[RSM] W3LPL prop forecast Wed/2 - Thur/3

Wed Jun 2 05:16:46 EDT 2021

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 2 Jun 2021 02:22:04 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation with possible brief below normal
intervals at high latitudes

Long distance propagation forecast for Wednesday and Thursday June 2-3

My propagation forecast derived from today's NOAA/SWPC

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

Low-band propagation is likely to be normal through Thursday.

Mid-latitude propagation is likely to be mostly normal through

Thursday.

Propagation through the auroral ovals and polar regions is likely

to be mostly normal through Thursday with a possibility of brief

below normal intervals from 0900-1500Z Wednesday and

0300-0600Z Thursday.

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 about midnight.

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

One decaying active region containing ten tiny sunspots is 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

Thursday. 40 meter short path propagation to south Asia is likely

to be 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 then improving to

normal on Thursday.

30 meter propagation through the auroral ovals and polar regions

is likely to be mostly normal through Thursday with a possibility

of brief below normal intervals from 0900-1500Z Wednesday and

0300-0600Z Thursday. 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 Thursday

with a possibility of brief below normal intervals from 0900-1500Z

Wednesday and 0300-0600Z Thursday. 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 about midnight 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 Thursday with

possible weak to moderate enhancements caused by a glancing blow

of an Earth directed coronal mass ejection (CME) from 0900-1500Z

Wednesday and a possible effects of a Earth directed coronal hole

high speed stream from 0300-0600Z Thursday.

Mid-latitude northern hemisphere sunset is now 68 minutes later and

daylength is 155 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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