[RSM] W3LPL forecast Tue/1 and Wed/2

Tue Jun 1 04:39:14 EDT 2021

From: donovanf at erols.com
To: PVRC Submissions <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Tue, 1 Jun 2021 01:05:42 -0400 (EDT)
Subject: [PVRC] Sunspot activity is improving propagation but possibly
degraded by CME and coronal high speed stream effects

Long distance propagation forecast for Tuesday and Wednesday June 1-2

My propagation forecast derived from today's NOAA/SWPC

web pages is published five days a week (M-F) in the Daily DX.

Low- propagation is likely to be normal through Wednesday.

Mid-latitude propagation is likely to be mostly normal through

Wednesday.

Propagation through the auroral ovals and polar regions is likely

to be mostly normal through Wednesday with a possibility of

below normal periods from mid-day Tuesday through mid-day

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 14.000 km sporadically available in the

15, 12, 10 and 6 meter bands from sunrise through about midnight.

The solar flux index (SFI) likely to be about 82 through Wednesday.

Two active regions containing eleven tiny sunspots are slightly

improving HF propagation. Solar region 2827 quadrupled in size

during the last 24 hours.

160 and 80 meter short path 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 mostly normal at about 0015Z Wednesday. 40 meter short path

propagation from North America to east Asia after about 0930Z

is likely to be normal on Tuesday and mostly normal on Wednesday.

30 meter propagation through the auroral ovals and polar regions

is likely to be mostly normal through Wednesday with a possibility

of below normal periods from mid-day Tuesday through mid-day

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

increasing sunspot activity and increased ionizing solar radiation

in the northern high latitude regions caused by higher solar elevation

angles and much shorter nights with no ionizing solar radiation.

20 meter daytime and evening propagation through the auroral ovals

and polar regions is likely to be mostly normal through Wednesday

with a possibility of below normal periods from mid-day Tuesday

through mid-day 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

higher solar elevation angles 24 hours per day during the midnight

sun season. 20 meter propagation is significantly degraded from

mid-morning through late afternoon at low and mid-latitudes in the

northern hemisphere by F1 region blanketing of long distance

propagation during the summer. 20 meter nighttime long distance

propagation in the northern hemisphere is likely to improve due to

increasing sunspot activity and increased ionizing solar radiation

in the northern high latitude regions caused by higher solar elevation

angles and much shorter nights with no ionizing solar radiation.

17 and 15 meter daytime long distance propagation in the northern

hemisphere is likely to improve due to increasing sunspot activity,

and increased ionizing solar radiation in the northern high latitude

regions caused by higher solar elevation angles and much longer days.

15, 12, 10 and 6 meter propagation up to 14,000 km is likely to be

sporadically available from sunrise through about midnight through

late July.

Geomagnetic disturbances *caused by coronal hole high speed*

*streams* 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 CME.

IMF field strength, solar wind speed near earth and geomagnetic

activity are likely to be at near ambient levels through mid-day

Tuesday, and possibly enhanced by a glancing blow of an Earth

directed coronal mass ejection (CME) after mid-day Tuesday and

possible effects of an Earth directed coronal hole high speed stream

through mid-day Wednesday.

Mid-latitude northern hemisphere sunset is now 67 minutes later

and daylength is 154 minutes longer than it was on the March 20th.

Daylength is increasing by about one minute per day which is

slowly lengthening the duration of common daylight between distant

locations in the northern hemisphere. The elevation angle of the

midnight sun in the northern polar region is increasing about two

degrees per week, slowly improving 20 meter northern trans-polar
propagation.

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