[RSM] W3LPL forecast Wed/30 and Thur/1
Art Boyars
artboyars at gmail.com
Wed Jun 30 00:18:18 EDT 2021
From: donovanf at erols.com
To: PVRC Reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 29 Jun 2021 23:49:11 -0400 (EDT)
Subject: [PVRC] Increasing sunspot activity and mostly normal propagation
through Thursday
Long distance propagation forecast for Wednesday and Thursday June 30-July 1
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
Thursday.
Propagation through the auroral ovals and polar regions is likely to be
mostly normal through 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 quiet geomagnetic activity season, only about half
as many geomagnetically disturbed days occur in June and July
compared to the more geomagnetically active equinox seasons.
Sporadic-E propagation occurs every day during June and July
at mid-latitudes in the northern hemisphere making long distance
propagation up to 15,000 km sporadically available in the
17, 15, 12, 10 and 6 meter bands from sunrise through midnight
and occasionally somewhat later.
The solar flux index (SFI) is likely to be at least 93 through
Thursday. Three numbered solar regions with 26 mostly small
sunspots are improving HF propagation on 30 and 20 meters during
late afternoon, nighttime and early morning hours and 17 and 15
meters during day and evening hours.
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 Thursday. 40 meter
short path propagation to south Asia is likely to be normal at about
0015Z through Thursday. 40 meter short path propagation from
North America to east Asia after about 0930Z is likely to be
mostly normal through Thursday.
30 meter propagation through the auroral ovals and polar regions
is likely to be mostly normal 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 increased ionizing solar
radiation in the northern high latitude regions caused by
increased sunspot activity, higher solar elevation angles and
much shorter nights with no source of ionizing solar radiation.
20 meter daytime and evening propagation through the auroral ovals
and polar regions is likely to be mostly normal through Thursday.
20 meter northern transpolar propagation within a few hours of
sunrise and sunset is improving with increased solar ionizing
radiation on the northern polar region caused by increased sunspot
activity and higher solar elevation angles 24 hours per day during
the midnight sun season. 20 meter long distance propagation is
significantly degraded from mid-morning through late afternoon
at low and mid-latitudes in the northern hemisphere by F1 region
midday blanketing of low angle propagation during the summer.
20 meter nighttime long distance propagation in the northern
hemisphere is likely to improve due to increased ionizing solar
radiation in the northern high latitude regions caused by increasing
sunspot activity, higher solar elevation angles and much shorter
nights with no source of ionizing solar radiation.
17 and 15 meter daytime and early evening long distance
propagation in the northern hemisphere is likely to improve due to
increased ionizing solar radiation in the northern high latitude
regions caused by increasing sunspot activity, higher solar elevation
angles and longer days. 17, 15, 12, 10 and 6 meter sporadic-E
propagation up to 15,000 km is likely to be sporadically available
from sunrise through midnight and occasionally later through
late July.
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 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.
IMF field strength, solar wind speed near Earth and geomagnetic
activity are likely to be at background levels through late Wednesday
when weak coronal hole high speed stream influences are likely to
begin to degrade propagation through the auroral ovals through
late Thursday. CMEs, solar flare activity and geomagnetic storms
are not likely through Thursday.
Mid-latitude northern hemisphere sunset is now 77 minutes later
and daylength is 163 minutes longer than it was on the March 20th.
Daylength and solar elevation angle in the northern polar region
will remain nearly constant until late June due to summer solstice
effects.
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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