[Ips-dsgr] ASWFC Daily Report - 23 September 23 issued 2330 UT on 23 Sep 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sun Sep 24 09:30:49 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 23 SEPTEMBER AND FORECAST FOR 24 SEPTEMBER - 26 SEPTEMBER
STATUS INDICATORS SOL:** RED ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 23 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.9 22/2300UT possible lower West Pacific
M1.5 2043UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 23 Sep: 173/127
1B. SOLAR FORECAST
24 Sep 25 Sep 26 Sep
Activity R1-R2, chance R3 R1-R2, chance R3 R1-R2, chance R3
Fadeouts Probable Probable Probable
10.7cm/SSN 175/129 172/126 168/122
COMMENT: Solar activity on UT day 23-Sep was R1, with an M1.5
flare at 23/2043UT produced by an active region over the western
limb, most likely AR3436. There are currently eleven numbered
sunspot regions on the solar disk. AR3441 (N07W43, gamma), AR3443
(N28W54, beta-gamma) and AR3445 (S13W22, gamma-delta) are the
most magnetically complex regions on the disk, with AR3443 also
being the largest. Of these regions, AR3441 and AR3445 showed
spot development over the UT day and AR3443 showed movement in
its trailer spots, as did AR3435 (N10W11, beta). All other regions
are either stable or in decay. Solar activity over 24-26 Sep
is expected to be R1-R2, with a chance of R3. No geoeffective
CMEs were observed on 23-Sep. A south directed CME is visible
in SOHO and STEREO-A imagery from 22/2312UT. This CME is associated
with an M1.9 flare produced by AR3435 at 22/2300UT. Modelling
indicates this CME will pass to the south of Earth. The solar
wind speed on UT day 23-Sep declined, ranging from 467 to 295
km/s, and is currently at around 315 km/s. The peak total interplanetary
field strength (IMF, Bt) was 6 nT and the north-south IMF component
range was +3 to -6 nT. Increases in the solar wind speed are
likely over 24-25 Sep due to a combination of high speed wind
stream effects from a coronal hole in the northern hemisphere
(although this high speed wind stream has yet to eventuate) and
possible glancing impacts from multiple CMEs first observed on
22-Sep. The solar wind speed is expected to decline towards background
levels on 26-Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 23 Sep: G0
Estimated Indices 23 Sep : A K
Australian Region 6 12222122
Cocos Island 4 21112111
Darwin 5 12222112
Townsville 7 22232122
Learmonth 8 22223123
Alice Springs 5 11222112
Gingin 6 11222123
Canberra 6 12132122
Hobart 6 12132122
Estimated Antarctic Regional K Indices 23 Sep :
Macquarie Island 11 11154110
Casey 11 24332122
Mawson 19 33323354
Observed Regional daily pc3 Indices 23 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 4 (Quiet)
Hobart 0 (Quiet)
Pc3 pulsations are high frequency (10-45 second period) variations
of the Earths magnetic field. Daily pc3-indices are the daily sum
of 20 minute pc3-indices for that station and have been shown to be
well correlated with rejection of high resolution aeromagnetic
survey flight-line data.
NOTE: Indices may have been generated from data obtained in
cooperation with the following organisations: Geoscience Australia,
University of Newcastle Space Physics Group, Australian Government
Antarctic Division and International Center for Space Weather
Science and Education, Japan.
Estimated AFr/Ap Indices 23 Sep : A
Fredericksburg 10
Planetary 10
Observed AFr/Ap Indices 22 Sep : A K
Fredericksburg 7
Planetary 10 1033 3332
2B. MAGNETIC FORECAST
Date Ap Conditions
24 Sep 18 G0-G1
25 Sep 16 G0, chance of G1
26 Sep 10 G0
COMMENT: ASWFC Geomagnetic Warning 56 was issued on 23 September
and is current for 23-25 Sep. G0 geomagnetic conditions were
observed in the Australian region on UT day 23-Sep. Mostly G0
geomagnetic conditions were observed in the Antarctic region,
with isolated periods of G1 at Mawson and Macquarie Island. G0-G1
geomagnetic conditions are expected on 24-Sep and G0 conditions
with a chance of G1 are expected on 25-Sep. The expected geomagnetic
activity is due to a combination of an anticipated coronal hole
high speed wind stream and multiple possible glancing impacts
from CMEs first observed on 22-Sep. G0 conditions are expected
on 26-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
23 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
24 Sep Normal Normal-fair Fair
25 Sep Normal Normal-fair Fair
26 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 23-Sep were
mostly normal. Mostly normal HF propagation conditions are expected
over 24-26 Sep, with a chance of mild degradations, particularly
at higher latitudes, over 25-26 Sep due to possible geomagnetic
activity. Shortwave fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
23 Sep 112
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Enhanced by 60% during local night.
Niue Island Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Southern Australian Region:
Mostly near predicted monthly values.
Enhanced by 20% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 115
Sep 96
Oct 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
24 Sep 110 Near predicted monthly values
25 Sep 100 Near predicted monthly values
26 Sep 100 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 98 was issued on
22 September and is current for 23-25 Sep. ASWFC Preliminary
HF Communications Warning 99 was issued on 23 September and is
current for 24-26 Sep. Maximum usable frequencies (MUFs) in the
Australian region on UT day 23-Sep were near predicted values
in the northern Australian region and near predicted monthly
values to 20% enhanced in the southern Australian region. Brief
spread-F was observed at Hobart during local night hours. MUFs
are expected to be near predicted values over 24-26 Sep, with
the possibility of mild depressions on 25-26 Sep, especially
in the southern Australian region, due to possible geomagnetic
activity. Shortwave fadeouts are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 22 Sep
Daily Proton Fluence >1 MeV: 9.0E+04
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 8.00E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 9%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 22 Sep
Speed: 403 km/sec Density: 3.9 p/cc Temp: 70100 K Bz: -2 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
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Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au
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