[Ips-dsgr] ASWFC Daily Report - 21 May 23 issued 2330 UT on 21 May 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Mon May 22 09:30:10 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 MAY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 MAY AND FORECAST FOR 22 MAY - 24 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 May: R1
Flares Max Fadeout Freq. Sectors
M5.2 20/2306UT possible lower West Pacific
M1.4 0223UT possible lower E. Asia/Aust.
M2.6 1604UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 May: 163/117
1B. SOLAR FORECAST
22 May 23 May 24 May
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 160/114 155/109 150/105
COMMENT: Solar activity on UT day 21-May reached R1 levels. An
M5 (R2) flare was observed from 20/2306 UT, but by 22/0000 UT
the X-ray flux had declined to R0 levels. On 21-May, 2 M class
flares were observed: M1 at 0222 UT and M2.5 at 1604 UT. These
flares originated from AR3311 (N18E37, beta-gamma-delta). The
intermediate spots of AR3311 have grown and this region still
maintains high flare potential. A C9.9 flare was observed from
AR3305 (N08W69, beta) on the western limb. All other sunspot
regions are either stable or in decay. Solar activity is expected
to be at R1-R2 levels over 22-24 May. A west directed CME was
observed from 21/2136 UT associated with the C9.9 flare, but
is not expected to be geoeffective. No other significant CMEs
were observed on 21-May. The solar wind speed on UT day 21-May
was enhanced at the beginning of the day due to ongoing coronal
hole effects, which waned throughout the day. The solar wind
speed began increasing again late in the UT day due to the arrival
of a recent CME. The solar wind speed ranged between 425 to 635
km/s and is currently near 580 km/s. The solar wind speed is
expected to remain elevated over 22-May due to ongoing CME effects,
and then elevated from coronal hole effects over 23-24 May. The
peak total interplanetary field strength (IMF, Bt) was 13 nT
and the north-south IMF component range was +8 to -11 nT. Bz
was oriented southward for several sustained periods since 21/1200
UT.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 May: G1
Estimated Indices 21 May : A K
Australian Region 13 22113344
Cocos Island 10 22112334
Darwin 12 22112344
Townsville 12 22122344
Learmonth 19 22223355
Alice Springs 11 12112344
Gingin 15 12113345
Canberra 12 12113344
Hobart 14 12124344
Estimated Antarctic Regional K Indices 21 May :
Macquarie Island 25 32125545
Casey 16 23223245
Mawson 28 44324455
Observed Regional daily pc3 Indices 21 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 28 (Quiet to unsettled)
Hobart 29 (Quiet to unsettled)
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 21 May : A
Fredericksburg 13
Planetary 21
Observed AFr/Ap Indices 20 May : A K
Fredericksburg 26
Planetary 30 3322 3466
2B. MAGNETIC FORECAST
Date Ap Conditions
22 May 20 G0, chance G1
23 May 14 G0-G1
24 May 26 G0-G2
COMMENT: ASWFC Geomagnetic Warning 29 was issued on 21 May and
is current for 22 May only. Mostly G0 geomagnetic conditions
were observed in the Australian region on UT day 21-May, with
2 periods of G1 at Learmonth and one at Gingin. G0-G1 geomagnetic
conditions were observed in the Antarctic region. General planetary
geomagnetic conditions were G0, with a period of G2 observed
late in the UT day due to a CME impact. Mostly G0 geomagnetic
conditions are expected on 22-May, with a chance of isolated
periods of G1 due to the ongoing CME effects. Periods of G1-G2
are possible by the end of UT day 23-May to 24-May due a large
southern coronal hole wind stream.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 May Poor Normal-fair Fair-poor
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 May Normal-fair Fair Fair-poor
23 May Normal Normal-fair Fair
24 May Fair Fair Fair-poor
COMMENT: On UT day 21-May, HF communication conditions were degraded
at low latitudes, mostly normal at mid-latitudes and mildly degraded
at high latitudes. Further degraded conditions are expected over
22-24, particularly at local night hours in high latitude regions.
The strongest degradations are expected on 24-May, following
expected geomagnetic activity from a coronal hole wind stream.
Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 May 97
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 25% during local day.
Near predicted monthly values during local night.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 30% during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values 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
22 May 85 Near predicted monthly values to 15% depressed
23 May 95 Near predicted monthly values
24 May 80 Near predicted monthly values to 15% depressed
COMMENT: ASWFC SWF HF Communications Warning 47 was issued on
19 May and is current for 20-22 May. ASWFC HF Communications
Warning 48 was issued on 21 May and is current for 22-24 May.
Maximum usable frequencies (MUFs) on UT day 21-May were near
predicted monthly values in the Australian region. Spread-F,
range-spread and sporadic-E were observed at most sites during
local night hours. Degraded conditions were observed particularly
at low-latitude sites during local night. MUFs are expected to
be near predicted monthly values to 15% depressed over 22-24
May. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 May
Daily Proton Fluence >1 MeV: 5.1E+04
Daily Proton Fluence >10 MeV: 2.2E+04
Daily Electron Fluence >2 MeV: 1.10E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.3
DSCOVR Satellite Solar Wind Day Averaged Data for 20 May
Speed: 501 km/sec Density: 3.2 p/cc Temp: 141000 K Bz: -1 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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