[Ips-dsgr] ASWFC Daily Report - 27 May 23 issued 2331 UT on 27 May 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sun May 28 09:31:08 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/27 MAY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 27 MAY AND FORECAST FOR 28 MAY - 30 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 27 May: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 27 May: 157/111
1B. SOLAR FORECAST
28 May 29 May 30 May
Activity R0-R1,chance R2 R0-R1,chance R2 R0-R1,chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 155/109 155/109 145/99
COMMENT: Solar activity on UT day 27-May was at the R0 level.
The largest region on the solar disk AR3315(S17W03, beta-gamma)
has increased in size and magnetic complexity but has yet to
produce a major flare. Whilst this region has increased in magnetic
complexity, the magnetic gradient currently exhibited in the
intermediate spot area of this sunspot group is not considered
as particularly steep/strong. AR3315 produced 3 minor C class
flares, the largest only a C2.8. However, the region has entered
a solar longitude range where if a major flare does occur it
is more likely to be geoeffective. Other solar regions were either
stable or in slow decay. Solar region AR3314(N12W55, alpha) produced
the largest flare of the day a C8.4 at 27/0435UT. Solar region
AR3311(N18W43, beta) produced two minor C2.9 flares. Solar region
AR3312(S24W35, beta) produced a C6.2 at 27/1924UT. A new small
spot has emerged at N20E05. Small region AR316(N09E27, beta)
is showing some growth. Previously flare active solar region
AR3296 (N15) has not returned to the north east limb. Solar activity
is expected to be at R0-R1, with a chance of an R2 flare (from
AR3315) over 28-30 May. No Earth directed CMEs have been observed.
An eastward non Earth directed CME was observed in LASCO C2 from
27/1224UT associated with an eruptive prominence on the solar
east limb. The solar wind speed on UT day 27-May showed a steady
trend and ranged from 460 to 372 km/s, and is currently near
420 km/s. The peak total interplanetary field strength (IMF,
Bt) was 5nT and the north-south IMF component range was +4 to
-5nT. The solar wind did not decline as much as expected. The
solar wind speed is still expected to continue to decrease to
background level levels as coronal hole effects wane. A small
coronal hole is located just west of the solar meridian at solar
latitude N40, this hole may then produce a very mild increase
in solar wind speed in coming days. Another larger coronal hole
is visible in the southeast solar quadrant. An isolated equatorial
coronal hole is visible in the eastern solar hemisphere. There
is a slight chance for a very weak CME transient signature in
the solar wind parameters on 29-May.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 27 May: G0
Estimated Indices 27 May : A K
Australian Region 1 11000011
Cocos Island 1 12000000
Darwin 1 11100101
Townsville 1 11100011
Learmonth 1 11000011
Alice Springs 1 01100001
Gingin 1 11000011
Canberra 0 01000001
Hobart 1 01000111
Estimated Antarctic Regional K Indices 27 May :
Macquarie Island 0 00000001
Casey 6 23220122
Mawson 19 33211146
Observed Regional daily pc3 Indices 27 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
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 27 May : A
Fredericksburg 3
Planetary 4
Observed AFr/Ap Indices 26 May : A K
Fredericksburg 6
Planetary 6 3211 1122
2B. MAGNETIC FORECAST
Date Ap Conditions
28 May 6 G0
29 May 13 G0, slight chance of G1
30 May 10 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
on UT day 27-May. G0 conditions were mostly observed in the Antarctic
region with an isolated G1 period at Mawson. G0 geomagnetic conditions
are expected over 28-30 May. There is a slight chance for a very
weak glancing blow from a CME on 29-May.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
27 May Normal Fair-normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
28 May Normal Normal Normal
29 May Normal Normal Normal-fair
30 May Normal Normal Normal-fair
COMMENT: HF communication conditions on UT day 27-May were generally
fair to normal, with some mild degradations observed at middle
to high latitudes during local night hours. HF communication
conditions are expected to be mostly normal over 28-30 May. Isolated
shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
27 May 74
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 30% 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
28 May 90 Near predicted monthly values
29 May 90 Near predicted monthly values
30 May 90 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 51 was issued on
25 May and is current for 26-28 May. Maximum usable frequencies
(MUFs) on UT day 27-May were generally slightly depressed to
near predicted monthly values in the Australian region during
the local day, with depressions of up to 30% observed during
local night hours for northern region Australia. Spread-F was
observed at some sites during local night hours. MUFs are expected
to be near predicted monthly values over 28-30 May. Isolated
shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 26 May
Daily Proton Fluence >1 MeV: 3.4E+04
Daily Proton Fluence >10 MeV: 2.3E+04
Daily Electron Fluence >2 MeV: 2.00E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:15%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.4
DSCOVR Satellite Solar Wind Day Averaged Data for 26 May
Speed: 478 km/sec Density: 0.5 p/cc Temp: 140000 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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