[RSM] W3LPL forecast Wed/30 and Thur/1

Wed Jun 30 00:18:18 EDT 2021

From: donovanf at erols.com
To: PVRC Reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 29 Jun 2021 23:49:11 -0400 (EDT)
Subject: [PVRC] Increasing sunspot activity and mostly normal propagation
through Thursday

Long distance propagation forecast for Wednesday and Thursday June 30-July 1

My propagation forecast derived from today's NOAA/SWPC

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

Propagation crossing low and mid latitudes is likely to be normal through
Thursday.

Propagation through the auroral ovals and polar regions is likely to be
mostly normal through 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 15,000 km sporadically available in the

17, 15, 12, 10 and 6 meter bands from sunrise through midnight

and occasionally somewhat later.

The solar flux index (SFI) is likely to be at least 93 through

Thursday. Three numbered solar regions with 26 mostly small

sunspots are improving HF propagation on 30 and 20 meters during

late afternoon, nighttime and early morning hours and 17 and 15

meters during day and evening hours.

https://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0171.jpg

160 and 80 meter 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 through Thursday. 40 meter short path propagation from

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

mostly normal through Thursday.

30 meter propagation through the auroral ovals and polar regions

is likely to be mostly normal through 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

increased sunspot activity, 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.

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 increased sunspot

activity and higher solar elevation angles 24 hours per day during

the midnight sun season. 20 meter long distance propagation is

significantly degraded from mid-morning through late afternoon

at low and mid-latitudes in the northern hemisphere by F1 region

midday blanketing of low angle 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 increasing

sunspot activity, higher solar elevation angles and much shorter

nights with no source of ionizing solar radiation.

17 and 15 meter daytime and early evening 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 increasing sunspot activity, higher solar elevation

angles and longer days. 17, 15, 12, 10 and 6 meter sporadic-E

propagation up to 15,000 km is likely to be sporadically available

from sunrise through midnight and occasionally later through

late July.

Geomagnetic disturbances *caused by coronal hole high speed*

*stream* effects 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 fast CME.

IMF field strength, solar wind speed near Earth and geomagnetic

activity are likely to be at background levels through late Wednesday

when weak coronal hole high speed stream influences are likely to

begin to degrade propagation through the auroral ovals through

late Thursday.  CMEs, solar flare activity and geomagnetic storms

are not likely through Thursday.

Mid-latitude northern hemisphere sunset is now 77 minutes later

and daylength is 163 minutes longer than it was on the March 20th.

Daylength and solar elevation angle in the northern polar region

will remain nearly constant until late June due to summer solstice

effects.

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