[RSM] W3LPL weekend forecast Fri/4 - Sun/6

Fri Jun 4 09:33:57 EDT 2021

To: PVRC Submissions <pvrc at mailman.qth.net>
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Date: Fri, 4 Jun 2021 01:48:51 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation through Sunday

Long distance propagation forecast for Friday through Sunday June 4-6

My propagation forecast derived from today's NOAA/SWPC

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

Low latitude propagation is likely to be normal through Sunday.

Mid-latitude propagation is likely to be mostly normal through

Saturday gradually improving to normal on Sunday.

Propagation through the auroral ovals and polar regions is likely

to be mostly normal through Sunday.

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 14,000 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 75 through Sunday.

Two active regions containing ten 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 Sunday. 40 meter

short path propagation to south Asia is likely to be normal at about

0015Z through Sunday. 40 meter short path propagation from North

America to east Asia after about 0930Z is likely to be mostly normal

through Saturday and normal on Sunday.

30 meter propagation through the auroral ovals and polar regions is

likely to be mostly normal through Saturday gradually improving to

normal on Sunday. 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 Saturday

gradually improving to normal on Sunday. 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 14,000 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 may have slight enhancements during Friday due to the

possible influence of weak coronal hole high speed stream effects,

gradually improving to ambient levels on Sunday. CME and

solar flare activity is not expected through Sunday.

Mid-latitude northern hemisphere sunset is now 71 minutes later

and daylength is 158 minutes longer than it was on the March 20th.

Daylength is increasing by about one minute per day which is slowly

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 two

degrees per week, slowly 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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