[RSM] W3LPL forecast Fri-Sat

[Art Boyars]

From: donovanf at erols.com
To: PVRC List <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Fri, 14 May 2021 01:38:24 -0400 (EDT)
Subject: [PVRC] Normal Propagation likely through late Saturday gradually
degrading the mostly normal on Sunday

Long distance propagation forecast for Friday through Sunday May 14-16



My propagation forecast derived from today's NOAA/SWPC web

pages is published five days a week (M-F) in the Daily DX.



Low latitude propagation is likely to be normal through Sunday.

Mid-latitude propagation in likely to be normal through late Saturday

then mostly normal through Sunday. Propagation through the auroral

oval and polar regions is likely to be normal through late Saturday

then degrading to mostly below normal on Sunday.



Click *here* <https://services.swpc.noaa.gov/images/planetary-k-index.gif>
for today’s
latest planetary Kp Index, updated every three hours.

Click *here* <http://www.hamqsl.com/solar.html> for N0NBH’s current HF Band
Conditions, updated regularly.



The solar flux index (SFI) is likely to be about 75 through Sunday.

There are two active regions on the visible disk with 7 small and

tiny sunspots having a minor effect on HF propagation.



160 and 80 meter short path propagation from North America to

VK/ZL and the south Pacific is likely to be normal through Sunday.

40 meter short path propagation to south Asia is likely to be normal

at about 0015Z Saturday and mostly normal at about 0015Z Sunday.

40 meter short path propagation from North America to east Asia

after about 0930Z is likely to be normal through Saturday then

gradually degrading to mostly below normal on Sunday.



30 meter propagation through the auroral ovals and polar regions

is likely to be likely to be normal through late Saturday then

gradually degrading to mostly below normal on Sunday. 30 meter

propagation is always significantly degraded within a few hours

of local noon because of E-region blanketing of long distance F2

propagation. 30 meter night time propagation in the northern

hemisphere is likely to improve slightly due to minor sunspot

influence and longer daylight duration.



20 meter daytime and evening propagation through the auroral ovals

and polar regions is likely to be normal through late Saturday then

gradually degrading to mostly below normal on Sunday. 20 meter

northern transpolar propagation within a few hours of sunrise and

sunset will steadily improve with gradually increasing electron

density in the polar F2 region through June. 20 meter night time

long distance propagation in the northern hemisphere is likely

to improve slightly due to minor sunspot influence and longer

daylight duration.



17 and 15 meter daytime long distance propagation in the northern

hemisphere is likely to improve slightly due to minor sunspot

influence and longer daylight duration. 12 and 10 meter daytime

long distance propagation is likely to be mostly unreliable and

mostly limited to propagation from North America to Southern

Africa, South Atlantic, South America and South Pacific regions.



Geomagnetic disturbances *caused by coronal hole high speed*

*streams* are likely to remain mostly brief, minor and less frequent

through at least late 2021. The north-south (Bz) component of the

IMF plays a *crucial role* in triggering all geomagnetic storms.

Brief minor to moderate geomagnetic storms may be gradually

triggered when Bz persists in a southward orientation (-Bz)

with enhanced IMF field strength for several hours *coincident*

*with* the effects of an earth directed *coronal hole high speed*

*stream*. More frequent, longer duration, minor to severe

geomagnetic storms may be triggered *suddenly* when Bz persists

in a southward orientation (-Bz) with enhanced IMF field strength

for several hours or more *coincident with* the effects of an

earth directed CME.



IMF field strength, solar wind speed near earth and geomagnetic

activity are likely to be nominal through late Saturday then

gradually degrading to slightly enhanced levels on Sunday.

Geomagnetic storms, earth directed coronal hole high speed streams

and solar flares strong enough to affect HF propagation are

not likely through Sunday.



Mid latitude northern hemisphere sunset is now 54 minutes later

and daylength is 129 minutes longer than it was on the March 20th.

Daylength is increasing by two minutes per day which is steadily

lengthening the duration of common daylight between distant

locations in the northern hemisphere. The elevation angle of the

midnight sun in the northern polar region is increasing about three

degrees per week, steadily improving 20 meter northern trans-polar

propagation through June.



Click *here* <https://www.spaceweather.gc.ca/solarflux/sx-4-en.php> for today’s
Penticton 10.7 cm solar flux index updated at 1700Z, 2000Z and 2300Z daily.

Click *here*
<https://spaceweather.gfz-potsdam.de/fileadmin/ruggero/Kp_forecast/forecast_figures/KP_FORECAST_CURRENT.png>
for today’s
three-day GFZ Planetary K Index forecast updated every three hours.

Click *here* <http://sidc.oma.be/products/meu/> for today's SIDC Daily
Bulletin on Solar and Geomagnetic Activity updated at 1230Z daily.

Click *here* <https://www.swpc.noaa.gov/products/forecast-discussion>
for today's
SWPC Solar Activity Forecast Discussion updated at 0030Z and 1230Z daily.

Click *here* <https://www.sws.bom.gov.au/Space_Weather/1/1> for today's
Australian Space Forecast Centre Summary and Forecast updated at 2330Z
daily.



Perhaps the most useful HF propagation pages for DXers can be found at:

http://dx.qsl.net/propagation and http://www.solarham.net

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