[RSM] W3LPL: Forecast Friday/5 thru Sunday/7

[Art Boyars]

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Fri, 5 May 2023 01:48:56 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be normal at all latitudes on
Friday then degrading slightly to mostly normal at mid and high latitudes
through Sunday. There is a slight chance of brief mild degradations at high
latitudes during local night time hours on Saturday and Sunday

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 Sunday.

Propagation crossing mid latitudes is likely to be normal on Friday then
slightly degrading to mostly normal through Sunday.

Propagation crossing the auroral ovals and polar regions is likely to be
normal on Friday then slightly degrading to mostly normal through
Sunday.  There is a slight chance of brief mild degradations during
Saturday and Sunday local night time hours.

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 46 minutes later and day length
is 112 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. On this date the sun never sets in
the F2 region at distances more than 400 miles north of the lower 48 US
states.

The May 4th Estimated International Sunspot Number was 134. Today's Solar
Flux Index (SFI) is 162 and likely to be about the same through Sunday. The
sun’s visible disk has one very large, two large, one medium and four tiny
active regions containing 59 sunspots with a total sunspot area of 1220
micro-hemispheres (about six times the surface area of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

There is a chance of isolated minor to moderate radio blackouts the
daylight side of the Earth caused by M-class solar flares on Friday and a
diminished chance over the weekend. There is a slight chance of strong
radio blackouts caused by X-class flares through Sunday.

The solar wind is likely to be decline to about 400 km/second or less on
Friday then elevating to about 500 km/second through Sunday due to coronal
hole high speed stream effects. There is a chance of CME influence during
mid-day Sunday.

Geomagnetic activity is likely to be quiet on Friday, then degrading to
quiet to unsettled from early Saturday through mid-day Sunday due to
coronal hole high speed stream effects and a chance of CME influence before
mid-day Sunday. There is a chance of active geomagnetic conditions and a
slight chance of an isolated minor geomagnetic storm from mid-day Saturday
through mid-day Sunday due o coronal hole high speed stream effects. There
is a chance of CME influence during mid-day Sunday.

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

40 meter short path propagation from North America to south Asia at about
0000Z is likely to be normal on Friday then degrading slightly to mostly
normal through mid-day Sunday. Short path propagation from North America to
east Asia after about 0930Z is likely to be normal on Friday then degrading
slightly to mostly normal on Sunday.

30 meter propagation through the auroral ovals and polar regions is likely
to be normal on Friday then degrading slightly to mostly normal through
mid-day Sunday. 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 normal on Friday then degrading slightly
to mostly normal through mid-day Sunday. 20 meter transpolar propagation
within a few hours of sunrise and sunset is likely to be normal on Friday
then slightly degrading to mostly normal through mid-day Sunday.

17 and 15 meter long distance propagation is likely to be normal on Friday
then degrading slightly to mostly normal through mid-day Sunday. 17 and 15
meter long path propagation from North America to east Asia from about
1200Z to 1400Z is likely to be normal on Friday then degrading slightly to
mostly normal on Sunday.

12 and 10 meter long distance propagation is likely to be normal on Friday
then degrading slightly to mostly normal through mid-day Sunday. 12 and 10
meter long distance propagation crossing mid and high latitudes is
beginning to experience the normal seasonal decline of F2 region MUFs due
to reduced 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
likely to be normal on Friday then degrading slightly to mostly normal on
Sunday. 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 Sunday of 6 meter 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 lesser chance through Sunday of
oblique-TEP from the southern tier of US states to equatorial Africa during
mid-afternoon and to VK/ZL and the south Pacific from late afternoon
through early evening. There is a slight chance that stations at
mid-latitudes in the U.S. may briefly couple into TEP and oblique-TEP via
brief geographically focused intervals of mid-latitude sporadic-E
propagation. TEP may be enhanced during the onset of 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 and solar wind
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