[RSM] W3LPL: "Mostly normal propagation is likely through Tuesday July 13th"

[Art Boyars]

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Mon, 12 Jul 2021 00:21:24 -0400 (EDT)
Subject: [PVRC] Mostly normal propagation is likely through Tuesday July
13th

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 latitudes is likely to be normal through

Tuesday.



Propagation crossing mid latitudes is likely to be normal on Monday

and mostly normal on Tuesday.



Propagation through the auroral ovals and polar regions is likely

to be mostly normal on Monday with below normal intervals

through midday Tuesday then returning to mostly normal through

late Tuesday.



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 74 or less through Tuesday.

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

one small sunspot and two 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 Tuesday.

40 meter short path propagation to south Asia is likely to be mostly

normal at about 0015Z Tuesday. 40 meter short path propagation

from North America to east Asia after about 0930Z is likely to be

mostly normal on Monday with below normal intervals on Tuesday.



30 meter propagation through the auroral ovals and polar regions

is likely to mostly normal on Monday with below normal intervals

on Tuesday. 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 Monday with

below normal intervals on Tuesday. 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 moderately enhanced through Tuesday.

The geomagnetic field is likely to be quiet to unsettled on Monday,

unsettled to active through midday Tuesday, then improving the quiet

to unsettled after midday Tuesday. The solar wind is expected to be

moderately enhanced on Monday and Tuesday due coronal hole

high speed stream effects. There is a slight chance of brief propagation

degradation at high latitudes before Tuesday caused by stronger coronal

high speed stream effects. There is a slight chance of a minor geomagnetic

storm before midday Tuesday. Coronal mass ejection (CME) effects

are not likely through Tuesday.



Mid-latitude northern hemisphere sunset is now 2 minutes earlier and

daylength is 13 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