[Ips-dsgr] ASWFC Daily Report - 20 May 23 issued 2331 UT on 20 May 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sun May 21 09:31:25 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 MAY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 MAY AND FORECAST FOR 21 MAY - 23 MAY
STATUS INDICATORS SOL:** RED ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 May: R2
Flares Max Fadeout Freq. Sectors
M1.0 0702UT possible lower Mid East/Indian
M6.5 0732UT probable lower Mid East/Indian
M1.6 1054UT possible lower European
M8.9 1235UT probable lower European
M5.6 1500UT possible lower South American/
Atlantic
M1.1 1903UT possible lower East Pacific/
North American
M5.2 2306UT possible lower West Pacific
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 May: 170/124
1B. SOLAR FORECAST
21 May 22 May 23 May
Activity R1-R2, chance R3 R1-R2, chance R3 R1-R2, chance R3
Fadeouts Probable Possible Possible
10.7cm/SSN 168/122 160/114 155/109
COMMENT: Solar activity on UT day 20-May reached R2 levels. Eight
M-class flares were observed: M1 at 0702 UT, M6.4 at 0732 UT,
M1 at 1054 UT, M8.9 at 1234 UT, M5.6 at 1500 UT, M1.1 at 1902
UT and M5.1 at 2306 UT. All of these flares originated from AR3311
(N18E50, beta-delta), which is still the largest and most complex
sunspot region on the solar disk. AR3311 has continued to develop
its magnetic complexity over the UT day. An M1 flare was observed
at 0928 UT from AR3312 (S23E55, beta), along with C flares with
several other regions. AR3308 (N11W51, alpha) has also shown
some minor growth. All other sunspot regions are either stable
or in decay. Solar activity is expected to be at R1-R2 levels
over 21-23 May, with a chance for R3 flares, primarily due to
AR3311. No significant CMEs were observed on UT day 20-May. The
solar wind speed on UT day was on a general increasing trend
and ranged between 370 to 600 km/s, and is currently near 550
km/s. The peak total interplanetary field strength (IMF, Bt)
was 21 nT and the north-south IMF component (Bz) range was +9
to -18 nT. This increase in the solar wind parameters was likely
due to the combination of a small equatorial coronal hole wind
stream and glancing influence from a recent CME. Bz was oriented
southward for sustained periods throughout the UT day, The solar
wind speed is expected to begin to decrease over 21-22 May as
CME effects wane, but an increase is likely by 23-May due to
2 coronal hole wind streams in the southern solar hemisphere.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 May: G2
Estimated Indices 20 May : A K
Australian Region 16 43442322
Cocos Island 12 43332122
Darwin 17 44442222
Townsville 19 44442323
Learmonth 21 53442333
Alice Springs 15 43442222
Gingin 19 53432333
Canberra 13 43332322
Hobart 13 43332322
Estimated Antarctic Regional K Indices 20 May :
Macquarie Island 29 34564422
Casey 18 34442333
Mawson 56 64642267
Observed Regional daily pc3 Indices 20 May :
Darwin 0 (Quiet)
Townsville 2 (Quiet)
Learmonth 5 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 3 (Quiet)
Hobart 8 (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 May : A
Fredericksburg 24
Planetary 34
Observed AFr/Ap Indices 19 May : A K
Fredericksburg 10
Planetary 8 0001 1244
2B. MAGNETIC FORECAST
Date Ap Conditions
21 May 12 G0
22 May 8 G0
23 May 16 G0-G1
COMMENT: Mostly G0 geomagnetic conditions were observed in the
Australian region on UT day 20-May, however there was a period
of G1 observed at Learmonth and Gingin. Despite these mostly
insignificant conditions, the Australian disturbance storm time
(DST) index reached a minimum of -120 nT at 1153 UT. G0-G2 geomagnetic
conditions were observed in the Antarctic region. General planetary
conditions observed two periods of G2 at the beginning of the
UT day. This geomagnetic activity was due to a CME which arrived
at 19/2030 UT. Geomagnetic activity is expected to be at G0 levels
over 21-23 May, with possible periods of G1 by 23-May due to
two coronal hole wind streams.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 May Poor Fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 May Normal Normal-fair Normal-fair
22 May Normal Normal Normal-fair
23 May Normal Normal Normal
COMMENT: Some degraded conditions were generally observed at
all latitudes on 20-May during local night hours. Mostly normal
HF radio communication conditions are expected over 21-23 May.
Shortwave fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 May 112
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 40% during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Southern Australian Region:
Enhanced by 15% during local day.
Enhanced by 30% during local night.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Depressed by 15% over the UT day.
Monthly T index:
Month T index
Apr 120
May 87
Jun 88
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
21 May 90 Near predicted monthly values to 10% depressed
22 May 105 Near predicted monthly values to 15% enhanced
23 May 110 Near predicted monthly values to 20% enhanced
COMMENT: ASWFC SWF HF Communications Warning 47 was issued on
19 May and is current for 20-22 May. Maximum usable frequencies
(MUFs) on UT day 20-May in the Australian region were near predicted
monthly values to 30% enhanced. Spread-F was observed at Hobart,
and degraded conditions were observed at Brisbane, Darwin and
Cocos Islands. MUFs are expected to be near predicted monthly
values on 21-May with some mild depressions, then enhanced by up
to 20% over 22-23 May. Shortwave fadeouts are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 May
Daily Proton Fluence >1 MeV: 7.1E+04
Daily Proton Fluence >10 MeV: 2.5E+04
Daily Electron Fluence >2 MeV: 4.00E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.8
DSCOVR Satellite Solar Wind Day Averaged Data for 19 May
Speed: 337 km/sec Density: 3.8 p/cc Temp: 46800 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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