[RSM] W3LPL forecast through Wed/7

Tue Jul 6 04:22:58 EDT 2021

From: donovanf at erols.com
To: Radio Club <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 6 Jul 2021 01:11:34 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation is likely through Wednesday July
7th

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 Wednesday.

Propagation through the auroral ovals and polar regions is likely

to be mostly normal through Wednesday.

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 85 through

Wednesday. Solar active region 2835 decreased in magnetic

complexity and area to 470 micro-hemispheres (1.4 billion

square kilometers, 2.5 times the surface area of the Earth).

Region 2835 continues to significantly improve HF propagation

on 30 and 20 meters during late afternoon, nighttime and early

morning hours and 17 and 15 meter propagation from sunrise

through early evening but will rotate off the west limb of the

solar visible disk on Wednesday.

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 seasonably normal through

Wednesday. 40 meter short path propagation to south Asia is likel

 to be normal at about 0015Z Wednesday. 40 meter short path

propagation from North America to east Asia after about 0930Z

is likely to be mostly normal through Wednesday.

30 meter propagation through the auroral ovals and polar regions

is likely to be mostly normal through Wednesday. 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 Wednesday.

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 high 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 late afternoon, nighttime and early morning 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 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, high solar elevation angles and long 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.

The solar wind is expected to be near background levels and the

geomagnetic field is likely to be mostly quiet through Wednesday.

The solar wind may be slightly enhanced on Wednesday by minor

CME effects. Geomagnetic storms and solar flares are not likely

through Wednesday.

Mid-latitude northern hemisphere sunset is now 1 minute earlier and

daylength is 4 minutes shorter than it was on the June 21st. Daylength

and solar elevation angle in the northern polar region are slowly

declining through mid-July due to gradually waning summer solstic

 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