[Ips-dsgr] ASWFC Daily Report - 20 April 23 issued 2330 UT on 20 Apr 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Fri Apr 21 09:30:10 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 APRIL AND FORECAST FOR 21 APRIL - 23 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Apr: 147/101
1B. SOLAR FORECAST
21 Apr 22 Apr 23 Apr
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 145/99 140/94 135/89
COMMENT: Solar activity on UT day 20-Apr was at R0 levels, with
many low-level C-class flares. There are currently 4 numbered
sunspot regions on the solar disk. All regions are either stable
or in decay. AR3282 (N11W23, beta) is the largest region on the
disk and did show some small growth, but overall has been stable.
Solar activity is expected to be mostly at R0 levels over 21-23
Apr, with a small chance for isolated R1 flares. A prominence
eruption was observed to the north from 20/1446UT and a CME was
observed from the region from 20/1612UT, and was analysed not
to be geoeffective. No other CMEs were observed. The solar wind
speed on UT day 20-Apr was mostly on a declining trend to background
levels, and ranged from 450 to 366 km/s. The peak total interplanetary
magnetic field strength (IMF, Bt) was 11 nT and the north-south
IMF component (Bz) range was +10 to 0 nT. A partial halo CME
first observed on 16-Apr may arrive on 21-Apr, increasing solar
wind speeds, but confidence is low. A large coronal hole in the
southern solar hemisphere may increase solar wind speeds on 22-23
Apr, but this is low confidence due to its southern extent.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 Apr: G0
Estimated Indices 20 Apr : A K
Australian Region 4 12211201
Cocos Island 4 12211201
Darwin 5 12211212
Townsville 5 22211212
Learmonth 5 22211211
Alice Springs 3 11211201
Gingin 2 01211200
Canberra 2 11101101
Hobart 1 01100101
Estimated Antarctic Regional K Indices 20 Apr :
Macquarie Island 0 00000001
Casey 4 23210101
Mawson 3 11100113
Observed Regional daily pc3 Indices 20 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (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 20 Apr : A
Fredericksburg 9
Planetary 12
Observed AFr/Ap Indices 19 Apr : A K
Fredericksburg 9
Planetary 12 2114 4322
2B. MAGNETIC FORECAST
Date Ap Conditions
21 Apr 14 G0, slight chance G1
22 Apr 10 G0
23 Apr 8 G0
COMMENT: ASWFC Geomagnetic Warning 18 was issued on 17 April
and is current for 19-21 Apr. G0 Geomagnetic condition were observed
in the Australian and Antarctic regions on UT day 21-Apr. Mostly
G0 geomagnetic conditions are expected over 21-23 Apr. There
is a slight chance for an isolated period of G1 geomagnetic conditions
on 21-Apr due to a glancing impact from a CME first observed
on 16-Apr, however confidence is low.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 Apr Fair-normal Fair-normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 Apr Normal Normal-fair Fair-normal
22 Apr Normal Normal-fair Fair-normal
23 Apr Normal Normal-fair Normal-fair
COMMENT: Mostly normal HF propagation conditions were observed
on 20-Apr, with some degradations observed during local night
hours. Mostly normal HF propagation conditions are expected over
21-23 Apr, with further mild degradations possible over 21-22
Apr.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 Apr 125
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 15% during local day.
Enhanced by 50% during local night.
Niue Island Region:
Enhanced by 50% during local day.
Enhanced by 50% 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:
Enhanced by 15% during local day.
Enhanced by 25% during local night.
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
21 Apr 120 15-30% above predicted monthly values
22 Apr 115 Near predicted monthly values to 15% enhanced
23 Apr 120 15-30% above predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) on UT day 20-Apr in
the Australian region were enhanced by 15-30%. Sporadic-E was
observed at Canberra and Brisbane. Spread F was observed at Hobart.
Scintillation was observed at Niue from 0724-0840UT. MUFs are
expected to be 15-25% enhanced over 21-23 Apr, possibly tending
towards monthly predicted values on 22-Apr due to a low chance
of geomagnetic activity on 21-Apr.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 Apr
Daily Proton Fluence >1 MeV: 6.2E+04
Daily Proton Fluence >10 MeV: 2.2E+04
Daily Electron Fluence >2 MeV: 1.40E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.0
DSCOVR Satellite Solar Wind Day Averaged Data for 19 Apr
Speed: 487 km/sec Density: 7.8 p/cc Temp: 169000 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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