[RSM] W3LPL forecast thjru Wed/31

Tue May 30 09:29:04 EDT 2023

From: Frank Donovan <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 30 May 2023 01:31:26 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be normal at low and mid latitudes
and mostly normal at high latitudes. There is a chance of mildly degraded
intervals at high latitudes during local nighttime hours through midday
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 and mid-latitudes is likely to be normal through
Wednesday.

Propagation crossing the auroral ovals and polar regions is likely to be
mostly normal with a chance mildly degraded intervals during local
nighttime hours through midday Wednesday.

VE3EN’s End-of-Day Solar Report is published daily at 0045Z at
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 67 minutes later and day length
is 152 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 sun never sets today in the F2
region over Canada above 48 degrees north latitude.

The May 29th Estimated International Sunspot Number was 157. Today's Solar
Flux Index (SFI) is 154 and likely to decline to about 140 on Wednesday.
The sun’s visible disk has one very large, one large, five medium and two
tiny active regions containing 53 sunspots with a total sunspot area of
1320 micro-hemispheres. (about seven times the surface area of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

Isolated minor to moderate daytime radio blackouts caused by M-class solar
flares are likely through Wednesday. There is a slight chance of strong
daytime radio blackouts caused by X-class solar flares through Wednesday.

The solar wind is lightly enhanced at about 380 km/second due to coronal
hole high speed stream effects, gradually decreasing to near nominal levels
of about 350 km/second or less by early Wednesday.

Geomagnetic activity is likely to quiet unsettled to active through
Wednesday. There is a slight chance of isolated active geomagnetic
conditions from late Tuesday through early Wednesday due to waning coronal
hole high 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 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 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 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 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
mid-September. 12 and 10 meter long path propagation from North America to
east Asia from about 1200Z to 1400Z is likely to be normal through
Wednesday.

6 meter long distance sporadic-E propagation up to 10,000 km and sometimes
more occurs daily in the northern hemisphere from early morning through
evening hours until at least mid-July, but its duration and geographic
location is highly sporadic and unpredictable. 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 chance through Wednesday of 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 slight chance through Wednesday of propagation via
the northern equatorial ionization anomaly from the southern tier of US
states to equatorial Africa during mid-afternoon.  There is a slight chance
through Wednesday of oblique-TEP to the south Pacific and VK/ZL during late
afternoon and early evening through Wednesday. There is a slight chance
that stations in the lower 48 U.S. states may briefly couple into TEP and
oblique-TEP via brief geographically focused intervals of mid-latitude
sporadic-E or enhanced F2 propagation. TEP may be enhanced during the onset
of strong to severe 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
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