[RSM] W3LPL prop forecast Fri-Sun, May 7-9

[Art Boyars]

From: donovanf at erols.com
To: PVRC List <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Fri, 7 May 2021 07:19:37 -0400 (EDT)
Subject: [PVRC] Old solar active region 2817 has rotated back onto the
visible disk

Long distance propagation forecast for Friday through Sunday May 7-9


My propagation forecast derived from today's NOAA/SWPC web

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



Propagation is likely to be 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.



The solar flux index (SFI) is likely to be about 72 through Sunday.

SILSO is reporting that a single solar active region (old region 2817)

has rotated onto the visible disk with six sunspots.


www.solarham.net/pictures/2021/may7_2021_disk.jpg


160 and 80 meter short path 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 Sunday. 40 meter short path propagation from North

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

Sunday.



30 meter propagation through the auroral ovals and polar regions is

likely to be normal through 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 propagation in the northern hemisphere is likely to improve

slightly mostly due to longer daylight duration.



20 meter daytime and evening propagation through the auroral

ovals and polar regions is likely to be normal through Sunday.

20 meter northern transpolar propagation within a few hours of

sunrise and sunset will steadily improve with gradually increasing

electron density in the polar F2 region through June. 20 meter night

time long distance propagation in the northern hemisphere is likely

to improve slightly mostly due to longer daylight duration.



17 and 15 meter daytime long distance propagation in the northern

hemisphere is likely to improve slightly mostly due to longer daylight

duration. 12 and 10 meter daytime long distance propagation is likely

to be mostly unreliable and mostly limited to propagation from North

America to Southern Africa, South Atlantic, South America and South

Pacific regions.



Geomagnetic disturbances *caused by coronal hole high speed streams*

are likely to remain mostly brief, minor and less frequent through at

least late 2021. The north-south (Bz) component of the IMF plays a

*crucial role* in triggering all geomagnetic storms. Brief minor to

moderate geomagnetic storms may be gradually triggered when Bz

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* when Bz 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 background levels through Sunday.

Geomagnetic storms and earth directed coronal high speed streams,

solar flares and CMEs strong enough to affect HF propagation are

not likely through Sunday.



Mid latitude northern hemisphere sunset is now 47 minutes later

and daylength is 116 minutes longer than it was on the March 20th.

Daylength is increasing by two minutes per day which is steadily

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, steadily 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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