[RSM] W3LPL: back to normal early Thursday

[Art Boyars]

From: donovanf at erols.com
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 13 Oct 2021 01:06:55 -0400 (EDT)
Subject: [PVRC] Propagation is likely to gradually improve after mid-day
Wednesday, returning to normal by early Thursday October 14th 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 and mid-latitudes, the auroral ovals and polar
regions is likely to be below normal until mid day Wednesday then gradually
improving to normal by early Thursday.

 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 82 through Thursday.
The sun’s visible disk has one small and one mid-size active region with
six small to mid-size sunspots.
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 mostly below normal through mid day Wednesday then
gradually improving to normal by early Thursday. 40 meter short path
propagation to south Asia at about 0000Z is likely to be mostly normal
through Thursday. 40 meter short path propagation from North America to
east Asia after about 0830Z is likely to be mostly below normal on
Wednesday and mostly normal on Thursday.

 30 meter propagation through the auroral ovals and polar regions is likely
to be mostly below normal until mid day Wednesday then gradually improving
to mostly normal by early Thursday. 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 nighttime long
distance propagation is likely to be enhanced by increased residual
nighttime ionization caused by increased sunspot activity but gradually
waning CME effects are likely to degrade propagation to mostly below normal
through mid-day Wednesday then gradually improving to mostly normal by
early Thursday,

 20 meter daytime and evening propagation through the auroral ovals and
polar regions is likely to be mostly below normal until mid day Wednesday
then gradually improving to mostly normal by early Thursday. 20 meter
transpolar propagation within a few hours of sunrise and sunset is likely
to be mostly normal through late Thursday. 20 meter late afternoon,
nighttime and early morning long distance propagation is likely to be
enhanced by increased residual nighttime ionization caused by increased
sunspot activity but gradually waning CME effects are likely to degrade
propagation to mostly below normal through mid-day Wednesday then gradually
improving to mostly normal by early Thursday.

 17, 15 and occasional 12 meter daytime long distance and autumnal equinox
long path propagation is likely to be enhanced by increased sunspot
activity but gradually waning CME effects are likely to degrade propagation to
mostly below normal through mid-day Wednesday then gradually improving to
mostly normal by early Thursday. 17 and 15 meters are open for long
distance and long path propagation nearly every day due to increased solar
activity and the effects of the autumnal equinox. 12 meter long distance
and long path propagation is steadily improving but is not as reliable as
15 meters. North American stations should look for Asian long path on
17, 15 and
12 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 gradually decline from moderate levels after
mid-day Wednesday reaching ambient background levels by early Thursday.

 The geomagnetic field is likely to be mostly unsettled until mid-day
Wednesday due to gradually waning CME effects and gradually improving to
mostly quiet levels by early Thursday. Geomagnetic storms, coronal high
speed stream effects and solar flare effects strong enough to significantly
degrade HF propagation are not likely through Thursday.

 Mid-latitude northern hemisphere sunset is 32 minutes earlier and
daylength is 52 minutes shorter than it was on September 22nd. Daytime
ionization and residual nighttime ionization in the northern polar region
is steadily declining following the autumnal equinox.

 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