[Ips-dsgr] ASWFC Daily Report - 23 April 23 issued 2330 UT on 23 Apr 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Mon Apr 24 09:31:00 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 23 APRIL AND FORECAST FOR 24 APRIL - 26 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 23 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 23 Apr: 135/89
1B. SOLAR FORECAST
24 Apr 25 Apr 26 Apr
Activity R0, chance R1 R0, chance R1 R0, chance R1
Fadeouts Possible Possible Possible
10.7cm/SSN 135/89 130/84 125/78
COMMENT: Solar activity on UT day 23-Apr was at the R0 level,
with several low level C-class flares. There are currently six
numbered sunspot regions visible on the solar disk and two unnumbered
regions. AR3282 (N11W65, beta) is the largest region and was
mostly stable over the UT day. AR3284 (S09W10, alpha) and AR3285
(S19E45, beta) have both exhibited minor spot growth. Unnumbered
regions are visible in the southeast solar quadrant at S12E57
(alpha) and S25E75 (alpha). Both unnumbered regions are so far
unremarkable and generally stable. All other sunspot regions
are either stable or in decay. Solar activity is expected to
be at the R0 level over 24-26 Apr, with a chance of R1. Several
CMEs were observed, but none are considered geoeffective. The
solar wind speed on UT day 23-Apr increased, ranging from 330
to 610 km/s, and is currently near 600 km/s. A strong shock in
the solar wind was observed at 23/1700UT, due to the arrival
of a halo CME first observed on 21-Apr. The peak total interplanetary
field strength (IMF, Bt) was 29 nT and the north-south IMF component
(Bz) range was +26 to -25 nT. An extended period of southward
IMF conditions was observed from 23/0715UT to 23/2020UT. A large
coronal hole in the southern solar hemisphere may increase solar
wind speeds on 24-Apr, but its influence is likely limited due
to its southern extent. An equatorial coronal hole is currently
approaching the central meridian and is expected to influence
the solar wind speed on 26-Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 23 Apr: G3
Estimated Indices 23 Apr : A K
Australian Region 28 22254464
Cocos Island 18 32133453
Darwin 20 21243454
Townsville 28 22254464
Learmonth 34 32154565
Alice Springs 30 11254564
Gingin 30 21254465
Canberra 30 21254465
Hobart 37 22254375
Estimated Antarctic Regional K Indices 23 Apr :
Macquarie Island 82 11276785
Casey 22 33223455
Mawson 62 43334686
Observed Regional daily pc3 Indices 23 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 7 (Quiet)
Alice Springs 2 (Quiet)
Gingin 14 (Quiet)
Canberra 29 (Quiet to unsettled)
Hobart 111 (Major storm)
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 Apr : A
Fredericksburg 39
Planetary 69
Observed AFr/Ap Indices 22 Apr : A K
Fredericksburg 6
Planetary 7 2310 1222
2B. MAGNETIC FORECAST
Date Ap Conditions
24 Apr 35 G1-G2
25 Apr 12 G0
26 Apr 8 G0
COMMENT: ASWFC Geomagnetic Warning 19 was issued on 21 April
and is current for 23-24 Apr. G4 planetary geomagnetic conditions
were observed on UT day 23-Apr. Mostly G2 geomagnetic conditions
were observed in the Australian region, with an isolated period
of G3 observed at Hobart. G4 geomagnetic conditions were observed
in the Antarctic region. Increased geomagnetic activity observed
is due to the arrival of a halo CME first observed on 21-Apr.
G1-G2 geomagnetic conditions are expected on 24-Apr as CME impacts
abate. G0 geomagnetic conditions are expected over 25-26 Apr.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
23 Apr Normal Normal Normal
PCA Event : 10MeV Proton/PCA Event Began at 1800UT 23/04, Ended at 1900UT 23/04
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
24 Apr Fair Fair Fair-poor
25 Apr Normal Normal Normal-fair
26 Apr Normal Normal Normal-fair
COMMENT: Mostly normal HF propagation conditions were observed
on 23-Apr, with some degradations observed during local night
hours. Fair to poor HF conditions are expected on 24-Apr due
recent strong geomagnetic activity. Mostly normal HF propagation
conditions are expected over 25-26 Apr.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
23 Apr 115
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 20% during local day.
Near predicted monthly values during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 35% during local night.
Enhanced by 30% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Southern Australian Region:
Enhanced by 20% during local day.
Enhanced by 20% during local night.
Depressed by 35% after local dawn.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Mar 132
Apr 84
May 84
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
24 Apr 80 Depressed 15%/near predicted monthly values
25 Apr 95 Near predicted monthly values
26 Apr 110 Near to 15% above predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 38 was issued
on 22 April and is current for 23-24 Apr. Maximum usable frequencies
(MUFs) on UT day 23-Apr in the Australian region were enhanced
by 15-20%. MUF depressions have been observed in southern Australian
regions after local dawn due to recent increased geomagnetic
activity. Sporadic-E was observed at Learmonth. Spread F was
observed at Hobart and Perth during local night hours. MUFs are
expected to be near predicted monthly values to 15% depressed
on 24-Apr. MUFs are expected to be near predicted monthly values
to 15% enhanced over 25-26 Apr.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 22 Apr
Daily Proton Fluence >1 MeV: 4.5E+06
Daily Proton Fluence >10 MeV: 8.2E+04
Daily Electron Fluence >2 MeV: 2.50E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B7.7
DSCOVR Satellite Solar Wind Day Averaged Data for 22 Apr
Speed: 408 km/sec Density: 1.9 p/cc Temp: 74000 K Bz: 0 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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