[RSM] W3LPL forecast thru Thursday, Aug 31

Wed Aug 30 05:07:43 EDT 2023

From: Frank Donovan <donovanf at starpower.net>
To: PVRC <pvrc at mailman.qth.net>
Cc:
Bcc:
Date: Wed, 30 Aug 2023 01:27:17 -0400 (EDT)
Subject: [PVRC] Propagation crossing low and mid latitudes is likely to be
normal through Thursday. Propagation crossing the auroral ovals and polar
regions is likely to be normal with a chance of mild degradations during
local night time hours through Thursday August 31st

My propagation forecast derived from today's NOAA/SWPC web pages

and twelve other online sources (the URLs included this forecast)

is published five days a week (M-F) in The Daily DX. All days and

times in this forecast are in UTC (Zulu) time.

Propagation crossing low and mid latitudes is likely to be normal

through Thursday.

Propagation crossing the auroral ovals and polar regions is likely

to be normal with a chance of mild degradations during local

night time hours through Thursday.

NWRA’s Table of Space Weather Indices is updated 40 minutes

after every hour at https://spawx.nwra.com/spawx/env_latest.html

SILSO’s Estimated International Sunspot Number is updated

continuously at https://www.sidc.be/silso/DATA/EISN/EISNcurrent.png

SWPC’s estimated planetary Kp Index is updated every three hours at

https://services.swpc.noaa.gov/images/station-k-index.png

N0NBH’s current HF Band Conditions report is updated regularly at

https://www.hamqsl.com/solar.html

Near-real time maps and data about ionospheric conditions are

available at https://prop.kc2g.com

Mid-latitude northern hemisphere sunrise is 54 minutes later and

sunset is 57 minutes earlier than it was on June 21st. Sunrise is

about two hours earlier and sunset is about two hours later at the

300 km altitude of the F2 region than it is at ground level.

The sun never sets today on the F2 region north of 60 degrees

north latitude.

Today’s Estimated International Sunspot Number is 95 and is likely

to remain about the same through Thursday. The sun’s visible disk

has one large and three medium and one tiny active region containing

32 sunspots with a total sunspot area of 640 micro-hemispheres

(about three times the surface area of the Earth).
https://www.sidc.be/spaceweatherservices/applications/solarmap

There is a slight chance of isolated minor to moderate daytime radio

blackouts caused by M-class solar flares through Thursday.

Solar wind speed is likely to be at background levels at about

350 km/second or less.

Geomagnetic activity is likely to be predominantly quiet with a

slight chance of isolated periods of unsettled to active

geomagnetic conditions.

160 and 80 meter propagation from North America to VK/ZL and the

South Pacific is likely to be normal through Thursday.

40 meter short path propagation from North America to south Asia

after 0000Z is likely to be normal through early Thursday. Short

path propagation between North America and east Asia after about

0930Z is likely to be normal through Thursday.

30 meter propagation crossing the auroral ovals and polar regions

is likely to be normal with a chance of mild degradations during

local night time hours through Thursday. 30 meter propagation is

always mildly to moderately degraded within several hours of local

noon by E-region blanketing of long distance low angle F2 propagation.

20 meter propagation crossing the auroral ovals and polar regions

is likely to be normal with a chance of mild degradations during

local night time hours through Thursday. 20 meter long distance

propagation at low and mid latitudes in the northern hemisphere is

usually degraded from several hours before noon until several hours

after noon through late August by E region and sporadic-E blanketing

of long distance low angle F2 propagation.

17 and 15 meter propagation crossing the auroral ovals and polar

regions is likely to be normal with a chance of mild degradations

during local night time hours through Thursday. 17 and 15 meter

long path propagation from North America to southeast and east Asia

from about 1200Z to at least 1400Z is likely to be normal through

Thursday.

12 and 10 meter long distance daytime propagation is likely to be

normal with a chance of mild degradations during local night time

hours through Thursday. 12 and especially 10 meter long distance

propagation crossing the north Atlantic and north Pacific is

degraded by seasonally lower daytime MUFs due to reduced daytime

free electron density in the F2 region through late September.

12 and 10 meter long path propagation from North America to southeast

and east Asia from about 1200Z to at least 1400Z is likely to be

normal through Thursday.

There is a very slight chance through Thursday of very brief

isolated 6 meter F2 trans-equatorial propagation (TEP) from the

southern tier of U.S. states to South America and the south

Atlantic (e.g., ZD7) from early afternoon through late evening.

There is a very slight chance through Thursday of very brief

isolated propagation via the northern equatorial ionization anomaly

from the southern tier of US states to equatorial Africa during

mid-afternoon.  There is a very slight chance through Thursday of

very brief isolated oblique-TEP from the southern tier of US states

to the south Pacific and VK/ZL during late afternoon and early

evening through Thursday. There is a very slight chance that more

northerly US stations may briefly couple into TEP and oblique-TEP

via geographically focused intervals of mid-latitude sporadic-E

propagation. TEP may be enhanced during the onset of strong to

severe solar flares and geomagnetic storms then significantly

degrading after initial enhancement. See K6MIO’s excellent article

on 6 meter TEP, oblique-TEP, TEP-related and mid-latitude

sporadic-E linking to TEP beginning on page 9 at:

http://www.oh3ac.fi/QEX-2016-11.pdf

Persistent southward orientation (-Bz) of the north-south component

of the interplanetary magnetic field (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 IMF field strength

of about 5 nanoteslas 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 IMF field strength mildly stronger than

5 nanoteslas for several hours or more coincident with the effects

of an Earth directed CME and solar wind exceeding 500 km/second.

The Penticton 10.7 cm solar flux index is likely to remain at about

142 through Thursday and is updated daily at 1700, 2000 and 2300Z at:

https://www.spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-flux-en.php

Real time geomagnetic data including Bz orientation, IMF field strength,

solar wind speed and short term k-index forecast are available at:

https://www.swpc.noaa.gov/products/geospace-geomagnetic-activity-plot

Today's three-day GFZ Planetary K Index forecast is updated every three

hours at:

https://spaceweather.gfz-potsdam.de/fileadmin/ruggero/Kp_forecast/forecast_figures/KP_FORECAST_CURRENT.png

Today's SIDC Daily Bulletin on Solar and Geomagnetic Activity is

updated daily at 1230Z at:

https://www.sidc.be/spaceweatherservices/data/ClassicalRWCproducts/meu

Today's SWPC Solar Activity Forecast Discussion is updated daily at

0030Z and 1230Z at:

https://www.swpc.noaa.gov/products/forecast-discussion

Today's Australian Space Forecast Centre Summary and Forecast is updated

daily at 2330Z at:
https://www.sws.bom.gov.au/Space_Weather/1/1

Perhaps the most useful HF propagation pages for DXers can be found at:
http://dx.qsl.net/propagation and https://www.solarham.net