[RSM] W3LPL prop forecast 2021 03 16

[Art Boyars]

From: donovanf at erols.com
To: pvrc reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 16 Mar 2021 01:47:44 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be normal through Wednesday

Long distance propagation forecast for Tuesday and Wednesday, March 16-17

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 normal on Tuesday, then normal on 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 75 though at

least Wednesday. There is only one tiny sunspot on the visible disk

having no significant effect on HF propagation.



We are in the March-April geomagnetic storm season when the earth

passes through the part of the interplanetary magnetic field (IMF)

with more frequent, longer 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 through 17 meter low and mid latitude propagation is likely to be

normal through Wednesday.



160 and 80 meter short path propagation to south Asia is likely to be

normal at 0200Z Wednesday. 80 meter short path propagation from

North America to east Asia is likely to be mostly normal on Tuesday

then normal on Wednesday. 80, 40 and 30 meter long path propagation

from North America to southeast Asia at about 2330Z is likely to be

normal through Wednesday.



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

normal on Tuesday then normal on 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 one tiny sunspot on the visible

disk.



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

mostly normal on Tuesday then normal on Wednesday. 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 one tiny sunspot 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 one tiny sunspot 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 decline to quiescent

levels through Wednesday. Earth directed CMEs or solar flares strong

enough to affect HF propagation are not likely through Wednesday.



Northern hemisphere daylength is 153 minutes longer than it was on

December 21st. Sunset is now 91 minutes later than it was on

December 9th. Daylength is increasing by two minutes per day which

is steadily reducing the duration of common darkness between distant

locations in the northern hemisphere.



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 and hamqsl.com/solar.html
<http://www.hamqsl.com/solar.html>