[RSM] W3LPL forecast thru Sunday/11

Fri Jul 9 09:40:30 EDT 2021

Here ya' go -- plan your IARU HF 'Test strategy.
73, Art K3KU

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Fri, 9 Jul 2021 01:44:13 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation is likely through Sunday July 11th

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 Sunday.

Propagation through the auroral ovals and polar regions is likely

to be mostly normal through Sunday.

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 75 or less through Sunday.

There is only one active region on the solar visible disk with

only one tiny sunspot. A new active region is likely to rotate onto

the solar visible disk this weekend.

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

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

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

propagation from North America to east Asia after about 0930Z

is likely to be mostly normal through Sunday.

30 meter propagation through the auroral ovals and polar regions

is likely to be mostly normal through Sunday. 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 short 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 Sunday.

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 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 higher solar elevation angles and

short 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 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 on Friday. The solar wind

is expected to beslightly enhanced with a slight increase in geomagnetic

activity on Saturday and Sunday due to weak coronal hole high speed

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

at high latitudes after midday Sunday caused by slightly stronger coronal

high speed stream effects. Coronal mass ejection (CME) effects and

geomagnetic storms not likely through Sunday.

Mid-latitude northern hemisphere sunset is now 1 minute earlier

and daylength is 10 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