[RSM] W3LPL: Normal propagation is likely through Sunday July 18th

[Art Boyars]

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Fri, 16 Jul 2021 00:47:34 -0400 (EDT)
Subject: [PVRC] Normal propagation is likely through Sunday July 18th

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, the auroral ovals

and polar regions is likely to be 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 are two small active regions on the solar visible disk with

one small sunspot and one tiny 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 Sunday.

40 meter short path propagation to south Asia at about 0015Z

is likely to be normal through Sunday. 40 meter short path

propagation from North America to east Asia after about 0930Z

is likely to be normal through Sunday.



30 meter propagation through the auroral ovals and polar regions

is likely to 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 normal through Sunday.

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

levation 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 background state through Sunday.

The geomagnetic field is likely to be mostly quiet through Sunday.

Coronal hole high speed stream and CME effects, geomagnetic storms

and solar flares are not likely through Sunday.



Mid-latitude northern hemisphere sunset is now 5 minutes earlier

and daylength is 19 minutes shorter than it was on the June 21st.

Daylength and solar elevation angle in the northern polar region are

slowly declining 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