[RSM] W3LPL forecast Tues/29 - Wed/30

Tue Jun 29 03:48:38 EDT 2021

From: donovanf at erols.com
To: PVRC Reflector <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Mon, 28 Jun 2021 23:44:39 -0400 (EDT)
Subject: [PVRC] Increasing sunspot activity and mostly normal propagation
through Wednesday

Long distance propagation forecast for Tuesday and Wednesday June 29-30

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 through 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 90 through

Wednesday. Three numbered solar regions with 20 small sunspots

are improving HF propagation on 30 and 20 meters at night and

17 and 15 meters during the day.

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 is likely to be normal

at about 0015Z 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 improve due to increased ionizing

solar radiation in the northern high latitude regions caused by

increased sunspot activity, higher solar elevation angles and much

shorter 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 increased solar ionizing radiation

on the northern polar region caused by increased sunspot activity and

higher 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 nighttime 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 increasing sunspot activity, higher solar elevation angles

and much shorter 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 increasing

sunspot activity, higher solar elevation angles and longer 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.

IMF field strength, solar wind speed near Earth and geomagnetic

activity are likely to be at background levels through late Wednesday

when weak coronal hole high speed stream effects may slightly

degrade propagation through the auroral ovals.  CMEs, solar flare

activity and geomagnetic storms are not likely through Wednesday.

Mid-latitude northern hemisphere sunset is now 77 minutes later

and daylength is 163 minutes longer than it was on the March 20th.

Daylength and solar elevation angle in the northern polar region

will remain nearly constant until late June due to 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