[RSM] W3LPL: Mostly normal thru Thurs/22

[Art Boyars]

From: donovanf at erols.com
To: Reflector PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 20 Jul 2021 23:58:15 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation is likely through Thursday July
22nd
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 crossing 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 86 through Thursday.

There are four small active regions on the solar visible disk with

two small and 17 tiny sunspots.

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 at

about 0015Z is likely to be mostly normal 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 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

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

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 mid-day 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

increased sunspot activity, 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 increased

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 to slightly

enhanced through Thursday. The geomagnetic field is likely to be

mostly quiet with a chance of unsettled periods early Thursday.

Mild coronal hole high speed stream effects are possible early

Thursday. CME effects, geomagnetic storms and solar flares strong

enough to affect HF propagation are not likely through Thursday.



Mid-latitude northern hemisphere sunset is now 7 minutes earlier

and daylength is 24 minutes shorter than it was on the June 21st.

Daylength and solar elevation angle in the northern polar region

are slowly declining due to 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