[RSM] W3LPL forecast Thur Fri -- attempt #5

Thu Jun 24 10:21:41 EDT 2021

I think I've missed a day or two, and now the mail server has twice blocked
several attempts to send my copy-and-paste.  Maybe this time it will work..

Frank's message says "June 23 - 24", but my calendar says Thursday is 24th.

73, Art VE4VTR/K3KU

From: donovanf at erols.com
To: PVRC Reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 23 Jun 2021 23:18:59 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation through Friday

Long distance propagation forecast for Thursday-Friday June 23-24

My propagation forecast derived from today's NOAA/SWPC

web pages is published five days a week (M-F) in the Daily DX.

Propagation crossing low and mid latitudes is likely to be normal through
Friday.

Propagation through the auroral ovals and polar regions is likely to be
mostly normal through Friday

Click *here* <https://services.swpc.noaa.gov/images/planetary-k-index.gif>
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.

We are in the quiet geomagnetic activity season, only about half

as many geomagnetically disturbed days occur in June and July

compared to the more geomagnetically active equinox seasons.

Sporadic-E propagation occurs every day during June and July

at mid-latitudes in the northern hemisphere making long distance

propagation up to 15,000 km sporadically available in the

17, 15, 12, 10 and 6 meter bands from sunrise through midnight

and occasionally somewhat later.

The solar flux index (SFI) is likely to be about 80 through Friday.

One small sunspot is having a minor effect on HF propagation.

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 to south Asia is likely to be normal at about

0015Z Friday. 40 meter 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 significantly degraded within a few hours of local noon

because of E-region blanketing of long distance F2 propagation.

30 meter night time long distance propagation in the northern

hemisphere is likely to improve due to increased ionizing solar

radiation in the northern high latitude regions caused by higher solar

elevation angles and much shorter nights with no source of ionizing

solar radiation.

20 meter daytime and evening propagation through the auroral ovals

and polar regions is likely to be mostly normal through Friday.

20 meter northern transpolar propagation within a few hours of

sunrise and sunset is improving with increased solar ionizing

radiation on the northern polar region caused by higher solar

elevation angles 24 hours per day during the midnight sun season.

20 meter long distance propagation is significantly degraded from

mid-morning through late afternoon at low and mid-latitudes in the

northern hemisphere by F1 region midday blanketing of low angle

propagation during the summer. 20 meter nighttime long distance

propagation in the northern hemisphere is likely to improve due to

increased ionizing solar radiation in the northern high latitude regions

caused by higher solar elevation angles and much shorter nights

with no source of ionizing solar radiation.

17 and 15 meter daytime long distance propagation in the northern

hemisphere is likely to improve due to increased ionizing solar

radiation in the northern high latitude regions caused by higher

solar elevation angles and longer days. 17, 15, 12, 10 and 6 meter

sporadic-E propagation up to 15,000 km is likely to be sporadically

available from sunrise through midnight and occasionally later

through late July.

Geomagnetic disturbances *caused by coronal hole high speed stream*

effects are likely to remain mostly brief, minor and somewhat less

frequent through at least late 2021. The southward oriented (-Bz)

component of the 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 enhanced IMF

field strength 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 enhanced IMF field strength

for several hours or more *coincident with* the effects of an Earth

directed fast CME.

IMF field strength, solar wind speed near Earth and geomagnetic

activity are likely to be near background levels through Friday

with the possibility of brief slight enhancements by declining

coronal hole high speed stream effects. Geomagnetic storm,

CME and solar flare activity are not likely through Friday.

Mid-latitude northern hemisphere sunset is now 77 minutes later

and daylength is 164 minutes longer than it was on the March 20th.

Daylength and solar elevation angle in the northern polar region

will remain nearly constant until late June due to summer solstice

effects.

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 http://www.solarham.net