[Ips-dsgr] ASWFC Daily Report - 18 May 23 issued 2331 UT on 18 May 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Fri May 19 09:31:24 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 MAY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 MAY AND FORECAST FOR 19 MAY - 21 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 18 May: R1
Flares Max Fadeout Freq. Sectors
M1.0 0626UT possible lower Mid East/Indian
M1.2 0655UT possible lower Mid East/Indian
M2.2 1147UT possible lower European
M1.1 1751UT possible lower South American/
Atlantic
M3.8 2023UT possible lower East Pacific/
North American
M4.5 2105UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 May: 151/106
1B. SOLAR FORECAST
19 May 20 May 21 May
Activity R1, chance of R2 R1, chance of R2 R1, chance of R2
Fadeouts Possible Possible Possible
10.7cm/SSN 145/99 140/94 140/94
COMMENT: Solar activity on UT day 18-May was at the R1 level
with five M-class flares observed. An M1 flare at 18/0626UT,
an M1.2 flare at 18/0655UT, a multipeak M2.2 flare at 18/1147UT,
an M1.1 flare at 18/1751UT and a multipeak M4.5 flare at 18/2105UT.
All of the M-class flares of the day were produced by newly numbered
AR3311 (N18E74, beta). There are currently eight numbered sunspot
regions on the solar disk. AR3305 (N08W41, beta-gamma-delta),
AR3307 (S09W07, beta) and AR3308 (N11W27, beta) all displayed
spot development over 18-May. Newly arrived region AR3311 is
the most significant active region on the solar disk due to a
history of M-class flares of increasing magnitude. AR3310 (S20E58,
beta), which produced an M9.6 flare on 16-May appears stable
and has produced no flares above the C-class level since then.
Solar activity is expected to be at the R1 level over 19-21 May,
with a chance of R2. Several CMEs were observed on 19-May, but
none are considered geoeffective. Three west directed CMEs were
observed in LASCO and STEREO-A imagery. A narrow CME from 18/0336UT
associated with an eruption on the west limb at around N24 observed
from 18/0308UT in SDO, H-Alpha and GOES SUVI imagery, no STEREO-A
imagery is available for this CME an it is considered not geoeffective.
The second is a faint partial halo directed broadly to the west
visible from 18/0812UT. No on disk activity is associated with
this event and modelling suggests it is a far side event with
no geoeffective component. Lastly a southwest directed CME is
visible from 18/1709UT, no on disk activity is associated with
this event. Modelling suggests this CME will pass ahead of the
Earth with no geoeffective component. Two filament lift offs
were observed in SDO, GOES SUVI and H-Alpha imagery over the
UT day. One from 18/0238UT at around S70E10 to S70W50 although
it may continue over the limb. The other from 18/1628UT in the
north east quadrant from around N20E30 to N35E50. No associated
CMEs are visible in coronagraph imagery from either of these
events. A CME observed on 17-May has been further analysed to
have the chance of a glancing impact with Earth on 21-May. 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 18-May, ranging from 403 to 501 km/s and is currently at
around 470 km/s. The peak total interplanetary field strength
(IMF, Bt) was 4 nT and the north-south IMF component (Bz) range
was 4 to -3 nT. The solar wind speed is expected to remain steady
over 19-20 May. An increase is expected on 21-May due to a pair
of coronal holes in the southern hemisphere which are rotating
towards a geoeffective position. In addition, there is a chance
of a glancing impact on 21-May from a CME first observed on 17-May.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 May: G0
Estimated Indices 18 May : A K
Australian Region 0 11000000
Cocos Island 1 11010000
Darwin 1 11100001
Townsville 2 11100012
Learmonth - --------
Alice Springs 0 00000000
Gingin 0 10000000
Canberra 0 01000000
Hobart 0 01000000
Estimated Antarctic Regional K Indices 18 May :
Macquarie Island 0 00000000
Casey 2 22100000
Mawson 3 32200000
Observed Regional daily pc3 Indices 18 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth NA
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 18 May : A
Fredericksburg 4
Planetary 4
Observed AFr/Ap Indices 17 May : A K
Fredericksburg 5
Planetary 4 1100 1121
2B. MAGNETIC FORECAST
Date Ap Conditions
19 May 5 G0
20 May 5 G0
21 May 15 G0, chance of G1
COMMENT: G0 geomagnetic conditions were observed in both the
Australian and Antarctic regions on UT day 18-May. G0 geomagnetic
conditions are expected over 19-20 May. G0 geomagnetic conditions
with a chance of G1 are expected on 21-May due to the combined
effects of coronal hole high speed wind streams and a possible
glancing impact from a CME first observed on 17-May.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 May Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 May Normal Normal Normal
20 May Normal Normal Normal
21 May Normal Normal Normal-fair
COMMENT: Mostly normal HF propagation conditions were observed
on 18-May. Normal HF propagation conditions are expected over
19-21 May. Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 May 89
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 30% during local night.
Northern Australian Region:
Near predicted monthly values.
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
19 May 90 Near predicted monthly values
20 May 95 Near predicted monthly values
21 May 95 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 46 was issued on
18 May and is current for 18-20 May. Maximum usable frequencies
(MUFs) on UT day 18-May were near predicted monthly values in
the Australian region. Spread-F was observed at Darwin and Hobart
during local night hours. Small amounts of sporadic E were observed
across the Australian region. MUFs are expected to be near predicted
monthly values over 19-21 May. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 May
Daily Proton Fluence >1 MeV: 1.7E+05
Daily Proton Fluence >10 MeV: 4.3E+04
Daily Electron Fluence >2 MeV: 2.70E+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 17 May
Speed: 430 km/sec Density: 4.0 p/cc Temp: 133000 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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