[RSM] W3LPL: Forecast thru Thursday, April 20

[Art Boyars]

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 19 Apr 2023 02:29:39 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be normal at low latitudes and
mostly normal at mid and high latitudes with possible mild degradations
during local night time hours through Thursday

My propagation forecast derived from today's NOAA/SWPC web pages and 12
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, the auroral ovals and polar
regions is likely to be mostly normal through at least Thursday. Mild
degradations are possible at mid and high latitudes during local night time
hours through Thursday.

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 29 minutes later and day length
is 74 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.

The April 19th Estimated International Sunspot Number is 100. Today's Solar
Flux Index (SFI) is 150 and is likely to remain about the same through at
least Thursday. The sun’s visible disk has one very large, four medium and
three tiny active regions containing 72 sunspots with a total sunspot area
of 760 micro-hemispheres (about four times the surface area of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

There is a chance of minor to moderate radio blackouts caused by M-class
solar flares and a slight chance of strong radio blackouts caused by
X-class solar flares through Thursday.

The solar wind is likely to remain moderately to strongly elevated at 450
km/second or more through at least Thursday as a result of the effects of
glancing blows by weak CMEs.

Geomagnetic activity is likely to be quiet to unsettled with a chance of
minor storms intervals through Thursday as a result of the effects of
glancing blows by weak CMEs.

160 and 80 meter propagation from North America to VK/ZL and the
south Pacific is likely to be normal through Thursday.

40 meter short path propagation from North America to south Asia at about
0000Z is likely to be mostly normal through Thursday. Short path
propagation from North America to east Asia after about 0930Z is likely to
be mostly normal through Thursday.

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

17 and 15 meter long distance propagation is likely to be mostly normal
through Thursday. 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 Thursday.
12 and 10 meter long distance propagation is likely to be mostly normal
through Thursday. 12 and 10 meter long distance propagation crossing mid
and high latitudes is beginning to experience mild effects of the normal
seasonal decline in F2 region electron density. 12 and 10 meter long path
propagation from North America to east Asia from about 1200Z to 1400Z is
likely to mostly normal through Thursday. 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 Thursday 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 Thursday 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 fast CME (faster
than 700 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

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