[RSM] W3LPL forecast Thur-Fri June 3-4

Thu Jun 3 14:32:49 EDT 2021

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Thu, 3 Jun 2021 00:31:49 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation through Friday

Long distance propagation forecast for Thursday and Friday June 3-4

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 through Friday with a possibility of brief

below normal intervals near midday 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 14,000 km sporadically available in the

15, 12, 10 and 6 meter bands from sunrise through midnight or later.

The solar flux index (SFI) likely to be about 75 through Friday.

Two active regions containing ten tiny sunspots are slightly improving

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 Friday.

40 meter short path propagation to south Asia is likely to be 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 through Friday with a possibility of

brief below normal intervals near midday 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

olar 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 Friday with

a possibility of brief below normal intervals near midday 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 propagation is significantly degraded from mid-morning

through late afternoon at low and mid-latitudes in the northern

hemisphere by F1 region blanketing of long distance 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. 15, 12, 10 and 6 meter

sporadic-E propagation up to 14,000 km is likely to be sporadically

available from sunrise through midnight or 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 with

possible slight to moderate enhancements near midday Friday due

to the possible influence of a coronal high speed stream and lingering

weak CME effects.

Mid-latitude northern hemisphere sunset is now 69 minutes later

and daylength is 156 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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