[RSM] W3LPL forecast thru Friday, July 21

[Art Boyars]

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 20 Jul 2023 02:42:47 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be mostly normal through midday
Thursday degrading to below normal through midday Friday, gradually
improving to mostly normal by late Friday

My propagation forecast derived from today's NOAA/SWPC web pages and twelve
other online sources (the URLs are 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 mostly normal
through midday Thursday degrading to below normal through midday Friday,
gradually improving to mostly normal by late Friday.   Propagation crossing
the auroral ovals and polar regions is likely to be mostly normal through
midday Thursday degrading to below normal through midday Friday, gradually
improving to mostly normal by late 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 15 minutes later and sunset is
eight 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.

Today’s Estimated International Sunspot Number is 174 and is likely to be
about the same through Friday. The sun’s visible disk has two very large.
one large, two medium and three tiny active regions containing 63 sunspots
with a total sunspot area of 1660 micro-hemispheres (about eight times the
surface area of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

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

The solar wind is likely to remain mildly enhanced at about 400 to 450
km/second through midday Thursday, increasing to moderately elevated levels
of about 550 to 600 km/second or more through midday Friday due to effects
of multiple CMEs then gradually decreasing to about 500 km/second or less
by late Friday.

Geomagnetic activity is likely to be mostly quiet to unsettled through
midday Thursday. Minor geomagnetic storms are likely with a chance of
moderate geomagnetic storms and a slight chance of strong geomagnetic
storms from midday Thursday to midday Friday due to the effects of multiple
CMEs. Geomagnetic activity is likely to gradually moderate through late
Friday.
160 and 80 meter propagation from North America to VK/ZL and the
South Pacific is likely to be mostly normal through midday Thursday, mostly
below normal through midday Friday then gradually improving to mostly
normal after midday Friday.

40 meter short path propagation from North America to south Asia after
0000Z is likely to be mostly below normal early Friday. Short path
propagation between North America and east Asia after about 0930Z is likely
to be mostly normal on Thursday then mostly below normal on Friday,
30 meter propagation through the auroral ovals and polar regions is likely
to be mostly normal through midday Thursday, mostly below normal through
midday Friday then gradually improving to mostly normal after midday
Friday. 30 meter propagation is always mildly to moderately degraded within
a few 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, mostly
below normal through midday Friday then gradually improving to mostly
normal after midday Friday. 20 meter long distance propagation at low and
mid latitudes in the northern hemisphere is usually degraded from a few
hours before noon until a few 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,
mostly below normal through midday Friday then gradually improving to
mostly normal after 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 propagation is likely to be mostly normal
through midday Thursday, mostly below normal through midday Friday then
gradually improving to mostly normal after midday Friday. 12 and 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
more sporadic and unreliable since mid-July. 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.

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

The Penticton 10.7 cm 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

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