[RSM] W3LPL forecast thru Friday, Aug. 11

Thu Aug 10 08:42:50 EDT 2023

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 10 Aug 2023 03:03:08 -0400 (EDT)
Subject: [PVRC] Propagation crossing low and mid latitudes is likely to be
normal through Friday. Propagation crossing polar regions is likely to be
mostly below normal through Thursday, improving to normal through Friday

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.

Propagation crossing low and mid latitudes is likely to be normal through
Friday.   Propagation crossing the auroral ovals is likely to be mostly
normal through late Thursday, improving to normal through Friday.
Propagation crossing polar regions is likely to be mostly below normal
through Thursday due to waning S1 solar radiation storm conditions,
improving to normal through Friday.
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
ionospheric conditions are available at https://prop.kc2g.com

Mid-latitude northern hemisphere sunrise is 35 minutes later and sunset is
28 minutes earlier than it was on June 21st. 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. The sun never sets today on the F2
region north of 53 degrees north latitude.

Today’s Estimated International Sunspot Number is 103 and is likely to
remain about the same through Friday. The sun’s visible disk has one large,
three medium and one tiny active region containing 33 sunspots with a total
sunspot area of 540 micro- hemispheres (about three times the surface area
of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

There is a chance of minor daytime radio blackouts caused by M-class solar
flares through Friday.

Solar wind speed is likely to be slightly elevated at about 400 km/second
or less through Thursday, declining to near background levels of about 350
km/second through Friday.

Geomagnetic activity is likely to be quiet to unsettled through late
Thursday due to waning CME and coronal hole high speed stream
effects. There is a chance of active geomagnetic conditions and a
slight chance of minor geomagnetic storm conditions after midday
Thursday caused by a low probability of a glancing blow by a CME.
Geomagnetic activity is likely to be quiet during Friday.
160 and 80 meter propagation from North America to VK/ZL and the
South Pacific is likely to be normal through Friday.
40 meter short path propagation from North America to south Asia after
0000Z is likely to be normal early Friday. Short path propagation between
North America and east Asia after about 0930Z is likely to be normal
through Friday.
30 meter propagation crossing the auroral ovals and is likely to be mostly
normal through Thursday, improving to normal during Friday. 30 meter
propagation crossing polar regions and is likely to be mostly below normal
through late Thursday, improving to normal during Friday. 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 is likely to be mostly
normal through late Thursday, improving to normal through Friday. 20 meter
propagation crossing polar regions and is likely to be mostly below normal
through Thursday, improving to normal through Friday. 20 meter long
distance propagation at low and mid latitudes in the northern hemisphere is
usually degraded from several hours before noon until several hours after
noon through late August by E region and sporadic-E blanketing of long
distance low angle F2 propagation.

17 and 15 meter propagation crossing the auroral ovals and is likely to be
mostly normal through late Thursday, improving to normal through Friday. 17
and 25 meter propagation crossing polar regions and is likely to be mostly
below normal through Thursday, improving to normal through Friday. 17 and
15 meter long path propagation from North America to east Asia from about
1200Z to 1400Z is likely to be normal through Friday.

12 and 10 meter long distance daytime propagation is likely to be normal
through Friday. 12 and especially 10 meter long distance propagation
crossing the north Atlantic and north Pacific is degraded by seasonally
lower daytime MUFs due to reduced daytime free electron density in the F2
region through late September. 12 and 10 meter long path propagation from
North America to western Australia from about 1200Z to 1400Z is likely to
be normal through Friday.

There is a very slight chance of 6 meter long distance sporadic-E
propagation up to about 8000 km in the northern hemisphere from mid-morning
through early evening. Long distance sporadic-E is very unreliable, very
sporadic and much shorter in duration as we approach the end of regular
sporadic-E propagation by mid-August. See K6MIO’s excellent article about 6
meter long distance sporadic-E:
https://www.qsl.net/wa3mej/Articles/Propagation/6M%20Prop/K6MIO/Extreme%20Range%2050-MHz%20Es-%20East–West%20(EWEE).pdf
<https://www.qsl.net/wa3mej/Articles/Propagation/6M%20Prop/K6MIO/Extreme%20Range%2050-MHz%20Es-%20East%E2%80%93West%20(EWEE).pdf>
There is a very slight chance through Friday of very brief isolated 6 meter
F2 trans-equatorial propagation (TEP) from the southern tier of U.S. states
to South America and the south Atlantic (e.g., ZD7) from early afternoon
through late evening. There is a very slight chance through Friday of very
brief isolated propagation via the northern equatorial ionization anomaly
from the southern tier of US states to equatorial Africa during
mid-afternoon.  There is a very slight chance through Friday of very brief
isolated oblique-TEP from the southern tier of US states to the south
Pacific and VK/ZL during late afternoon and early evening through Friday.
There is a very slight chance that more northerly US stations may briefly
couple into TEP and oblique-TEP via geographically focused intervals of
mid-latitude sporadic-E propagation. TEP may be enhanced during the 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 mino 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 remain at about 150 through Friday and 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

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