[Ips-dsgr] ASWFC Daily Report - 17 May 23 issued 2330 UT on 17 May 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Thu May 18 09:30:09 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 MAY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 MAY AND FORECAST FOR 18 MAY - 20 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 May: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 May: 138/92
1B. SOLAR FORECAST
18 May 19 May 20 May
Activity R1, chance of R2 R1, chance of R2 R1, chance of R2
Fadeouts Possible Possible Possible
10.7cm/SSN 140/94 138/92 135/89
COMMENT: Solar activity on UT day 17-May was at the R0 level.
Several C-class flares were observed, the largest being a C9.5
flare produced at 17/2148UT from an active region currently beyond
the east limb at around N18. There are currently seven numbered
sunspot regions on the solar disk. AR3308 (N11W14, beta) has
shown spot development over the UT day. All other sunspot regions
are either stable or in decay. Newly numbered AR3310 (S20E72,
beta) is the largest and most significant active area on the
solar disk, with a history of M-class flares, this active region
may be returning region AR3288 which was expected to return on
18-May at S22. Also significant is the presence of an active
region producing many C-class flares over the eastern limb at
around N18. Solar activity is expected to be at the R1 level
over 18-20 May, with a chance of R2. Several CMEs were observed,
but none are considered geoeffective. Multiple west directed
CMEs were observed and modelled, all of which are considered
to be missing the Earth. A recent west directed CME was observed
from 17/1923UT in LASCO C2 and STEREO-A imagery. Modelling was
performed with limited imagery and suggests this CME will miss
Earth. Further analysis will be performed when more imagery is
available. A slight enhancement in the 10 MeV proton flux is
currently underway as a result of an M9.6 flare from 16-May,
this is not expected to breach the S1 threshold. The solar wind
speed decreased slightly over 17-May, with an increase observed
from 17/1900UT ranging from 409 to 465 km/s and is currently
at around 435 km/s. The peak total interplanetary field strength
(IMF, Bt) was 6 nT and the north-south IMF component (Bz) range
was 5 to -3 nT. The solar wind speed is expected to slowly decline
to background levels over 18-20 May.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 May: G0
Estimated Indices 17 May : A K
Australian Region 1 11100001
Cocos Island 1 11110000
Darwin 1 11100001
Townsville 2 11100012
Learmonth 3 1-------
Alice Springs 1 10100001
Gingin 2 22100010
Canberra 0 01000001
Hobart 0 01000000
Estimated Antarctic Regional K Indices 17 May :
Macquarie Island 0 10000000
Casey 6 33221010
Mawson 4 32100012
Observed Regional daily pc3 Indices 17 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 168 (Severe storm)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 4 (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 17 May : A
Fredericksburg 4
Planetary 5
Observed AFr/Ap Indices 16 May : A K
Fredericksburg 10
Planetary 9 3231 1222
2B. MAGNETIC FORECAST
Date Ap Conditions
18 May 5 G0
19 May 5 G0
20 May 5 G0
COMMENT: G0 geomagnetic conditions were observed in both the
Australian and Antarctic regions on UT day 17-May. G0 geomagnetic
conditions are expected over 18-20 May.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 May Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 May Normal Normal Normal
19 May Normal Normal Normal
20 May Normal Normal Normal
COMMENT: Mostly normal HF propagation conditions were observed
on 17-May. Normal HF propagation conditions are expected over
18-20 May. Isolated shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 May 88
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values.
Niue Island Region:
Near predicted monthly values.
Northern Australian Region:
Near predicted monthly values during local day.
Depressed by 20% 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
18 May 90 Near predicted monthly values
19 May 90 Near predicted monthly values
20 May 95 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) on UT day 17-May were
near predicted monthly values in the Australian region, with
depressions of up to 20% observed in the northern Australian
region during local night. Spread-F was observed at Canberra,
Darwin and Hobart during local night hours. Sporadic E was observed
at Perth and Cocos Islands. MUFs are expected to be near predicted
monthly values over 18-20 May. Isolated shortwave fadeouts are
possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 May
Daily Proton Fluence >1 MeV: 6.8E+04
Daily Proton Fluence >10 MeV: 2.5E+04
Daily Electron Fluence >2 MeV: 2.20E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B7.8
DSCOVR Satellite Solar Wind Day Averaged Data for 16 May
Speed: 479 km/sec Density: 7.2 p/cc Temp: 210000 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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