[RSM] W3LPL prop forecast Fri/19 - Sun/21

[Art Boyars]

From: donovanf at erols.com
To: pvrc reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Fri, 19 Mar 2021 00:33:23 -0400 (EDT)
Subject: [PVRC] Normal propagation until late Friday then below normal this
weekend

Long distance propagation forecast for Friday through Sunday, March 19-21

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 Sunday. Mid-latitude propagation is likely to be normal

until late Friday then mostly normal through Sunday. Auroral

zone and polar propagation is likely to be mostly normal until

late Friday then degraded to below normal through 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 remain at about 72

though at least Sunday. There is only one sunspot region

on the visible disk with only two small 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 the

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 Sunday.

80 meter short path propagation from North America to

east Asia is likely to be normal on Friday then below normal

on Saturday and Sunday. 80, 40 and 30 meter long path

propagation from North America to southeast Asia at about

2330Z is likely to be below normal through Sunday.



30 meter auroral zone and polar propagation is likely to be

mostly normal until late Friday then degraded to below

normal through 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 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

small sunspots on the visible disk.



20 meter daytime auroral zone and polar propagation is

likely to be mostly normal until late Friday then degraded

to below normal through Sunday. 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 small 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 small

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 quiescent levels through late Friday when earth directed coronal

hole high speed stream enhancements in the solar wind are likely

to produce disturbed geomagnetic activity through Sunday. There

is a possibility of minor geomagnetic storm conditions late Saturday

through early Sunday. Earth directed CMEs or solar flares strong

enough to affect HF propagation are not likely through Sunday.



Northern hemisphere daylength is 161 minutes longer than it was on

December 21st. Sunset is now 94 minutes later than it was on

December 9th. The equinox arrives early Saturday when the sun crosses

the celestial equator. 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


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