[Ips-dsgr] SWS Daily Report - 26 May 21 issued 2330 UT on 26 May 2021
Regional Warning Centre
rwc at ips.gov.au
Thu May 27 09:30:08 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 MAY 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 26 MAY AND FORECAST FOR 27 MAY - 29 MAY
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: ** YELLOW **
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1A. SOLAR SUMMARY
Activity 26 May: Low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 May: 88/32
1B. SOLAR FORECAST
27 May 28 May 29 May
Activity Low Low Low
Fadeouts Possible Possible None expected
10.7cm/SSN 73/9 72/8 72/8
COMMENT: Solar activity was low on UT day 26 May with a series
of C-class and B-class flares mainly from active region AR 2826
(Cso-Beta) and some from AR 2824(Cso-Beta). The only other numbered
region on the visible disk is AR 2825 that has decayed into a
plage. There were no new Earth directed CMEs in the coronagraph
images. Solar activity is expected to be low with a small chance
of M-class flares for the next two UT days 27-28 May and slight
chance of C-class flares on 29 May. On the UT day 26 May, the
solar wind speed was initially at background levels but then
jumped suddenly from 300 km/s up to 350 km/s at 11:37 UT due
to the arrival of a shock from the CME activities observed on
22 and 23 May. The solar wind speed continued increasing up to
400 km/s, with a corresponding jump in density. Before the arrival
of the shock, IMF (Bt) was between 1 and 3 nT and the north-south
component of IMF (Bz) nearly stable between +1/-2 nT. After the
shock, IMF (Bt) peaked at 17 nT and the north-south IMF component
(Bz) range was +/-15 nT. The solar wind speed is expected to
be moderately enhanced on UT day 27 May as CME effects persist
and then slowly decline as CME effects weaken. The solar wind
speed is expected to return to near background levels on UT day
29 May. A weak shock was observed in the solar wind at 1137UT
on 26 May.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 26 May: Quiet to Unsettled
Estimated Indices 26 May : A K
Australian Region 6 01103232
Cocos Island 6 11103232
Darwin 6 11103232
Townsville 6 01103232
Learmonth 4 111030--
Alice Springs 6 01103232
Gingin 5 00003232
Canberra 4 01002232
Hobart 4 01002231
Estimated Antarctic Regional K Indices 26 May :
Macquarie Island 2 00001121
Casey 6 12103132
Mawson 13 42114332
Observed Regional daily pc3 Indices 26 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Melbourne NA
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 26 May : A
Fredericksburg 14
Planetary 19
Observed AFr/Ap Indices 25 May : A K
Fredericksburg 3
Planetary 3 0101 1102
2B. MAGNETIC FORECAST
Date Ap Conditions
27 May 20 Unsettled to active with possible minor storms
28 May 12 Unsettled to Active
29 May 8 Quiet to Unsettled
COMMENT: SWS Geomagnetic Warning 21 was issued on 25 May and
is current for 25-27 May. Geomagnetic conditions in the Australian
were quiet to unsettled on UT day 26 May. In the Antarctic region,
quiet to active levels were observed. On UT day 27 May, unsettled
to active levels are expected with possible minor storms due
to CME effects. Then on UT day 28 May mostly unsettled to active
levels are expected, followed by mostly quiet to unsettled conditions
on UT day 29 May, In the SWS magnetometer data for 26 May, a
weak (10nT) impulse was observed at 1246UT.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 May Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 May Normal Normal-fair Fair
28 May Normal Normal-fair Normal-fair
29 May Normal Normal Normal-fair
COMMENT: Mild to moderate degradation in HF propagation conditions
are possible on UT day 27 May due to the increase in geomagnetic
activity. Mild MUF depressions could occur on UT day 28 May,
followed by mostly normal HF propagation condition son UT day
29 May.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 May 12
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
No data available.
Northern Australian Region:
Depressed 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.
Monthly T index:
Month T index
Apr 12
May 21
Jun 24
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
27 May 0 Depressed 10 to 30%/near predicted monthly values
28 May 10 Near predicted monthly values/depressed 10 to
20%
29 May 15 Near predicted monthly values
COMMENT: SWS HF Communications Warning 17 was issued on 25 May
and is current for 26-27 May. MUFs in the Australian region on
UT day 26 May were mostly near predicted monthly values with
some minor depressions in the Northern Australian region during
the local day. Some mild to moderate MUF depressions are possible
on UT day 27 May due to the increase in geomagnetic activity.
Mild MUF depressions are possible on UT day 28 May, followed
by mostly normal HF propagation conditions on UT day 29 May.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 May
Daily Proton Fluence >1 MeV: 7.0E+04
Daily Proton Fluence >10 MeV: 4.6E+04
Daily Electron Fluence >2 MeV: 7.10E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 9%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: A8.4
DSCOVR Satellite Solar Wind Day Averaged Data for 25 May
Speed: 316 km/sec Density: 7.7 p/cc Temp: 23000 K Bz: -1 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
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Space Weather Services email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386 WWW: http://www.sws.bom.gov.au
Haymarket NSW 1240 AUSTRALIA FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010 fax: +61 2 9213 8060
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