[RSM] W3LPL: Mostly normal thru Wed/21

[Art Boyars]

From: donovanf at erols.com
To: Reflector PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 20 Jul 2021 00:30:07 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation is likely through Wednesday July
21th

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 crossing 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.

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

one small and 13 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

Wednesday. 40 meter short path propagation to south Asia at

about 0015Z is likely to be mostly normal through 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 F

 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

Wednesday. 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 Wednesday. The geomagnetic field is likely

to be mostly quiet with an isolated chance of unsettled periods

through Wednesday. Weak coronal hole high speed stream effects

are possible late Wednesday. CME effects, geomagnetic storms

and solar flares strong enough to affect HF propagation are

not likely through Wednesday.



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