[RSM] W3LPL forecast thru Thurs/15

Wed Jul 14 06:04:02 EDT 2021

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 14 Jul 2021 01:03:51 -0400 (EDT)
Subject: [PVRC] Mostly normal near solar minimum propagation is likely
through Thursday July 15th

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 on Wednesday with possible mild degradation

late Wednesday through early Thursday then returning to

mostly normal through late 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 72 or less through

Thursday, approaching solar minimum levels. There is one small

active region on the solar visible disk with one small sunspot.

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 mildly degraded at about 0015Z Thursday. 40 meter short

path propagation from North America to east Asia after about 0930Z

is likely to be mildly degraded on Wednesday and mostly normal

on Thursday.

30 meter propagation through the auroral ovals and polar regions

is likely to mostly normal on Wednesday with possible mild

degradation late Wednesday through early Thursday then returning

to mostly normal through late 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 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 on Wednesday

with possible mild degradation late Wednesday and early Thursday

then returning to mostly normal through late Thursday. 20 meter

northern transpolar propagation within a few hours of sunrise and

sunset is improving with longer duration 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 long

distance 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 at moderately enhanced levels

through Thursday due the coronal hole high speed stream effects.

The geomagnetic field is likely to be quiet to unsettled on

Wednesday, possibly active late Wednesday through early Thursday

then returning to quiet to unsettled through late Thursday.

Geomagnetic storms and CME effects are not likely through

Thursday.

Mid-latitude northern hemisphere sunset is now 3 minutes earlier

and daylength is 15 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

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