[RSM] W3LPL forecast Thur/10 - Fro/11

Thu Jun 10 05:02:05 EDT 2021

See W3LPL's presentation at the RSM Zoom meeting this evening.  I hope to
be there.
73, Art K3KU/VE4VTR

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 10 Jun 2021 00:18:04 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation likely through Friday

Long distance propagation forecast for Thursday and Friday June 10-11

My propagation forecast derived from today's NOAA/SWPC

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

Low and mid latitude propagation is likely to be normal through Friday.

Propagation through the auroral ovals and polar regions is likely

to be mostly normal with possible below normal intervals on

Thursday improving to mostly normal on 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 78 through Friday.

Two active regions containing 11 tiny sunspots are slightly

improving 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 mostly 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 with possible below normal intervals

on Thursday improving to mostly normal on 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 with possible below

normal intervals on Thursday improving to mostly normal on 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 much 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*

*streams *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 CME.

IMF field strength, solar wind speed near Earth and geomagnetic

activity are likely to be at near ambient levels through Friday.

CME, solar flare activity and geomagnetic storms are not likely

through Friday.

Mid-latitude northern hemisphere sunset is now 73 minutes later

and daylength is 161 minutes longer than it was on the March 20th.

Daylength is increasing by less than one minute per day which is

slightly lengthening the duration of common daylight between

distant locations in the northern hemisphere. The elevation angle

of the midnight sun in the northern polar region is increasing about

one degree per week, slightly improving 20 meter northern

trans-polar propagation.

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

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