[RSM] W3LPL prop forecast Tue-Wed Mar 23-24

[Art Boyars]

From: donovanf at erols.com
To: pvrc reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 23 Mar 2021 01:24:37 -0400 (EDT)
Subject: [PVRC] Mostly Normal Propagation through Wednesday

Long distance propagation forecast for Tuesday and Wednesday March 23-24

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

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



Low and mid-latitude propagation is likely to be normal through

at least Wednesday. Auroral zone and polar propagation is likely

to be mostly below normal through Wednesday.



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 78 though

at least Wednesday. 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 from North America to

VK/ZL is likely to be normal through Wednesday. 160 and 80 meter

short path propagation to south Asia at about 0200Z is likely to be

below normal through Wednesday. 80 meter short path propagation

from North America to east Asia is likely to be below normal through

Wednesday. 80, 40 and 30 meter long path propagation from North

America to southeast Asia at about 2300Z is likely to be below normal

through Wednesday.



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

normal through Wednesday. 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 Wednesday. 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 Wednesday due to waning coronal hole

high speed stream effects in the solar wind. 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 Wednesday.



Mid latitude northern hemisphere sunset is now 3 minutes later and

daylength is 8 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. 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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