[RSM] W3LPL propagation forecast thru Wednesday, Sept. 27

Tue Sep 26 02:17:11 EDT 2023

(Wow! Has it really been over three weeks since I managed to find time to
send these forecasts? Nobody mentioned it.  Please let me know (direct
email) if you want to keep receiving them. -- Art K3KU/VE4VTR)

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 26 Sep 2023 01:24:27 -0400 (EDT)
Subject: [PVRC] Low latitude propagation is likely to be normal through
Wednesday. Mid latitude propagation is likely to be mostly normal Tuesday,
normal Wednesday. High latitude propagation is likely to be mostly below
normal Tuesday, mostly normal Wednesday

My propagation forecast derived from today's NOAA/SWPC web pages and twelve
other online sources (the URLs included this forecast) is published five
days a week (M-F) in The Daily DX. All days and times in this forecast are
in UTC (Zulu) time.
NWRA’s Table of Space Weather Indices is updated 40 minutes after every
hour at https://spawx.nwra.com/spawx/env_latest.html

SILSO’s Estimated International Sunspot Number is updated continuously at
https://www.sidc.be/silso/DATA/EISN/EISNcurrent.png

SWPC’s estimated planetary Kp Index is updated every three hours at
https://services.swpc.noaa.gov/images/station-k-index.png

N0NBH’s current HF Band Conditions report is updated regularly at
https://www.hamqsl.com/solar.html   Near-real time maps and data about HF
ionospheric propagation are available at https://prop.kc2g.com

Mid-latitude northern hemisphere sunrise is two minutes later and sunset is
three minutes earlier than it was on September 23rd. Sunrise is about two
hours earlier and sunset is about two hours later at the 300 km altitude of
the F2 region than it is at ground level.

Today’s Estimated International Sunspot Number is 168 and is likely to
remain about the same through Wednesday. The sun’s visible disk has three
large, three medium and four tiny active regions containing 72 sunspots
with a total sunspot area of 950 micro-hemispheres (about five times the
surface area of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

Minor to moderate daytime radio blackouts caused by M-class solar flares
are likely through Wednesday.

Solar wind speed is likely to be moderately elevated to about 500 km/second
or less through Tuesday due to CME effects then gradually declining to 400
km/second or less on Wednesday due to waning effects of a possible glancing
CME blow late Tuesday.
Mostly unsettled to active geomagnetic conditions are likely with possible
brief mild geomagnetic storm conditions on Tuesday due to CME effects.
Mostly quiet geomagnetic conditions are likely with possible unsettled to
active intervals on Wednesday due to waning effects of a possible glancing
CME blow late Tuesday.
160 and 80 meter propagation from North America to VK/ZL and the
South Pacific is likely to be normal through Wednesday.
40 meter short path propagation from North America to south Asia after
about 2300Z is likely to be mostly normal late Tuesday improving to normal
late Wednesday. Short path propagation between North America and east Asia
after about 0900Z is likely to be mostly below normal on Tuesday improving
to mostly normal on Wednesday.
30 meter propagation crossing the auroral ovals and polar regions is likely
to be mostly below normal on Tuesday improving to mostly normal on
Wednesday. 30 meter propagation is always mildly to moderately degraded
within several hours of local noon by E-region blanketing of long distance
low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions is likely
to be mostly below normal on Tuesday improving to mostly normal on
Wednesday. 20 meter long distance propagation at low latitudes is usually
degraded from several hours before noon until several hours after local
solar noon by E region blanketing of long distance low angle F2 propagation.

17 and 15 meter propagation crossing the auroral ovals and polar regions is
likely to be mostly below normal on Tuesday improving to mostly normal on
Wednesday. 17 and 15 meter long path propagation from North America to
southeast and east Asia from about 1200Z to at least 1400Z is likely to be
mostly below normal on Tuesday improving to normal on Wednesday.

12 and 10 meter long distance daytime propagation is likely to be mostly
below normal on Tuesday improving to mostly normal on Wednesday. 12 and 10
meter long path propagation from North America to southeast and east Asia
from about 1200Z to at least 1400Z is likely to be mostly below normal on
Tuesday improving to normal on Wednesday.   We are in the autumnal equinox
season when disturbed geomagnetic conditions are much more likely than
during the solstice seasons.
There is a chance of 6 meter F2 trans-equatorial propagation (TEP) from the
southern tier of U.S. states to South America during early evening. There
is a very slight chance of very brief isolated propagation via the northern
equatorial ionization anomaly from the southern tier of US states to
equatorial Africa and the south Atlantic (e.g., ZD7 and ZD9) during
mid-afternoon. There is a very slight chance of very brief isolated
oblique-TEP from the southern tier of US states to the south Pacific and
VK/ZL during early evening. There is a chance that more northerly US
stations may couple into TEP and oblique-TEP via geographically focused
intervals of mid-latitude sporadic-E and intervals mid-latitude F region
ionization irregularities. TEP may be significantly enhanced during the
late afternoon through early evening onset of strong to severe solar flares
and geomagnetic storms then significantly degrading after initial
enhancement. See K6MIO’s excellent article on 6 meter TEP, oblique-TEP,
TEP-related and mid-latitude sporadic-E linking to TEP beginning on page 9
at: http://www.oh3ac.fi/QEX-2016-11.pdf

Persistent southward orientation (-Bz) of the north-south 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 IMF field strength of about 5 nanoteslas
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
IMF field strength mildly stronger than 5 nanoteslas for several hours
or more coincident with the effects of an Earth directed CME and solar wind
exceeding 500 km/second.   The Penticton 10.7 cm solar flux index is likely
to be about 170 through Wednesday. The solar flux index is updated daily at
1700, 2000 and 2300Z at:
https://www.spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-flux-en.php

Real time geomagnetic data including Bz orientation, IMF field strength,
solar wind speed and short term k-index forecast are available at:
https://www.swpc.noaa.gov/products/geospace-geomagnetic-activity-plot

Today's three-day GFZ Planetary K Index forecast is updated every three
hours at:
https://spaceweather.gfz-potsdam.de/fileadmin/ruggero/Kp_forecast/forecast_figures/KP_FORECAST_CURRENT.png

Today's SIDC Daily Bulletin on Solar and Geomagnetic Activity is updated
daily at 1230Z at:
https://www.sidc.be/spaceweatherservices/data/ClassicalRWCproducts/meu

Today's SWPC Solar Activity Forecast Discussion is updated daily at 0030Z
and 1230Z at: https://www.swpc.noaa.gov/products/forecast-discussion

Today's Australian Space Forecast Centre Summary and Forecast is updated
daily at 2330Z at: https://www.sws.bom.gov.au/Space_Weather/1/1

Perhaps the most useful HF propagation pages for DXers can be found at:
http://dx.qsl.net/propagation and https://www.solarham.net