[RSM] W3LPL forecast thru Thursday

Wed Jul 7 13:03:08 EDT 2021

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 7 Jul 2021 02:03:47 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation is likely through Thursday July
8th

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 80 through

Thursday. Solar active region 2835 decreased in magnetic

complexity and area to 300 micro-hemispheres (900 million

square kilometers, 1.5 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 late 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 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 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 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 Thursday.

The solar wind may be slightly enhanced on Wednesday by minor

CME effects. There is a slight chance of brief propagation degradation

at high latitudes on Wednesday from an M-class solar flare. Coronal

hole high speed stream effects and geomagnetic storms not likely

through Thursday.

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

daylength is 8 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 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