ARLP038 Propagation de K7RA

 

SB PROP @ ARL $ARLP038

ARLP038 Propagation de K7RA

 

ZCZC AP38

QST de W1AW

Propagation Forecast Bulletin 38 ARLP038

From Tad Cook, K7RA

Seattle, WA October 4, 2024

To all radio amateurs

 

SB PROP ARL ARLP038

ARLP038 Propagation de K7RA

 

ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0042UT/04 OCTOBER

2024 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.

 

Two coronal mass ejections first observed on 01-Oct and 03-Oct are

expected to impact Earth over 04-05 Oct. Lack of analyzable corona

graph imagery makes arrival time predictions uncertain.

 

INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION

FROM 04-06 OCTOBER 2024.

 

GEOMAGNETIC ACTIVITY FORECAST:

04 Oct: G3, chance of G4

05 Oct: G3, chance of G4

06 Oct: G1-G2

 

New sunspot groups emerged on every day over the past week. Two new

regions appeared on September 26, another on September 27, two more

on September 28, another on September 29, another on September 30,

three more on October 1 and another on October 2, for a total of

eleven.

 

Average daily sunspot number rose from 137.1 to 164.7, and average

daily solar flux from 164.3 to 213.1. Average daily planetary A

index shifted from 14.3 to 9.6.

 

Predicted solar flux is 310 on October 4-6, 300 on October 7, 290 on

October 8-10, 175 on October 11-16, 170 on October 17-21, then 175,

180, 185, 190 and 195 on October 22-26, then 200 on October 27-29,

205 on October 30 through November 4, then 200 and 185 on November

5-6 and 175 on November 7-12.

 

Predicted planetary A index is 54, 94, 72, 22 and 15 on October 4-8,

5 on October 9-10, then 20 and 19 on October 11-12, then 5 on

October 13-21, then 28 and 10 on October 22-23, 5 on October 24-26,

and 10 on October 27, then 5 on October 28-31, 10 on November 1-2, 5

on November 3-5, then 10, 20, and 19 on November 6-8, and 5 on

November 9 and the foreseeable future.

 

"Weekly Commentary on the Sun, the Magnetosphere, and the Earth's

Ionosphere - October 3, 2024 from OK1HH:

 

"After AR3811 disappeared from our field of view behind the

southwestern limb of the solar disk on September 12, it was

continuously tracked by helioseismological methods until September

29, when it reappeared in the southeast, numbered AR3842. Its size

and activity on the far side of the Sun suggested that we could look

forward to a lot of activity in October.

 

"And so, it did. When solar flare X7.1/2b was observed on October 1

with a maximum at 2220 UT, the second largest in the current 11-year

cycle, I planned to start with this announcement. But when flare

X9.05, newly the largest in X-ray intensity in the same AR3842, was

observed on October 3 at 1218 UT, that was no longer the case.

 

"The source region of AR3842 was heading straight towards us. So,

the plasma cloud was probably heading directly for our ionosphere.

Unlike the aforementioned X7.1/2b (which thus moved to the third

largest), it is very likely that the CME of October 3 will hit

Earth. We therefore expect a disrupted end of the week.

 

"This weekend we can expect low MUF and high LUF on shortwave and

QSOs over aurora on VHF. Early next week will see a gradual return

to average and then above average radio wave propagation conditions

in the ionosphere."

 

From "The New Zealand Herald," Aurora in Auckland:

 

 

Radio Blackout hits U.S.:

 

 

 

Here is the latest update from Dr. Tamitha Skov, WX6SWW:

 

 

Send your tips, reports, observations, questions and comments to

. When reporting observations, don't forget to tell us

which mode you were operating.

 

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

.

 

An archive of past propagation bulletins is at

. More good

information and tutorials on propagation are at .

 

Also, check this article:

 

 

"Understanding Solar Indices" from September 2002 QST.

 

Instructions for starting or ending email subscriptions to ARRL

bulletins are at .

 

Sunspot numbers for September 26 through October 2 2024 were 189,

122, 148, 154, 150, 196, and 194, with a mean of 164.7. 10.7 cm flux

was 181.1, 186, 194.5, 197.2, 214.2, 244.6, and 274.4, with a mean

of 213.1. Estimated planetary A indices were 13, 7, 7, 16, 11, 6,

and 7, with a mean of 9.6. Middle latitude A Index was 11, 5, 5, 17,

5, 9, and 6, with a mean of 8.3.

NNNN

/EX

 


ARRL® The National Association for Amateur Radio®