[Ips-dsgr] ASWFC Daily Report - 20 May 24 issued 2330 UT on 20 May 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Tue May 21 09:30:48 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 MAY 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 MAY AND FORECAST FOR 21 MAY - 23 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 May: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 May: 200/152
1B. SOLAR FORECAST
21 May 22 May 23 May
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 200/152 200/152 200/152
COMMENT: Solar activity on UT day 20-May was R0. Solar region
AR3685(S14E19, beta) is currently the largest region on
the visible solar disk. This region has shown some penumbral
decay in its intermediate spots. Smaller solar region AR3686(S08E31,
beta-gamma) has shown minor growth. Solar region AR3679(S12W31,
beta) has shown development in its trailer spots. AR3684(S06E01,
beta) has shown minor growth. A relatively small 15 degree long
solar filament erupted at 20/0554-0605UT located at S33W60-S22W65
visible in Learmonth GONG imagery. The filament was near solar
region AR3683(S23W68, beta) and was associated with a minor C6.7
flare at 20/0554UT. There are currently seven numbered sunspot
regions visible on the solar disk. All other sunspot regions
are either stable or in decay. Solar activity is expected to
be at R0-R1 levels over 21-23 May. A coronal mass ejection was
observed with the filament eruption at S30W60 near region AR3683.
The CME associated with the filament eruption appeared to be
to the south and west, and was surrounded by either shock wave
structure or a simultaneous presumed far side CME. Event modelling
assuming a more narrow and south west CME rather than the expansive
overall envelope shows a possible weak CME arrival on 23-May
at 1700UT +/- 12 hours, with the bulk of the CME passing ahead
and under the Earth. However, further analysis of the event will
be conducted. The size of the filament and far west longitudinal
location, together with the lack of on any on disk shock wave/diming
across the solar disk, with only localised plasma motion southward
visible in SDO imagery, suggests reduced geo-effectiveness for
this event. The solar wind speed on UT day 20-May was mostly
steady, ranging from 327 to 427 km/s and is currently near 385
km/s. The peak total interplanetary field strength (IMF, Bt)
was 9 nT and the north-south IMF component (Bz) range was +7
to -6 nT. A coronal hole is visible in the northern solar hemisphere
centered at N50E10, the high solar latitude of this hole is expected
to reduce the influence on the solar wind near the Earth.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 May: G0
Estimated Indices 20 May : A K
Australian Region 5 13302001
Cocos Island 4 12312000
Darwin 6 23312001
Townsville 6 23312002
Learmonth 7 23402001
Alice Springs 5 23302001
Gingin 5 13302000
Canberra 3 12202001
Kennaook Cape Grim 4 12302001
Hobart 3 12202001
Estimated Antarctic Regional K Indices 20 May :
Macquarie Island 2 01301000
Casey 8 24301112
Mawson 12 14522101
Observed Regional daily pc3 Indices 20 May :
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 20 May : A
Fredericksburg 15
Planetary 21
Observed AFr/Ap Indices 19 May : A K
Fredericksburg 10
Planetary 9 2313 3222
2B. MAGNETIC FORECAST
Date Ap Conditions
21 May 8 G0
22 May 6 G0
23 May 18 G0, chance G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 20-May. Mostly G0 geomagnetic conditions were
observed in the Antarctic region, with an isolated period of
G1 observed at Mawson. G0 geomagnetic conditions are expected
over 20-22 May, there is a chance for G1 periods on 23-May due
to a glancing blow from a recent CME.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 May Normal Normal-fair Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 May Normal Normal Normal-fair
22 May Normal Normal Normal
23 May Normal Normal-fair Fair
COMMENT: HF radio communication conditions on UT day 20-May were
mostly normal. Mostly normal HF conditions are expected over
21-23 May. Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 May 146
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 35% during local day.
Enhanced by 15% during local night.
Enhanced by 20% after local dawn.
Niue Island Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Enhanced by 40% during local night.
Southern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 25% over the UT day.
Monthly T index:
Month T index
Apr 125
May 114
Jun 116
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
21 May 145 Near to 15% above predicted monthly values
22 May 145 Near to 15% above predicted monthly values
23 May 145 Near to 15% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 54 was issued on
19 May and is current for 20-22 May. Maximum usable frequencies
(MUFs) on UT day 20-May were near predicted monthly values to
40% enhanced. Spread F was observed at Hobart during local night
hours. Weak ionospheric phase scintillation was observed at Darwin
20/08-14UT. MUFs are expected to be near predicted monthly values
to 15% enhanced over 21-23 May. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 May
Daily Proton Fluence >1 MeV: 7.0E+06
Daily Proton Fluence >10 MeV: 4.4E+04
Daily Electron Fluence >2 MeV: 9.70E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 19 May
Speed: 391 km/sec Density: 2.4 p/cc Temp: 35900 K Bz: -3 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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