[RSM] W3LPL forecast thru Friday, July 28

[Art Boyars]

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 27 Jul 2023 02:16:18 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be mostly normal through midday
Thursday. Mild degradation of propagation crossing the auroral ovals is
likely during local late Thursday nighttime hours, improving to mostly
normal before midday 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 and polar regions is
likely to be mostly normal through midday Thursday. Mild degradation is
likely during local late Thursday nighttime hours, improving to mostly
normal before midday 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 prop.kc2g.com
<http://www.prop.kc2g.com/>

Mid-latitude northern hemisphere sunrise is 23 minutes later and sunset is
13 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 45 degrees north latitude.

Wednesday’s Estimated International Sunspot Number was 149 and is likely to
remain about the same through Friday. The sun’s visible disk has two large,
five medium and three tiny active regions containing 47 sunspots with a
total sunspot area of 955 micro-hemispheres (about five times the surface
area of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

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

The solar wind is likely to be mildly enhanced at about 500km/second
through late Wednesday due to CME effects, then gradually improving from
early Friday to about 400 km/second or less by late Friday.

Geomagnetic activity is likely to be unsettled to active through late
Thursday. An isolated minor geomagnetic storm is possible after midday
Thursday due to CME effects. Geomagnetic activity is likely to gradually
improve to mostly quiet after early 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 mostly normal early Friday. Short path propagation
between North America and east Asia after about 0930Z is likely to be
mostly normal through Friday.
30 meter propagation crossing the auroral ovals and polar regions is likely
to be mostly normal through midday Thursday. Mild degradation is likely
during local late Thursday nighttime hours, improving to mostly normal
before midday 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 daytime and evening propagation through the auroral ovals and
polar regions is likely to be mostly normal through midday Thursday. Mild
degradation is likely during local late Thursday nighttime hours, improving
to mostly normal before midday 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 daytime and evening propagation through the auroral ovals
and polar regions is likely to be mostly normal through midday Thursday.
Mild degradation is likely during local late Thursday nighttime hours,
improving to mostly normal before midday Friday. 17 and 15 meter long path
propagation from North America to east Asia from about 1200Z to 1400Z is
likely to be mostly normal through Friday.

12 and 10 meter long distance daytime propagation is likely to be mostly
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 mostly normal through Friday.

6 meter long distance sporadic-E propagation up to 10,000 km in the
northern hemisphere from early morning through late evening hours is much
less reliable, much more sporadic and much shorter in duration as we
approach the end of most sporadic-E propagation in mid-August. See K6MIO’s
excellent article about 6 meter long distance sporadic-E:
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 brief 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 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 brief
isolated oblique-TEP to the south Pacific and VK/ZL during late afternoon
and early evening through Friday. There is a very slight chance that
stations in the lower 48 U.S. states 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 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 remain at about 165 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