[Ips-dsgr] ASWFC Daily Report - 26 September 23 issued 2334 UT on 26 Sep 2023 [SEC=OFFICIAL]
rwc
rwc at ips.gov.au
Wed Sep 27 09:34:30 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 26 SEPTEMBER AND FORECAST FOR 27 SEPTEMBER - 29 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 26 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Sep: 165/119
1B. SOLAR FORECAST
27 Sep 28 Sep 29 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 168/122 168/122 162/116
COMMENT: Solar activity on UT day 26-Sep was at the R0 level.
Solar region AR3445(S13W16, gamma) which consists of numerous
small spots, is showing growth in its southern region spots,
and produced several mid range C class flares. The intermediate
and trailer spots of region AR3435(N10W49, beta-gamma) which
last produced R1 activity on 22-Sep, are now in decay. Solar
region AR3447(S22W00, beta) continues to grow. Solar region AR3448(N14E62,
alpha) consists of a large single quiet spot, nearby a new currently
small region AR3449(N15E50, beta) which currently consists of
small spots continues to emerge. Solar region AR3443(N25W76,
alpha) is rotating off disk, with trailer spots remaining just
visible. Other regions are currently small. There are currently
9 numbered regions and one unnumbered region on the solar disk.
Solar activity over 27-29 Sep is expected to be R0-R1, with the
slight chance of an R2 flare. No significantly Earth directed
CMEs have been observed. A data gap in LASCO imagery from 25/1400-2313UT
prevents confirmation of any associated CME with yesterdays filament
eruption at N25W55 which erupted at 25/1537UT. The reasonably
far western location of the filament implies that the geo-effectiveness
of any associated CME is likely to be minimal. The solar wind
speed on UT day 26-Sep was moderately elevated, ranging from
418 km/s to 532 km/s. The wind speed was generally near 450km/sec
for the first half of the UT day, a gradual increase was observed
after 26/1100UT and is currently near 500km/sec. The peak total
interplanetary field strength (IMF, Bt) was 16 nT and the north-south
IMF component range was +11 to -12 nT. A period of sustained
southward IMF conditions of approximately -11nT was observed
26/0430-1100UT. The solar wind IMF which was recently enhanced
due to a CME, continues to decline. Two small coronal holes are
visible in SDO211 imagery, located at N35E15 and N05E52.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 26 Sep: G1
Estimated Indices 26 Sep : A K
Australian Region 18 23345332
Cocos Island 16 -3325331
Darwin 13 23334322
Townsville 17 23344432
Learmonth 18 23335432
Alice Springs 15 13335322
Gingin 21 23345433
Canberra 15 13344332
Hobart 22 23455332
Estimated Antarctic Regional K Indices 26 Sep :
Macquarie Island 40 13665622
Casey 21 44433433
Mawson 63 44534677
Observed Regional daily pc3 Indices 26 Sep :
Darwin 2 (Quiet)
Townsville 0 (Quiet)
Learmonth 4 (Quiet)
Alice Springs 2 (Quiet)
Gingin 7 (Quiet)
Canberra 0 (Quiet)
Hobart 2 (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 26 Sep : A
Fredericksburg 26
Planetary 33
Observed AFr/Ap Indices 25 Sep : A K
Fredericksburg 15
Planetary 21 5433 4322
2B. MAGNETIC FORECAST
Date Ap Conditions
27 Sep 11 G0, slight chance of G1
28 Sep 9 G0
29 Sep 12 G0, slight chance of G1
COMMENT: ASWFC Geomagnetic Warning 58 was issued on 24 September
and is current for 25-27 Sep. G1 periods were observed in the
Australian region on UT day 26-Sep. In the Antarctic region G0
conditions were observed at Casey, G1-G2 periods at Macquarie
Island, G1-G3 conditions were observed at Mawson. The increase
in geomagnetic activity was in associated with an extended interval
of southward solar wind IMF conditions. G0 geomagnetic conditions
are generally expected over 27-29 Sep, with the slight chance
of an mild increase in geomagnetic activity associated with weak
glancing blows from recent CMEs.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 Sep Normal Normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 Sep Normal Fair-normal Fair-normal
28 Sep Normal Normal Normal
29 Sep Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 26-Sep were
mostly normal. Generally normal HF propagation conditions are
expected over 27-29 Sep. Fair conditions may be briefly experienced
after local dawn for middle to high latitudes on 27-Sep. Isolated
minor shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 Sep 129
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values.
Niue Island Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Enhanced by 20% after local dawn.
Northern Australian Region:
Enhanced by 15% during local day.
Enhanced by 30% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 25% 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
27 Sep 95 Depressed 10 to 15%/near predicted monthly values
28 Sep 115 10 to 15% above predicted monthly values
29 Sep 115 10 to 15% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 100 was issued on
24 September and is current for 25-27 Sep. Maximum usable frequencies
(MUFs) in the Australian region on UT day 26-Sep were near predicted
monthly values to 30% enhanced. Spread F was observed at Hobart
last night and MUFs at Hobart are depressed 15-20% after local
dawn this morning, following mild overnight geomagnetic activity.
Other southern region sites are currently near normal. MUFs are
generally expected to be near monthly predicted values to 15%
enhanced over 27-29 Sep, with brief mild depressions early in
the UT day on 27-Sep for the southern Australian region. Isolated
minor shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 Sep
Daily Proton Fluence >1 MeV: 2.8E+07
Daily Proton Fluence >10 MeV: 2.5E+04
Daily Electron Fluence >2 MeV: 1.10E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.5
DSCOVR Satellite Solar Wind Day Averaged Data for 25 Sep
Speed: 463 km/sec Density: 17.8 p/cc Temp: 65900 K Bz: 9 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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