[RSM] W3LPL: Prop forecast thru Friday/21

[Art Boyars]

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 20 Apr 2023 01:59:15 -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 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, the auroral ovals and polar
regions is likely to be mostly normal through Friday. Mild degradations are
possible at mid and high latitudes during local night time hours through
Friday.

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 30 minutes later and day length
is 77 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 19th Estimated International Sunspot Number was 107. Today's
Solar Flux Index (SFI) is 145 and is likely to decline slightly through at
least Friday. The sun’s visible disk has one very large, three medium and
three tiny active regions containing 43 sunspots with a total sunspot area
of 770 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 of the daylight side
of the Earth caused by M-class solar flares through Friday.

The solar wind is likely to be moderately to strongly elevated at 450
km/second and likely more through at least Friday 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 Friday 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 Friday.

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

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

17 and 15 meter long distance propagation is likely to be mostly 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 mostly normal through
Friday.
12 and 10 meter long distance propagation is likely to be mostly normal
through Friday. 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 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 Friday. 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 Friday 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 Friday 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