ARLP036 The ARRL Solar Report undefined

 

 

 

SB PROP @ ARL $ARLP036

 

ARLP036 Propagation Forecast

 

ZCZC AP36

QST de W1AW

Propagation Forecast Bulletin 36 ARLP036

From ARRL Headquarters

Newington, CT September 4, 2026

To all radio amateurs

 

SB PROP ARL ARLP036

ARLP036 The ARRL Solar Report

 

Forecast of Solar and Geomagnetic Activity, courtesy of NOAA Space Weather Prediction Center, 31 August - 26 September 2026.

 

Solar activity is expected to be at very low to low levels, with a chance for moderate levels and a slight chance for high levels throughout the forecast period.

 

No proton events are expected at geosynchronous orbit.

 

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high levels on 31 Aug - 06 Sep, then again from 16-23 Sep. Levels are expected to be at normal to moderate levels from 07 - 15 Sep, and again from 24-26 Sep.

 

Geomagnetic field activity is expected to decrease from unsettled levels on 31 Aug to mostly quiet levels from 01-11 Sep and again from 17-23 Sep. Unsettled to active conditions are expected from 12-16 Sep due to negtive polarity CH HSS influence, then again from 24-26 Sep under positive polarity CH HSS influence.

 

Weekly Commentary on the Sun, the agnetosphere, and the Earth's Ionosphere, September 3, 2026

 

A moderately strong solar flare (class M3.0), which peaked in the northeastern part of the solar disk on September 2 at 19:36 UTC, was accompanied by a coronal mass ejection (CME). This occurred in NOAA active region No. 4524, which was observed as NOAA No. 4510 during the previous solar rotation. Based on its reappearance and activity, we can conclude that the expected decline in overall solar activity in the first half of September will not be as severe as originally anticipated.

 

In the first half of September, we can expect only a very gradual increase in solar activity and likely only a few geomagnetically active days. Above all, however, we can expect a recurring rise in solar activity around the autumn equinox which is precisely the combination that typically leads to a noticeable improvement in ionospheric propagation of shortwave signals. The subsequent rise

in geomagnetic activity immediately following the equinox could, with a bit of luck, bring another brief, follow-up improvement at its onset.

 

The Predicted Planetary A Index for September 4 to September 10 is 5, 5, 5, 5, 5, 5, and 5 with a mean of 5.0. The Predicted Planetary K Index is 2, 2, 2, 2, 2, 2, and 2 with a mean of 2.0. 10.7 centimeter flux is 100, 95, 95, 95, 95, 100, and 100 with a mean of 97.1.

 

For more information concerning shortwave radio propagation, see and the ARRL Technical Information Service web page at . For an explanation of numbers used in this bulletin, see . Information and tutorials on propagation can be found at .

 

Also, check this: "Understanding Solar Indices" from September 2002 QST.

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/EX

 

 

 

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