[RSM] W3LPL: Likely normal thru Thurs/2

Wed Sep 1 14:35:16 EDT 2021

From: *donovanf at erols.com <donovanf at erols.com>*
To: PVRC Reflector <*pvrc at mailman.qth.net <pvrc at mailman.qth.net>*>
Cc:
Bcc:
Date: Wed, 1 Sep 2021 02:15:53 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be mostly normal on Wednesday with
below normal periods on Thursday

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 Thursday.

Propagation crossing mid latitudes is likely to be normal on Wednesday and
mostly normal on Thursday.

Propagation crossing the auroral ovals and polar regions is likely to be
normal on Wednesday and mostly below normal on Thursday.

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 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.

*https://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0171.jpg
<https://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0171.jpg>*

The solar flux index (SFI) is likely to be about 84 through Thursday. The
sun’s visible disk has a tiny active region with one tiny sunspot and a
moderately large active region with 16 small to medium sunspots generally
improving 30 and 20 meter night time propagation and 17 and 15 meter
daytime propagation when the Kp index is 3 or less. A new active region is
rotating onto the northeast limb.

160 and 80 meter propagation from North America to VK/ZL and the south
Pacific is likely to be normal through Thursday. 40 meter short path
propagation to south Asia at about 0000Z is likely to be mostly normal with
below normal periods through Thursday. 40 meter short path propagation from
North America to east Asia after about 0915Z is likely to be mostly normal
with below normal periods on Thursday.

30 meter propagation through the auroral ovals and polar regions is likely
to be mostly normal with below normal periods through 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 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 with below normal periods
through Thursday. 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 when the Kp index
is 3 or less. 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
when the Kp index is 3 or less.

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 when the Kp index is 3 or less.

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 slightly enhanced through mid-day
Wednesday, then moderately enhanced through late Thursday due to influences
of CME activity and weak coronal hole high speed stream effects. The
geomagnetic field is likely to be quiet to unsettled with possible active
intervals through mid-day Wednesday, then unsettled to active through late
Thursday due to influences of CME activity and weak coronal hole high speed
stream effects. A  minor geomagnetic storm is possible through late
Thursday, there is a chance of a moderate

geomagnetic storm on Thursday. Solar flare effects strong enough to
significantly degrade HF propagation are not likely through Thursday.

Mid-latitude northern hemisphere sunset is now 58 minutes earlier and
daylength is 114 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 <http://dx.qsl.net/propagation>* and
*http://www.solarham.net
<http://www.solarham.net>*

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