[RSM] W3LPL prop forecast Wed-Thur May 12-13

Wed May 12 05:16:49 EDT 2021

Resuming this forwarding after my computer crashed last Friday afternoon.
Got the new Windows 10 computer running Monday afternoon (with professional
help).  Already checked that N1MM+ is operating correctly.  That was the
first time I have turned on the radio since the Stew Perry contest March 13.

73, Art VE4VTR/VE4AA/K3KU
=======================

From: donovanf at erols.com
To: PVRC List <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 12 May 2021 02:37:02 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation until late Wednesday, degrading
to mostly below normal through mid-day Thursday

Long distance propagation forecast for Wednesday and Thursday May 12-13

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 Thursday.

Mid-latitude propagation in likely to be normal on Wednesday,

degrading to mostly below normal through the first half of

Thursday and improving to mostly normal later in the day.

Propagation through the auroral oval and polar regions is likely

to be mostly normal until late Wednesday, degrading to below

normal through the first half of Thursday and improving to

mostly normal later in the day

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 77 through Thursday.

There are two active regions on the visible disk with 11 small and

tiny sunspots having a minor effect on HF propagation.

160 and 80 meter short path propagation from North America to

VK/ZL and the south Pacific is likely to be normal through Thursday.

40 meter short path propagation to south Asia is likely to be below

normal at about 0015Z Thursday. 40 meter short path propagation

from North America to east Asia after about 0930Z is likely to be

mostly normal on Wednesday and below normal on Thursday.

30 meter propagation through the auroral ovals and polar regions

is likely to be mostly normal until late Wednesday, degrading to

below normal through the first half of Thursday and improving

to mostly normal later in the day. 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 minor sunspot influence and

longer daylight duration.

20 meter daytime and evening propagation through the auroral ovals

and polar regions is likely to be mostly normal until late Wednesday,

degrading to below normal through the first half of Thursday and

improving to mostly normal later in the day. 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 minor sunspot influence and

longer daylight duration.

17 and 15 meter daytime long distance propagation in the northern

hemisphere is likely to improve slightly mostly due to minor sunspot

influence and 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 mostly at background levels through late

Wednesday, degrading to moderately enhanced levels through

the first half of Thursday due the effects of a CME and improving

to slightly enhanced levels later in the day. There is a chance of minor

G1) geomagnetic storms from late Wednesday through mid day

Thursday, with a minor chance of a moderate (G2) geomagnetic

storm during this period. Earth directed solar flares strong enough

to affect HF propagation are not likely through Thursday.

Mid latitude northern hemisphere sunset is now 51 minutes later

and daylength is 124 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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