[RSM] W3LPL: Forecast thru Wed, Apr 26

[Art Boyars]

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 25 Apr 2023 02:03:59 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be normal at low latitudes and
mostly normal at mid and high latitudes through Wednesday. Mild to moderate
degradations are possible at mid and high latitudes during local night time
hours through Wednesday

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 latitudes is likely to be normal through Wednesday.

Propagation crossing mid-latitudes is likely to be mostly normal on Tuesday
improving to normal on Wednesday. There is a chance of mild degradations
during local night time hours through early Wednesday.

Propagation crossing the auroral ovals and polar regions is likely to be
mostly normal through Wednesday. Mild to moderate degradations are possible
during local night time hours through early Wednesday.

VE3EN’s End-of-Day Solar Report is published daily at 0045Z at
https://www.solarham.net

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

Click *here* <https://services.swpc.noaa.gov/images/station-k-index.png>
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.
Mid-latitude northern hemisphere sunset is 35 minutes later and day length
is 88 minutes longer than it was on March 20th. 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 April 25th Estimated International Sunspot Number is 43. Today's Solar
Flux Index (SFI) is 134 and is likely to decline slightly by Wednesday. The
sun’s visible disk has one large and five tiny active regions containing 18
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 slight chance of minor to moderate radio blackouts on the
daylight side of the Earth caused by M-class solar flares through Wednesday.

The solar wind is likely to be moderately to strongly elevated at about 500
km/second through mid-day Wednesday as a result of subsiding CME effects
and coronal hole high speed stream effects.

Geomagnetic activity is likely to be quiet to unsettled with a chance of
brief active intervals through Wednesday as a result of subsiding CME
effects and coronal hole high speed stream effects.

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 at about
0000Z is likely to be mostly normal through Wednesday. Short path
propagation from North America to east Asia after about 0930Z is likely to
be mostly normal through Wednesday.

30 meter propagation through the auroral ovals and polar regions is likely
to be mostly normal through Wednesday. 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 Wednesday. 20
meter transpolar propagation within a few hours of sunrise and sunset is
likely to be mostly normal through Wednesday.

17 and 15 meter long distance propagation is likely to be mostly normal
through Wednesday. 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 Wednesday.
12 and 10 meter long distance propagation is likely to be mostly normal
through Wednesday. 12 and 10 meter long distance propagation crossing mid
and high latitudes is beginning to experience mild effects of the normal
seasonal decline of F2 region MUFs due to depleted free electron density.
12 and 10 meter long path propagation from North America to east Asia from
about 1200Z to 1400Z is likely to be mostly normal through Wednesday. 12
and 10 meter F2 propagation crossing northern hemisphere mid-latitudes is
likely to be enhanced when the solar flux index is above 120 and
geomagnetic activity is quiet to unsettled (K index of 3 or less).

There is a chance through Wednesday of F2 trans-equatorial propagation
(TEP) from the southern tier of U.S. states to South America from early
afternoon through late evening. There is a chance through Wednesday of
oblique-TEP from the southern tier and western U.S. states to VK/ZL and the
South Pacific from late afternoon through early evening. There is a lesser
chance that stations at mid-latitudes in the U.S. may briefly couple into
both TEP and oblique-TEP via brief geographically focused intervals of
mid-latitude sporadic-E propagation. TEP and oblique-TEP may be enhanced
during strong to severe geomagnetic storms. See K6MIO’s excellent article
on 6 meter TEP, oblique-TEP, TEP-related and mid-latitude sporadic-E
linking to TEP beginning on page 66 at:
https://k5tra.net/TechFiles/2014%20Central%20States%20whole%20book.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 (faster than
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

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 https://www.solarham.net