2 propagation may begin by late October if solar flux values continue to persist well above 200. 6 meter Trans-Equatorial F2 Propagation (TEP) is likely to occur regularly from September through November. 6 meter sporadic-E propagation beyond 2200 km is extremely unlikely until December.



The 2300Z Penticton 10.7 cm observed solar flux index was 240 and is likely to remain about the same through Saturday.

SILSO’s latest Estimated International Sunspot Number was 230 and is likely to remain about the same through Saturday.

The visible solar disk has one growing large active region, one stable large region, two growing medium active regions, one stable medium active region, two stable small active regions, one decaying small active region and two decaying very small active regions containing 90 sunspots with a total sunspot area of 2240 micro solar hemispheres (about 13 times the surface area of the Earth).

Solar wind speed is likely to be about 400 km/second or less through at least Saturday.



Mostly quiet geomagnetic conditions are likely through Saturday.


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 X-class solar flares 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 that S1-class solar radiation storms may cause brief, minor degradation of propagation crossing the northern hemisphere polar region through Saturday.

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 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 normal through Saturday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Saturday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be normal through 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 normal through 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 normal through 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 normal through Saturday.



12 and 10 meter propagation is likely to be normal through 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 normal through Saturday.



Thermally driven high velocity seasonal 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 high latitudes to mostly less than 28 MHz through about mid-September.



Brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation is extremely unlikely from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. 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) is extremely unlikely from about 1400-1800Z. F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America is extremely unlikely from about 2000-0200Z. 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, VP6 and ZL) is extremely unlikely from about 1900-0300Z. It is extremely unlikely that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. There is a chance of TEP propagation 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 43 minutes later and sunset is 42 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]

Some of the best summer solar maximum propagation of Solar Cycle 25 is likely through at least Friday.



Propagation crossing all latitudes is likely to be normal through Friday.



40 and 30 meter DX propagation is likely from early evening until after sunrise.

20, 17 and 15 meter DX propagation is likely 24 hours per day.

12 meter DX propagation is likely from early morning until late night.

10 meter DX propagation is likely from mid-morning through evening hours.


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



Global 6 meter F2 propagation may begin by late October. Sporadically occurring 6 meter Trans-Equatorial F2 Propagation (TEP) is likely from September through November. 6 meter sporadic-E propagation beyond 2200 km is extremely unlikely until December.



The 2300Z Penticton 10.7 cm observed solar flux index was 237 and is likely to remain about the same through Friday.


SILSO’s latest Estimated International Sunspot Number was 238 and is likely to remain about the same through Friday.

The visible solar disk has three growing large active regions, two growing medium active regions, one decaying medium active region, one growing small active region, two stable small active regions and two decaying small active regions containing 90 sunspots with a total sunspot area of 2240 micro solar hemispheres (about 13 times the surface area of the Earth).

Solar wind speed is likely to be about 400 km/second or less through at least Friday.



Quiet geomagnetic conditions are likely Wednesday.

Quiet to unsettled geomagnetic conditions are likely on Thursday.

Mostly quiet geomagnetic conditions are likely 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 X-class solar flares 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 brief, 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 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 normal through Friday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Friday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be normal through 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 through 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 normal through 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 through Friday.



12 and 10 meter propagation is likely to be normal through 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 through Friday.



Thermally driven high velocity seasonal 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 high latitudes to mostly less than 28 MHz through about mid-September.



Brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation is extremely unlikely from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. 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) is extremely unlikely from about 1400-1800Z. F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America is extremely unlikely from about 2000-0200Z. 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, VP6 and ZL) is extremely unlikely from about 1900-0300Z. It is extremely unlikely that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. There is a chance of TEP propagation 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 42 minutes later and sunset is 40 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]

Propagation crossing all latitudes is likely to be normal through Thursday.



40 and 30 meter DX propagation is likely from early evening until after sunrise.

20, 17 and 15 meter DX propagation is likely 24 hours per day.

12 meter DX propagation is likely from early morning until late night.

10 meter DX propagation is likely from mid-morning through evening hours.


This 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.



Global 6 meter F2 propagation is likely to begin by late October. Sporadically occurring 6 meter trans-equatorial F2 propagation (TEP) is likely from September through November. 6 meter sporadic-E propagation beyond 2200 km is extremely unlikely until December.



The 2300Z Penticton 10.7 cm observed solar flux index was 241 and is likely to remain about the same through Thursday.


SILSO’s latest Estimated International Sunspot Number was 227 and is likely to remain about the same through Thursday.

The visible solar disk has three growing large active regions, two growing medium active regions, one decaying medium active regio, two growing small active regions and two stable small active regions containing 103 sunspots with a total sunspot area of 2240 micro solar hemispheres (about 13 times the surface area of the Earth).

The visible solar disk has three growing large active regions, two growing medium active regions, one decaying medium active regio, two growing small active regions and two stable small active regions containing 103 sunspots with a total sunspot area of 2240 micro solar hemispheres (about 13 times the surface area of the Earth).

Solar wind speed is likely to be about 400 km/second or less through at least Thursday.



Quiet geomagnetic conditions are likely through Wednesday.

Mostly quiet geomagnetic conditions are likely on Thursday.


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 chance that X-class solar flares 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 brief, 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 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 normal through Thursday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Thursday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be normal 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 normal 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 normal 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 normal through Thursday.



12 and 10 meter propagation is likely to be normal 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 normal through Thursday.



Thermally driven high velocity seasonal 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 high latitudes to mostly less than 28 MHz through about mid-September.



Brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation is extremely unlikely from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. 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) is extremely unlikely from about 1400-1800Z. F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America is extremely unlikely from about 2000-0200Z. 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, VP6 and ZL) is extremely unlikely from about 1900-0300Z. It is extremely unlikely that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. There is a chance of TEP propagation 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 41 minutes later and sunset is 38 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]

Some of the best summer solar maximum propagation of Solar Cycle 25 is likely through at least Wednesday



Propagation crossing all latitudes is likely to be normal through Wednesday.




40 and 30 meter DX propagation is likely from early evening through after sunrise,

20, 17 and 15 meter DX propagation is likely 24 hours per day.

12 meter DX propagation is likely from early morning until late night.

10 meter DX propagation is likely from mid-morning through evening hours.


This 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.



Global 6 meter F2 propagation is likely during about half of the days each month beginning in late October. 6 meter trans-equatorial F2 propagation (TEP) is likely from late September through November. 6 meter sporadic-E propagation beyond 2200 km is extremely unlikely until December.



The 2300Z Penticton 10.7 cm observed solar flux index was 233 and is likely to remain about the same through Wednesday.


SILSO’s latest Estimated International Sunspot Number was 209 and is likely to remain about the same through Wednesday.

The visible solar disk has one growing large active region, three growing medium active regions, one decaying medium active region, three growing small active regions, one stable small active region and one stable very small active region containing 70 sunspots with a total sunspot area of 1640 micro solar hemispheres (about ten times the surface area of the Earth).

Solar wind speed is likely to be about 400 km/second or less through at least Wednesday.



Quiet geomagnetic conditions are likely through Wednesday.


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 Wednesday. There is a chance that X-class solar flares 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 brief, minor degradation of propagation crossing the northern hemisphere polar region through Wednesday.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be normal through Wednesday . 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 normal through Wednesday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Wednesday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be normal through 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 Wednesday. 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 normal through 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 Wednesday.



12 and 10 meter propagation is likely to be normal through 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 Wednesday.



Thermally driven high velocity seasonal 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 late August and mostly less than 28 MHz through mid-September. 12 meter MUFs are usually not significantly depressed during August when the solar flux index exceeds about 200. 10 meter MUFs are usually not significantly depressed from August through mid-September when the solar flux index exceeds about 250.



Brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation is extremely unlikely from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. 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) is extremely unlikely from about 1400-1800Z. F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America is extremely unlikely from about 2000-0200Z. 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, VP6 and ZL) is extremely unlikely from about 1900-0300Z. It is extremely unlikely that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. There is a chance of TEP propagation 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 40 minutes later and sunset is 37 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 rapidly waning northern hemisphere 6 meter sporadic-E season is extremely unlikely to produce sporadic-E propagation beyond 2200 km until December.



The 2300Z Penticton 10.7 cm observed solar flux index was 245 and is likely to remain about the same through Saturday.

SILSO’s latest Estimated International Sunspot Number was 177 and is likely to remain about the same through Saturday.

The visible solar disk has one growing very large active region, one decaying very large active region, one decaying medium active region, three decaying small active regions, two stable very small active regions and one decaying very small active region containing 94 sunspots with a total sunspot area of 2250 micro solar hemispheres (about 13 times the surface area of the Earth).

Solar wind speed is likely to be about 400 km/second or less through Saturday.



Mostly quiet geomagnetic conditions are likely through 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 Saturday. There is a chance that X-class solar flares 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 that S1-class solar radiation storms may cause brief, minor degradation of propagation crossing the northern hemisphere polar region through Saturday.

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 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 Saturday. Short path propagation between North America and east Asia after about 0930Z is likely to be mostly normal through Saturday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through 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 mostly normal through 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 mostly normal through 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 on Thursday, improving to normal through Saturday.



12 and 10 meter propagation is likely to be mostly normal through 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 on Thursday, improving to normal through Saturday.



Thermally driven high velocity seasonal 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 late August and mostly less than 28 MHz through mid-September. 12 meter MUFs are usually not significantly depressed during August when the solar flux index exceeds about 200. 10 meter MUFs are usually not significantly depressed from August through mid-September when the solar flux index exceeds about 250.



Brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation is extremely unlikely from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. 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) is extremely unlikely from about 1400-1800Z. F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America is extremely unlikely from about 2000-0200Z. 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, VP6 and ZL) is extremely unlikely from about 1900-0300Z. It is extremely unlikely that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. There is a chance of TEP propagation 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 38 minutes later and sunset is 34 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 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.



The rapidly waning northern hemisphere 6 meter sporadic-E season is extremely unlikely to produce sporadic-E propagation beyond 2200 km until December.



The 2300Z Penticton 10.7 cm observed solar flux index was 2658 and is likely to remain about the same through Friday.

SILSO’s latest Estimated International Sunspot Number was 218 and is likely to remain about the same through Friday.

The visible solar disk has one growing very large active region, one growing large active region, one growing medium active region, two decaying medium active regions, one growing small active region, one decaying small active regions, one growing very small active region, one stable very small active region and one decaying very small active region containing 99 sunspots with a total sunspot area of 2410 micro solar hemispheres (about 15 times the surface area of the Earth).


Solar wind speed is likely to be about 450 km/second or less through midday Wednesday, then declining to about 400 km/second or less through Friday.



Unsettled to active geomagnetic conditions are likely through midday Wednesday, improving to quiet conditions through late Thursday and mostly quiet conditions 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 X-class solar flares 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 brief, 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 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 mostly normal through Friday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through 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 mostly normal through 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 mostly normal through 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 be mostly normal through 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 seasonal 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 late August and mostly less than 28 MHz through mid-September. 12 meter MUFs are usually not significantly depressed during August when the solar flux index exceeds about 200. 10 meter MUFs are usually not significantly depressed from August through mid-September when the solar flux index exceeds about 250.



Brief, isolated, geographically focused 6 meter trans-Atlantic sporadic-E propagation is extremely unlikely from about 1100-2200Z between mid-latitude U.S states and Europe, North Africa and the Middle East. 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) is extremely unlikely from about 1400-1800Z. F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states to South America is extremely unlikely from about 2000-0200Z. 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, VP6 and ZL) is extremely unlikely from about 1900-0300Z. It is extremely unlikely that more northerly U.S. stations may couple into TEP and oblique-TEP via geographically focused brief intervals of sporadic-E propagation. There is a chance of TEP propagation 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 37 minutes later and sunset is 33 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 Monday August 12th 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.



The rapidly waning northern hemisphere 6 meter sporadic-E season is very unlikely to produce long distance sporadic-E propagation beyond 2200 km this week.



The 2300Z Penticton 10.7 cm observed solar flux index was 275 and is likely to remain about the same through Wednesday.

SILSO’s latest Estimated International Sunspot Number was 242 and is likely to remain about the same through Wednesday.

The visible solar disk has one decaying very large active region, two growing large active regions, one growing medium active region, three decaying medium active regions, and four decaying very small active regions containing 84 sunspots with a total sunspot area of 2500 micro solar hemispheres (about 15 times the surface area of the Earth).

Solar wind speed is likely to be about 500 km/second through late Monday, declining to about 450 km/second through Tuesday then gradually declining to about 400 km/second on Wednesday.



Mostly active geomagnetic conditions with a possible isolated weak geomagnetic storm are likely through Monday. Mostly unsettled to active geomagnetic activity is likely on Tuesday and mostly quiet geomagnetic conditions are likely on Wednesday.


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 Wednesday. There is a chance that X-class solar flares 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 brief, minor degradation of propagation crossing the northern hemisphere polar region through Wednesday.

160 and 80 meter propagation from North America to VK/ZL and the South Pacific is likely to be mostly normal on Monday improving to normal through Wednesday . 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 Tuesday and mostly normal on Wednesday. Short path propagation between North America and east Asia after about 0930Z is likely to be moderately degraded on Monday, mildly degraded on Tuesday and mostly normal on Wednesday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be moderately degraded on Monday, improving to mildly degraded on Tuesday and mostly normal on 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 moderately degraded on Monday, improving to mildly degraded on Tuesday and mostly normal on Wednesday. 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 Monday, improving to mildly degraded on Tuesday and mostly normal on 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 mildly degraded on Monday and mostly normal on Tuesday and Wednesday.



12 and 10 meter propagation is likely to be moderately degraded on Monday, improving to mildly degraded on Tuesday and mostly normal on 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 mildly degraded on Monday and mostly normal on Tuesday and Wednesday.



Thermally driven high velocity seasonal 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. F2 MUFs affecting 12 and 10 meter propagation are usually not significantly depressed during August and September when the solar flux index exceeds about 200.



There is very little 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 little 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 little 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 little 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, VP6 and ZL) from about 1900-0300Z. There is a very little 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 36 minutes later and sunset is 31 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]

Ain't this solar maximum great?

Solar Cycle 25 is now much, much stronger than anyone anticipated, and its slowly growing stronger through at least this weekend.
Today's [Wednesday] estimated international sunspot number is 281.


Its increasingly likely that we'll have widespread coast-to-coast and worldwide 6 meter F2 propagation during about half of the days between late October and at least early February. Widespread F2 openings are likely to bring 6 meter CW and SSB to life like we haven't experienced in more than 20 years.

The first sign of enhanced 6 meter F2 will be increasingly frequent TEP from Europe and North America to South America and the South Atlantic islands. TEP may begin very sporadically by late August and become increasingly frequent later in September and especially during October.

Coast-to-coast F2 propagation and propagation crossing the Atlantic to Europe and Africa may begin sporadically during September and October and become frequent and long lasting by early November.

Effective 6 meter antennas can be very small. 3 element Yagis are small,
lightweight and very effective. 20 foot antenna height is adequate but sloping terrain or higher antennas perform much better. Heights higher that 50 feet are un necessary and in many cases perform poorly.

Are you ready for this once in a lifetime experience?

73
Frank
W3LPL

[4L5A]

The Thursday August 8th 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 only a very slight chance that the rapidly waning northern hemisphere 6 meter sporadic-E season may produce very brief geographically focused sporadic-E long distance propagation beyond 2200 km during this week. Solar maximum effects are causing much less frequent, much shorter duration and much 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 294 and is likely to remain about the same through at least Saturday.



Solar wind speed is likely to be about 400 km/second or less through midday Friday, rapidly increasing to well above 500 km/second after midday Friday and gradually declining to about 400 km/second by late Saturday.



Geomagnetic activity is likely to mostly quiet through midday Friday.

Minor to moderate geomagnetic storms are likely from midday Friday through midday Saturday, then gradually improving to mostly active through 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 Saturday. There is a chance that X-class solar flares 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 that S1-class solar radiation storms may cause minor degradation of propagation crossing the northern hemisphere polar region through Saturday.

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 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 normal through Saturday. Short path propagation between North America and east Asia after about 0930Z is likely to be normal through Saturday.


30 meter propagation crossing the auroral ovals and polar regions is likely to be mostly normal through midday Friday, then moderately degraded through midday Saturday, then gradually improving to mostly normal through late 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 mostly normal through midday Friday, then moderately degraded through midday Saturday, then gradually improving to mostly normal through late 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 mostly normal through midday Friday, then moderately degraded through midday Saturday, then gradually improving to mostly normal through late 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 normal on Thursday, mostly normal on Friday and mildly disturbed on Saturday.



12 and 10 meter propagation is likely to be normal mostly normal through midday Friday, then moderately degraded through midday Saturday, then gradually improving to mostly normal through late 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 normal on Thursday, mostly normal on Friday and mildly disturbed on Saturday.



Thermally driven high velocity seasonal 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, VP6 and ZL) 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 33 minutes later and sunset is 27 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.