[RSM] W3LPL: Improving to mostly normal after mid-day Tuesday/28

[Art Boyars]

From: donovanf at erols.com
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Mon, 27 Sep 2021 02:13:20 -0400 (EDT)
Subject: [PVRC] Below normal propagation likely Monday slowly improving to
mostly normal after mid-day Tuesday September 28th 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 mostly below normal on
Monday improving to normal on Tuesday.

 Propagation crossing mid latitudes is likely to be below normal on Monday
and improving to mostly normal after mid-day Tuesday

 Propagation crossing the auroral ovals and polar regions is likely to be
below normal on Monday and improving to mostly normal with below normal
intervals after mid-day Tuesday.

 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).
https://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0171.jpg

 The solar flux index (SFI) is likely to be about 86 through Tuesday. The
sun’s visible disk has four small active regions containing 28 small and
tiny sunspots.

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

 30 meter propagation through the auroral ovals and polar regions is likely
to be below normal on Monday and improving to mostly normal with below
normal intervals after mid-day Tuesday. 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 below normal on
Monday and improving to mostly normal with below normal intervals after
mid-day Tuesday due to increased geomagnetic activity.

 20 meter daytime and evening propagation through the auroral ovals and
polar regions is likely to be below normal on Monday and improving to
mostly normal with below normal intervals after mid-day Tuesday. 20 meter
transpolar propagation within a few hours of sunrise and sunset is likely
to be below normal on Monday and improving to mostly normal with below
normal intervals after mid-day Tuesday. 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 below normal on Monday than improving to mostly normal with
below normal intervals after mid-day Tuesday due to increased geomagnetic
activity.

 17, 15 and occasional 12 meter daytime long distance propagation is likely
to be enhanced by increased sunspot activity but below normal on Monday
then improving to mostly normal with below normal intervals after mid-day
Tuesday due to increased geomagnetic activity.

 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.

 Solar wind speed is likely to be moderately enhanced on Monday due to
coronal hole high speed stream (CH HSS) and CME effects and less enhanced
wind speed after mid-day Tuesday due to waning CH HSS and CME effects.

 The geomagnetic field (GMF) is likely to be at active to moderate (G2)
storm levels on Monday due to coronal hole high speed stream effects and a
possible glancing blow CME then slowly improving to mostly quiet after
mid-day Tuesday. A moderate geomagnetic (G2) storm is possible on Monday
with a chance of a brief minor geomagnetic (G1) storm on Tuesday if the IMF
persists in a southward orientation (-Bz). Solar flare effects strong
enough to significantly degrade HF propagation are not likely through
Tuesday.

 Mid-latitude northern hemisphere sunset is 7 minutes earlier and daylength
is 12 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

<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
Virus-free.
www.avg.com
<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>