[RSM] (Decision time) W3LPL prop forcast for Mon-Tue

Mon Mar 22 10:35:58 EDT 2021

Decision time -- are enough RSM Reflector subscribers interested in this to
warrant my continuing to post on the Reflector?  If there is not enough
general interest, I could, perhaps, just forward it to interested
individuals. OR...

Note the last paragraph, where Frank suggests a source he says is
"[p]erhaps the most useful HF propagation pages for DXers.... "  OR...

Note also that the forecast is published M-F in the Daily DX.

73, Art K3KU/VE4VTR
======================

From: donovanf at erols.com
To: pvrc reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Mon, 22 Mar 2021 01:40:17 -0400 (EDT)
Subject: [PVRC] Mostly below normal propagation through Tuesday

Long distance propagation forecast for Monday and Tuesday, March 22-23

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 at least

Tuesday. Mid-latitude propagation is likely to be mostly normal

through Tuesday. Auroral zone and polar propagation is likely to be

mostly below normal through Tuesday.

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 remain at about 77 though at

least Tuesday. There is only one sunspot region on the visible disk

with only two tiny sunspots having no significant effect on HF

propagation.

We are in the most disturbed weeks of the March-April geomagnetic

storm season when the earth passes through the part of the interplanetary

magnetic field (IMF) with most frequent, longest duration southward

oriented magnetic field. Approximately twice as many brief minor and

moderate geomagnetic storms occur during March and April compared

to the quieter IMF during June and July. Brief minor to moderate

geomagnetic storms may be triggered with little warning when the IMF

rotates to a southward orientation and persists for several hours

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

stream enhancements in the solar wind.

160 and 80 meter short path propagation to south Asia at about 0200Z

is likely to be below normal through Tuesday. 80 meter short path

propagation from North America to east Asia is likely to be below

normal through Tuesday. 80, 40 and 30 meter long path propagation

from North America to southeast Asia at about 2300Z is likely to be

below normal through Tuesday.

30 meter auroral zone and polar propagation is likely to be below

normal through Tuesday. 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 propagation is

unreliable during most of the night in the northern hemisphere

because of insufficient residual night time F region electron density

due to only two tiny sunspots on the visible disk.

20 meter daytime auroral zone and polar propagation is likely to be

below normal through Tuesday. 20 meter northern hemisphere

trans-polar propagation within a few hours of sunrise and sunset will

gradually improve with increased electron density in the polar cap

F2 region through June. Night time 20 meter propagation in the

northern hemisphere continues to be very unreliable because of

insufficient residual F region electron density due to only two tiny

sunspots on the visible disk.

17 and 15 meter daytime mid-latitude propagation in the northern

hemisphere continues to be shorter in duration because of insufficient

F2 region electron density due to only two tiny sunspots on the visible

disk. 12 and 10 meter daytime propagation is likely to be unreliable

and mostly limited to propagation from North America to Southern

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

Active geomagnetic conditions *caused by coronal hole high speed*

*streams* are likely to remain mostly brief, minor and relatively

infrequent through at least late 2021. Brief minor to moderate

geomagnetic storms may be triggered when the IMF persists in a

southward orientation (-Bz) with enhanced field strength for several

hours *coincident with* the effects of earth directed coronal hole

high speed stream enhancements in the solar wind.

IMF field strength, solar wind speed near earth, coronal hole high

speed stream effects and geomagnetic activity are likely to remain

at enhanced levels through Tuesday due to waning coronal hole

high speed stream effects in the solar wind. There is a possibility

of isolated minor geomagnetic storm conditions for several hours

after Monday local midnight. There is a chance of a glancing blow

from a coronal mass ejection (CME) late Tuesday. Solar flares

strong enough to affect HF propagation are not likely through Tuesday.

Mid latitude northern hemisphere sunset is now 2 minutes later than

it was on March 20th. Daylength is 5 minutes longer than it was on

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. Daylength at far northern

polar latitudes is increasing by 30 minutes per day and will reach

24 hours of daylight on April 7th, significantly improving 20 meter

trans-polar propagation.

Click *here* <https://www.spaceweather.gc.ca/solarflux/sx-4-en.php> for today’s
Penticton 10.7 cm solar flux index updated at 1800Z, 2000Z and 2200Z 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:

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

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