[RSM] W3LPL forecast thru Sun/29

[Art Boyars]

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Fri, 27 Aug 2021 01:11:39 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be mostly normal through
Saturday and normal on Sunday August 29th

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 is likely to be normal
through Sunday.

Propagation crossing the auroral ovals and polar regions is likely to
be mostly normal through Saturday improving to normal on Sunday.

Click here for today’s latest planetary Kp Index, updated every three hours.

Click here for N0NBH’s current HF Band Conditions, updated regularly

We have transitioned into more frequent mildly active geomagnetic
activity during late August. The more geomagnetically active autumn
equinox season begins in September and runs through late October with
about twice as many geomagnetically active days as June, July,
December and January.

Sporadic-E propagation will be shorter in duration with much lower
MUFs and much less reliable at mid-latitudes in the northern
hemisphere during late August making long distance sporadic-E
propagation up to about 8,000 km intermittent and unreliable in the 17
and 15 meter bands from a few hours after sunrise until a few hours
after sunset.

The solar flux index (SFI) is likely to be 93 or higher through
Sunday. The sun’s visible disk has three active regions with 17 small
sunspots generally improving 30 and 20 meter night time propagation
and 17 and 15 meter daytime propagation.
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 Sunday. 40 meter short path
propagation to south Asia at about 0015Z is likely to be mostly normal
through Sunday. 40 meter short path propagation from North America to
east Asia after about 0930Z is likely to be mostly normal through
Sunday.

30 meter propagation through the auroral ovals and polar regions is
likely to be mostly normal through Saturday improving to normal on
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 night time long distance propagation
in the northern hemisphere is likely to improve due to increasing
solar ionizing radiation caused by increased sunspot activity.

20 meter daytime and evening propagation through the auroral ovals and
polar regions is likely to be mostly normal through Saturday improving
to normal on Sunday. 20 meter northern transpolar propagation within a
few hours of sunrise and sunset is likely to improve due to increasing
solar ionizing radiation caused by increased sunspot activity. 20
meter long distance propagation is significantly degraded from
mid-morning through late afternoon at mid and especially low latitudes
in the northern hemisphere by F1 region mid-day blanketing of low
angle long distance propagation through late August. 20 meter late
afternoon, nighttime and early morning long distance propagation in
the northern hemisphere is likely to improve due to increasing solar
ionizing radiation caused by increased sunspot activity.

17 and 15 meter daytime long distance propagation in the northern
hemisphere is likely to improve due to increasing solar ionizing
radiation caused by increased sunspot activity. 17 and 15 meter
sporadic-E propagation up to about 8,000 km is likely to be
intermittent, short duration and unreliable from a few hours after
sunrise until a few hours after sunset during late August.

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 through Saturday
due to coronal hole high speed stream effects and a slight chance of a
weak glancing blow by two passing CMEs, then improving to background
wind speeds on Sunday. The geomagnetic field is likely to be quiet to
unsettled with active periods through Saturday due to coronal hole
high speed stream effects and a slight chance of a weak glancing blow
by two passing CMEs, improving to mostly quiet on Sunday. There is a
chance of a minor geomagnetic storm on Friday and Saturday. Solar
flares strong enough to significantly degrade HF propagation are not
likely through Sunday.

Mid-latitude northern hemisphere sunset is now 52 minutes earlier and
daylength is 103 minutes shorter than it was on the June 21st.
Daylength and solar elevation angle in the northern polar region have
significantly declined due to the end of the midnight sun and the
approaching autumn equinox.

Click here for today’s Penticton 10.7 cm solar flux index updated at
1700Z, 2000Z and 2300Z daily.

Click here for today’s three-day GFZ Planetary K Index forecast
updated every three hours.

Click here for today's SIDC Daily Bulletin on Solar and Geomagnetic
Activity updated at 1230Z daily.

Click here for today's SWPC Solar Activity Forecast Discussion updated
at 0030Z and 1230Z daily.

Click here 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