[RSM] W3LPL: The sun is finally exhibiting sunspot activity that increases MUFs

Thu May 27 04:45:36 EDT 2021

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 27 May 2021 02:10:04 -0400 (EDT)
Subject: [PVRC] The sun is finally exhibiting sunspot activity that
increases maximum usable frequencies (MUFs)

Long distance propagation forecast for Thursday and Friday May 27-28

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 Friday.

Mid-latitude propagation is likely to be mostly normal on Thursday

improving to normal through Friday.

Propagation through the auroral ovals and polar regions is likely

to be mostly below normal on Thursday improving to 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.

The sun is finally exhibiting sunspot activity that increases

maximum usable frequencies (MUFs). The solar flux index (SFI)

is likely to be about 88 through Friday. Active region 2824 has

five small to intermediate sunspots that are increasing MUFs.

New active region 2826 has nine mostly small sunspots that

slightly increase MUFs.

160 and 80 meter short path 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

below normal at about 0015Z Friday. 40 meter short path

propagation from North America to east Asia after about 0930Z

is likely to be mostly below normal on Thursday gradually

improving to mostly normal through Friday.

30 meter propagation through the auroral ovals and polar regions

is likely to be mostly below normal on Thursday gradually improving

to 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 propagation in the northern hemisphere is likely to

improve due to increased sunspot activity and longer daylight

duration.

20 meter daytime and evening propagation through the auroral

ovals and polar regions is likely to be mostly below normal on

Thursday gradually improving to mostly normal through Friday.

20 meter northern transpolar propagation within a few hours of

sunrise and sunset is improving with increased sunspot activity.

20 meter night time long distance propagation in the northern

hemisphere is likely to improve due to increased sunspot activity

and longer daylight duration.

17 and 15 meter daytime long distance propagation in the northern

hemisphere is likely to improve due to increased sunspot activity

and longer daylight duration. 15, 12 and 10 meter daytime and

evening long distance propagation is likely to be sporadically

enhanced by sporadic-E propagation through 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 decline to moderately enhanced levels on

Thursday gradually declining to slightly enhanced levels on Friday

as CME effects weaken. Earth directed coronal high speed streams

are not likely through Friday. There is a slight chance that M-Class

solar flares may briefly degrade HF propagation on the sun-facing

side of the earth through Friday.

Mid-latitude northern hemisphere sunset is now 64 minutes later

and daylength is 148 minutes longer than it was on the March 20th.

Daylength is increasing by just over 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

three degrees per week, slowly improving 20 meter northern

trans-polar propagation through June.

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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