[Ips-dsgr] ASWFC Daily Report - 15 September 24 issued 2330 UT on 15 Sep 2024 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Mon Sep 16 09:30:57 AEST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/15 SEPTEMBER 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 15 SEPTEMBER AND FORECAST FOR 16 SEPTEMBER - 18 SEPTEMBER
STATUS INDICATORS SOL:** RED ** MAG:** RED ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 15 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 15 Sep: 173/127
1B. SOLAR FORECAST
16 Sep 17 Sep 18 Sep
Activity R1, chance R2/R3 R1, chance R2/R3 R1, chance R2/R3
Fadeouts Probable Probable Probable
10.7cm/SSN 175/129 170/124 170/124
COMMENT: Solar activity on UT day 15-Sep was at the R0 level
with multiple C-class flares. There are currently five numbered
sunspot regions visible on the solar disk and one unnumbered
region. AR3825 (S15E41, gamma) is the largest and most significant
group on the solar disk, however it underwent some spot decay
over the UT day and lost its delta spot. AR3824 (S04W20, beta-gamma)
developed over the UT day. An unnumbered region has recently
rotated onto the solar disk at around S25E75 with alpha magnetic
complexity and appears stable. All other sunspot regions are
either stable or in decay. Solar activity is expected to be at
the R1 level over 16-18 Sep, with a chance of R2-R3 events. The
>10MeV solar proton flux was elevated over the UT day but did
not cross the S1 threshold. S0 conditions, with a chance of S1
are expected over 16-18 Sep. No CMEs were observed over the UT
day. The solar wind speed on UT day 15-Sep was steady but choppy,
ranging from 426 to 570 km/s and is currently near 440 km/s.
The peak total interplanetary field strength (IMF, Bt) was 9
nT and the north-south IMF component (Bz) range was +6 to -8
nT. A significant increase in wind speed is expected on 16-Sep
due to an anticipated impact from a fast halo CME, first observed
on 14-Sep, around the middle of the UT day. This is expected
to combine with a possible glancing impact from a CME first observed
on 13-Sep and high speed wind stream effects from coronal holes
in the northern and southern hemisphere. The solar wind speed
is expected to continue to be elevated on 17-Sep, with a decline
towards background levels possible on 18-Sep
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 15 Sep: G0
Estimated Indices 15 Sep : A K
Australian Region 11 23323322
Cocos Island 7 23222221
Darwin 10 23323222
Townsville 13 23323333
Learmonth 12 23333322
Alice Springs 10 23323222
Gingin 12 23323332
Canberra 10 13313223
Kennaook Cape Grim 12 13323333
Hobart 14 23423333
Estimated Antarctic Regional K Indices 15 Sep :
Macquarie Island 25 34535432
Casey 17 44433223
Mawson 29 34534454
Observed Regional daily pc3 Indices 15 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 8 (Quiet)
Canberra 11 (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 15 Sep : A
Fredericksburg 17
Planetary 20
Observed AFr/Ap Indices 14 Sep : A K
Fredericksburg 22
Planetary 23 3325 5433
2B. MAGNETIC FORECAST
Date Ap Conditions
16 Sep 65 G3, chance of G4
17 Sep 25 G0-G1, chance of G2
18 Sep 15 G0, chance of G1
COMMENT: ASWFC Geomagnetic Warning 55 was issued on 14 September
and is current for 15-17 Sep. G0 geomagnetic conditions were
observed in the Australian region on UT day 15-Sep. Mostly G1
geomagnetic conditions were observed in the Antarctic region
with G0 conditions observed at Casey. G3 geomagnetic conditions,
with a chance of G4 are expected on 16-Sep, due to an anticipated
impact from a halo CME first observed on 14-Sep, combined with
a possible glancing impact from a CME first observed on 13-Sep
and high speed wind stream effects from coronal holes in the
northern and southern hemispheres. G0-G1 geomagnetic conditions,
with a chance of G2 are expected on 17-Sep and G0 conditions,
with a chance of G1 are expected on 18-Sep, due to ongoing CME
and coronal hole high speed wind stream effects.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
15 Sep Poor-normal Fair-normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
16 Sep Poor Poor Poor
17 Sep Fair Fair Fair-poor
18 Sep Normal Normal Normal-fair
COMMENT: HF radio communication conditions on UT day 15-Sep were
mostly poor at high latitudes and fair at mid to low latitudes
until around 1200UT when conditions eased to mostly normal at
all latitudes. Degraded conditions are likely in the second half
of 16-Sep due to anticipated geomagnetic activity. Possible S1
solar proton conditions may also cause degradations to HF conditions
at high latitudes. Conditions are expected to remain degraded
on 17-Sep, with a recovery to mostly normal conditions expected
on 18-Sep. Shortwave fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
15 Sep 125
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 15% during local day.
Enhanced by 45% during local night.
Niue Island Region:
Enhanced by 35% during local day.
No data available during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Southern Australian Region:
Near predicted monthly values during local day.
Depressed by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 159
Sep 117
Oct 116
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
16 Sep 100 Depressed 5 to 20%/near predicted monthly values
17 Sep 130 Near predicted monthly values
18 Sep 130 Near predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 102 was
issued on 14 September and is current for 16-17 Sep. Maximum
usable frequencies (MUFs) in the northern Australian region on
UT day 15-Sep were near predicted monthly values. MUFs in the
southern Australian region were near predicted monthly values
to depressed by up to 20%, with the strongest depressions observed
during local night hours. Spread F was observed at Hobart throughout
the day, and at Perth, Canberra and Brisbane during local night.
MUFs on 16-Sep are expected to be near predicted monthly values
for the first part of the day. Following expected geomagnetic
activity in the middle of the day, depressions of up to 20% are
expected particularly in the southern Australian region. MUFs
are expected to continue to be depressed on 17-Sep, with a recovery
towards near predicted monthly values possible on 18-Sep. Shortwave
fadeouts are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 14 Sep
Daily Proton Fluence >1 MeV: 2.0E+06
Daily Proton Fluence >10 MeV: 6.6E+04
Daily Electron Fluence >2 MeV: 2.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 4%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.5
DSCOVR Satellite Solar Wind Day Averaged Data for 14 Sep
Speed: 420 km/sec Density: 2.4 p/cc Temp: 66800 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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