[RSM] W3LPL (unformatted): Normal but near min thre Wed/18

[Art Boyars]

Since even the unformatted version got rejected yesterday, I'm Cc'ing Ed
and Cary.  If this does not get thru to the RSM Reflector, maybe one of
them will receive it and figure out how to post it..

From: donovanf at erols.com
To: PVRC Reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Mon, 16 Aug 2021 22:52:45 -0400 (EDT)
Subject: [PVRC] Mostly normal but near solar minimum propagation is likely
to continue through Wednesday August 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 is likely to be

normal but near solar minimum conditions through Wednesday.



Propagation crossing the auroral ovals and polar regions is likely

to be mostly normal but near solar minimum conditions through

Wednesday.



Click here for today’s latest planetary Kp Index, updated every three hours.

Click here for N0NBH’s current HF Band Conditions, updated regularly



We are transitioning into more frequent mildly active geomagnetic

activity through late August. The more geomagnetically active

autumn equinox season begins in September and runs through late

October.



Sporadic-E propagation will be shorter in duration and more

unreliable at mid-latitudes in the northern hemisphere through

late August making long distance propagation up to about 8,000 km

intermittent and unreliable in the 17, 15, 12 and 10 meter bands

from a few hours after sunrise until a few hours after sunset.



The solar flux index (SFI) is likely to be 74 or less through Wednesday.

The sun’s visible disk has one small active region with four tiny

sunspots having no significant effect on propagation.

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 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

F2 propagation. 30 meter night time long distance propagation

in the northern hemisphere is likely to less reliable due to

decreased ionizing solar radiation in the northern high latitude

regions caused by lower solar elevation angles and lengthening

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 less reliable and shorter in

duration due to decreased ionizing solar radiation in the northern

high latitude regions caused by lower solar elevation angles and

lengthening nights with no source of ionizing solar radiation.

20 meter long distance propagation is significantly degraded from

mid-morning through late afternoon at mid and especially low

latitudes in the northern hemisphere by F1 region mid-day

blanketing of low angle long distance propagation through late

August. 20 meter late afternoon, nighttime and early morning

long distance propagation in the northern hemisphere is likely to be

significantly shorter in duration due to decreased ionizing solar

radiation in the northern high latitude regions caused by declining

elevation angles and lengthening nights with no source of ionizing

solar radiation.



17 and 15 meter daytime long distance propagation in the northern

hemisphere is likely to be shorter in duration due to decreased

ionizing solar radiation in the northern high latitude regions caused

by lower solar elevation angles and lengthening nights with no

source of ionizing solar radiation. 17, 15, 12 and 10 meter sporadic-E

propagation up to 8,000 km is likely to be intermittent, short duration

and unreliable from a few hours after sunrise until a few hours after

sunset through late August.



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 likely to be slightly elevated through Wednesday

due to weak coronal hole high speed stream effects. The geomagnetic

field is likely to be mostly quiet with isolated unsettled intervals

through Wednesday due to weak coronal hole high speed stream

effects. CME effects and solar flares strong enough to affect

HF propagation are not likely through Wednesday.



Mid-latitude northern hemisphere sunset is now 37 minutes earlier

and daylength is 77 minutes shorter than it was on the June 21st.

Daylength and solar elevation angle in the northern polar region

have significantly declined due to greatly diminished summer solstice

effects.



Click here for today’s Penticton 10.7 cm solar flux index updated at 1700Z,
2000Z and 2300Z daily.

Click here for today’s three-day GFZ Planetary K Index forecast updated
every three hours.

Click here for today's SIDC Daily Bulletin on Solar and Geomagnetic
Activity updated at 1230Z daily.

Click here for today's SWPC Solar Activity Forecast Discussion updated at
0030Z and 1230Z daily.

Click here 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