[Ips-dsgr] ASWFC Daily Report - 23 July 24 issued 2342 UT on 23 Jul 2024 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Jul 24 09:42:16 AEST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 JULY 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 23 JULY AND FORECAST FOR 24 JULY - 26 JULY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
Comment: Reissued to correct text in solar comment.
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1A. SOLAR SUMMARY
Activity 23 Jul: R1
Flares Max Fadeout Freq. Sectors
M2.4 1428UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 23 Jul: 176/130
1B. SOLAR FORECAST
24 Jul 25 Jul 26 Jul
Activity R1,chance R2 R1,chance R2 R1,chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 180/133 182/135 180/133
COMMENT: Solar activity on UT day 23-Jul was R1. Solar region
AR3764(S03E72, beta-gamma) has recently rotated onto the visible
solar disk. Optical flare emission was observed from AR3751(S08W51,
beta-gamma) and near the trailer spots of AR3764 at/near the
time of the slow rise and fall M2.4 X-ray flare, making region
assignment of this flare somewhat ambiguous. Solar region AR3762(S13E28,
beta-gamma-delta) is the largest and most magnetically complex
region currently on the solar disk and produced C class flares.
Solar region AR3762 has shown redistribution in its trailer spots
and a decline in its intermediate spots with slight growth evident
in its leader spots. Solar region AR3761(S10W38, beta) and AR3751
appear to be in slow decline. There are currently ten numbered
sunspots on the solar disk. Other regions are small and stable.
Solar activity is expected to be R1, chance R2 over 24-26 Jul.
No Earth directed CMEs have been observed in the past 24 hours.
A large and fast far side CME was observed from 23/0036UT in
LASCO C2 imagery. A southwest directed CME was observed from
23/0424UT which is possibly associated with on disk activity.
There was some localised on disk plasma motion to the south and
west of AR3761 but the motion is considered small and occurring
at 23/0408UT, quite close to the CME first observation time.
Event analysis showed low confidence pairing between LASCO and
STEREO-A views. Event modelling was conducted assuming the on
disk activity was associated with the slow CME showing an Earth
miss with the CME passing ahead of the Earth. S1 solar radiation
storm conditions were observed from 23/0200UT and the proton
flux is currently declining to the S1 event threshold and is
expected to end on 24-Jul. A 100MeV solar proton event was also
briefly observed. This proton event followed the far side CME.
S0 solar radiation storm conditions are expected over 25-26 Jul.
The solar wind speed on UT day 23-Jul was slow with a declining
trend until 23/1949UT when a weak shock was observed. This shock
arrived earlier than expected and the increase in solar wind
speed was only slight and is believed associated with the M1
flare/filament eruption on 21-Jul. The solar wind speed ranged
between 246 to 333 km/s and is currently near 317 km/s. The peak
total interplanetary field strength (IMF, Bt) was 17 nT and the
north-south IMF component range was +8 to -3 nT. The solar wind
IMF became enhanced and swung northwards post shock arrival,
an orientation associated with reduced induced geomagnetic activity.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 23 Jul: G0
Estimated Indices 23 Jul : A K
Australian Region 2 11100021
Cocos Island 3 12110021
Darwin 3 11100032
Townsville 4 12100032
Learmonth 2 11101021
Alice Springs 2 10100021
Gingin 1 01100020
Canberra 1 00000021
Kennaook Cape Grim 0 00000020
Hobart 1 10000020
Estimated Antarctic Regional K Indices 23 Jul :
Macquarie Island 0 00000010
Casey 2 01110022
Mawson 2 21101011
Observed Regional daily pc3 Indices 23 Jul :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 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 Jul : A
Fredericksburg 6
Planetary 7
Observed AFr/Ap Indices 22 Jul : A K
Fredericksburg 9
Planetary 8 1223 2322
2B. MAGNETIC FORECAST
Date Ap Conditions
24 Jul 16 G0, chance G1
25 Jul 10 G0
26 Jul 8 G0
COMMENT: ASWFC Geomagnetic Warning 33 was issued on 21 July and
is current for 24-25 Jul. G0 Geomagnetic conditions were observed
in the Australian and Antarctic region on UT day 23-Jul. Weaker
geomagnetic activity is now expected on 24-Jul with G0, chance
G1 geomagnetic conditions now considered more likely due to sustained
northward IMF orientation post CME shock arrival. Generally G0
conditions expected for 25-26 Jul.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
23 Jul Normal Normal Fair-poor
PCA Event : 10MeV Proton/PCA Event Began 23 07 2024 0250UT and is in progress
and, 100MeV Proton/PCA Event Began at 0200UT 23/07, Ended at 1300UT 23/07
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
24 Jul Normal Normal-fair Poor(PCA)
25 Jul Normal Normal Normal-fair
26 Jul Normal Normal Normal-fair
COMMENT: HF radio communication conditions on UT day 23-Jul were
degraded at high latitudes due to increased absorption from a
S1-Minor solar radiation storm. Low to middle latitude HF conditions
were generally near normal, with equatorial spread F observed
at Niue 23/0900-0930UT. Degradations for middle to high latitudes
that were expected on 24-25 Jul due to anticipated geomagnetic
activity from a CME are now expected to be much more mild. Isolated
minor HF fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
23 Jul 146
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 25% during local day.
Enhanced by 65% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 45% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Southern Australian Region:
Enhanced by 15-20%.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Proton event in progress, increased absorption observed.
Monthly T index:
Month T index
Jun 120
Jul 118
Aug 117
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
24 Jul 125 Near predicted monthly values to 15% enhanced
25 Jul 125 Near predicted monthly values to 15% enhanced
26 Jul 125 Near predicted monthly values to 15% enhanced
COMMENT: ASWFC Preliminary HF Communications Warning 77 was issued
on 22 July and is current for 24-25 Jul. ASWFC SWF HF Communications
Warning 78 was issued on 22 July and is current for 23-25 Jul.
Maximum usable frequencies (MUFs) on UT day 23-Jul were near
predicted values to 20% enhanced in the Australian region. Strong
spread-F was observed at Hobart during local night hours. Ionospheric
scintillation was observed at Niue 23/0710-0937UT. MUFs are expected
to be near predicted values to 15% enhanced over 24-26 Jul. Degraded
HF conditions for local night on 24-Jul and brief depressions
for southern Australian region early on 25-Jul are now not expected
due to much weaker/earlier than expected geomagnetic activity
from a recent CME. Isolated minor HF fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 22 Jul
Daily Proton Fluence >1 MeV: 5.3E+05
Daily Proton Fluence >10 MeV: 2.2E+04
Daily Electron Fluence >2 MeV: 9.60E+05 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.2
DSCOVR Satellite Solar Wind Day Averaged Data for 22 Jul
Speed: 294 km/sec Density: 1.6 p/cc Temp: 15900 K Bz: -5 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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