[RSM] W3LPL forecast thru early Fri/22

[Art Boyars]

From: donovanf at erols.com
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 21 Oct 2021 00:44:49 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation with possible mildly to
moderately degraded intervals through early Friday October 22nd

My propagation forecast derived from today's NOAA/SWPC web pages
is published five days a week (M-F) in the Daily DX.

 Propagation crossing low latitudes is likely to be normal through Friday.

 Propagation crossing mid latitudes is likely to be mostly normal through
Friday.

 Propagation crossing the auroral ovals and polar regions is likely to be
mostly normal through Friday with possible mildly to moderately disturbed
intervals through early Friday when the solar wind returns to background
levels and coronal hole high speed stream effects fade.

 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.

 We are in the geomagnetically active autumn equinox season through late
October with about twice as many geomagnetically active days compared to
December, January, June and July caused by the interplanetary magnetic
field (IMF) more frequently persisting in a southward orientation (-Bz).

 The solar flux index (SFI) is likely to be at least 76 through Friday.
There is one moderate sized sunspot on the visible disk.
https://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0171.jpg

 160 and 80 meter propagation from North America to VK/ZL and the south
Pacific is likely to be normal through Friday. 40 meter short path
propagation to south Asia at about 0000Z is likely to be mostly normal with
possible below normal intervals through early Friday. 40 meter short path
propagation from North America to east Asia after about 0830Z is likely to
be mostly normal with possible below normal intervals through early Friday.

 30 meter propagation through the auroral ovals and polar regions is likely
to mostly normal with possible below normal intervals through early Friday. 30
meter propagation is always significantly degraded within a few hours of
local noon because of E-region blanketing of long distance F2 propagation.

 20 meter daytime and evening propagation through the auroral ovals and
polar regions is likely to be mostly normal with possible below normal
intervals through early Friday. 20 meter transpolar propagation within a
few hours of sunrise and sunset is likely to be mostly normal with possible
below normal intervals through early Friday.

 17 and 15 meters are open for long distance and long path propagation nearly
every day due to the effects of the autumnal equinox. North American
stations should look for Asian long path on 17 and 15 meters starting a few
hours after sunrise and persisting for at least several hours.

 Geomagnetic disturbances *caused by coronal hole high speed stream*
effects are likely to remain mostly brief, minor and somewhat less frequent
through at least late 2021. The southward oriented (-Bz) component of the
interplanetary magnetic field (IMF) plays a *crucial but unpredictable role* in
triggering all geomagnetic storms. Brief minor to moderate geomagnetic
storms may be gradually triggered when the IMF 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* *and unpredictably *when the IMF persists in a
southward orientation (-Bz) with enhanced IMF field strength for several
hours or more *coincident with* the effects of an Earth directed fast CME.

 The solar wind is likely to be mildly to moderately enhanced through early
Friday when the solar wind returns to background levels and coronal hole
high speed stream effects fade.

 The geomagnetic field is likely to be quiet to unsettled through Friday
with possible active intervals through early Friday due to isolated coronal
hole high speed stream effects. Geomagnetic storms, coronal mass ejections
and solar flare effects strong enough to significantly degrade HF
propagation are not likely through Friday.

 Mid-latitude northern hemisphere sunset is 43 minutes earlier and
daylength is 72 minutes shorter than it was on September 22nd. Daytime
ionization and residual nighttime ionization in the north polar region
continues to steadily decline as we approach the end of the autumnal
equinox season.

 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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