[RSM] W3LPL forecast thru Thursday, July 20

Wed Jul 19 05:22:06 EDT 2023

From: Frank W3LPL <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 19 Jul 2023 01:10:29 -0400 (EDT)
Subject: [PVRC] Propagation is likely to be normal at mid and low latitudes
through midday Thursday. Below normal propagation is likely at high
latitudes through Thursday and all latitudes after midday Thursday

My propagation forecast derived from today's NOAA/SWPC web pages and twelve
other online sources (the URLs included in 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
midday Thursday then degrading to below normal due to the effects of
multiple CMEs.   Propagation crossing the auroral ovals and polar regions
is likely to be below normal through Thursday due to polar cap absorption
and the effects of multiple CMEs.
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

SWPC’s estimated planetary Kp Index is updated every three hours at
https://services.swpc.noaa.gov/images/station-k-index.png

N0NBH’s current HF Band Conditions report is updated regularly at
https://www.hamqsl.com/solar.html   Near-real time maps and data about
ionospheric conditions are available at prop.kc2g.com
<http://www.prop.kc2g.com/>

Mid-latitude northern hemisphere sunrise is 15 minutes later and sunset is
eight minutes earlier than it was on June 21st. 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 on the F2
region north of 45 degrees north latitude.

Tuesday’s Estimated International Sunspot Number was 167 and is likely to
increase through Thursday. The sun’s visible disk has three very large. Two
large and three tiny active regions containing 62 sunspots with a total
sunspot area of 1850 micro-hemispheres (about nine times the surface area
of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

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

The solar wind is likely to remain mildly enhanced at about 400 to 450
km/second through midday Thursday, increasing to moderately elevated levels
of about 550 to 600 km/second or more through late Thursday due to effects
of multiple CMEs.

Geomagnetic activity is likely to be mostly quiet to unsettled through
midday Thursday. Minor geomagnetic storms are likely with a chance of
moderate geomagnetic storms and a slight chance of strong geomagnetic
storms after midday Thursday due to the effects of multiple CMEs.
160 and 80 meter propagation from North America to VK/ZL and the
South Pacific is likely to be normal through midday Thursday degrading to
below normal after midday Thursday.

40 meter short path propagation from North America to south Asia after
0000Z is likely to be mostly normal through Thursday. Short path
propagation between North America and east Asia after about 0930Z is likely
to be mostly normal through Thursday.
30 meter propagation through the auroral ovals is likely to be mostly
normal through midday Thursday, degrading to below normal after midday
Thursday. 30 meter propagation transpolar propagation is likely to be below
normal through Thursday. 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 is
likely to be mostly normal through midday Thursday, degrading to below
normal after midday Thursday. 20 meter transpolar propagation is likely to
be below normal through Thursday. 20 meter long distance propagation at low
and mid latitudes in the northern hemisphere is usually degraded from a few
hours before noon until a few hours after noon through late August by E
region and sporadic-E blanketing of long distance low angle F2 propagation.

17 and 15 meter daytime and evening propagation through the auroral ovals
is likely to be mostly normal through midday Thursday, degrading to below
normal after midday Thursday. 17 and 15 meter transpolar propagation is
likely to be below 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 midday Thursday, degrading to below normal after midday Thursday.
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 late September. 12
and 10 meter long path propagation from North America to western Australia
from about 1200Z to 1400Z is likely to be is likely to be mostly normal
through Thursday.

6 meter long distance sporadic-E propagation up to 10,000 km in the
northern hemisphere from early morning through late evening hours is much
more sporadic and unreliable since mid-July. 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 very slight chance through Thursday of brief 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 very slight chance through Thursday of
brief isolated propagation via the northern equatorial ionization anomaly
from the southern tier of US states to equatorial Africa during
mid-afternoon.  There is a very slight chance through Thursday of brief
isolated oblique-TEP to the south Pacific and VK/ZL during late afternoon
and early evening through Thursday. There is a very slight chance that
stations in the lower 48 U.S. states may briefly couple into TEP and
oblique-TEP via geographically focused intervals of mid-latitude sporadic-E
propagation. TEP may be enhanced during the onset of strong to severe solar
flares and 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
exceeding 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

The Penticton 10.7 cm solar flux index is updated daily at 1700, 2000 and
2300Z at:
https://www.spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-flux-en.php

Today's three-day GFZ Planetary K Index forecast is updated every three
hours at:
https://spaceweather.gfz-potsdam.de/fileadmin/ruggero/Kp_forecast/forecast_figures/KP_FORECAST_CURRENT.png

Today's SIDC Daily Bulletin on Solar and Geomagnetic Activity is updated
daily at 1230Z at:
https://www.sidc.be/spaceweatherservices/data/ClassicalRWCproducts/meu

Today's SWPC Solar Activity Forecast Discussion is updated daily at 0030Z
and 1230Z at: https://www.swpc.noaa.gov/products/forecast-discussion

Today's Australian Space Forecast Centre Summary and Forecast is updated
daily at 2330Z at: https://www.sws.bom.gov.au/Space_Weather/1/1

Perhaps the most useful HF propagation pages for DXers can be found at:
http://dx.qsl.net/propagation and https://www.solarham.net