[Ips-dsgr] SWS Daily Report - 27 April 21 issued 2330 UT on 27 Apr 2021
Regional Warning Centre
rwc at ips.gov.au
Wed Apr 28 09:30:09 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/27 APRIL 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 27 APRIL AND FORECAST FOR 28 APRIL - 30 APRIL
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN
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1A. SOLAR SUMMARY
Activity 27 Apr: Very low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 27 Apr: 79/19
1B. SOLAR FORECAST
28 Apr 29 Apr 30 Apr
Activity Very low to low Very low to low Very low to low
Fadeouts None expected None expected None expected
10.7cm/SSN 78/17 78/17 78/17
COMMENT: Solar activity was very low on UT day 27 April with
just a few B-class flares from region 2821. There are currently
three spotted regions on the visible disk, ARs 2818, 2820, and
2821. A Disappearing Solar Filament was observed in the SDO images
near S50W05 at about 26/19 UT that may be associated with a CME
observed in Lasco and Stereo-A images at 26/21 UT. Further analysis
is required to confirm that this CME has an Earth directed component.
No other Earth directed CMEs were observed in the available coronagraph
images. Solar activity is expected to be very low for the next
three UT days, 28-30 April with a chance of a C-class flare.
On UT day 27 April, the solar wind speed remained enhanced, varying
mostly between 430 km/s and 500 km/s, because of persistent coronal
hole and CME effects. The IMF (Bt) peaked at 5 nT and the north-south
IMF (Bz) range was +2/-4 nT. The IMF Bz component sustained mainly
southward orientation during 27/0000-1340 UT and was mostly negative
after 27/1630 UT. The enhanced solar wind speed is expected to
start decreasing back to nominal levels on UT days 28-29 April.
However on UT day 30 April the combined effect of another equatorial
coronal hole moving into geoeffective position, plus the 26/21
UT CME could elevate the solar wind speed from slightly enhanced
to moderately enhanced levels.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 27 Apr: Quiet
Estimated Indices 27 Apr : A K
Australian Region 4 22222100
Cocos Island 2 11111100
Darwin 6 22221---
Townsville 5 22222111
Learmonth 5 22222200
Alice Springs 4 22221100
Gingin 5 12222210
Canberra 5 22232100
Hobart 5 22232100
Estimated Antarctic Regional K Indices 27 Apr :
Macquarie Island 8 22342200
Casey 8 33222211
Mawson 22 55332234
Observed Regional daily pc3 Indices 27 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 2 (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 27 Apr : A
Fredericksburg 8
Planetary 9
Observed AFr/Ap Indices 26 Apr : A K
Fredericksburg 12
Planetary 14 4431 3222
2B. MAGNETIC FORECAST
Date Ap Conditions
28 Apr 8 Quiet to Unsettled
29 Apr 7 Quiet
30 Apr 18 Unsettled to active with the chance of a minor
storm
COMMENT: Geomagnetic conditions in the Australian region were
mostly at quiet levels on UT day 27 April. Quiet to active levels
with a minor storm period were observed in the Antarctic region.
Mostly quiet to unsettled conditions are expected on UT day 28
April due to waning coronal hole and CME effects. Then mostly
quiet conditions are expected on UT day 29 April. However the
combined effect of an equatorial coronal hole and the CME from
a Disappearing Solar Filament on 26 April at 19 UT, if it impacts
Earth, could cause unsettled to active conditions on UT day 30
April with the chance of a minor storm.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
27 Apr Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
28 Apr Normal Normal Normal-fair
29 Apr Normal Normal Normal
30 Apr Normal Normal-fair Fair
COMMENT: Mostly normal HF propagation conditions are expected
on UT days 28-29 April.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
27 Apr 22
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Enhanced by 30% during local day.
No data available 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
Mar 9
Apr 19
May 23
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
28 Apr 20 Near predicted monthly values
29 Apr 20 Near predicted monthly values
30 Apr 20 Near predicted monthly values
COMMENT: MUFs in the Australian region on UT day 27 April were
mostly near predicted monthly values. MUFs are expected to be
mostly near predicted monthly values on UT days 28-30 April.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 26 Apr
Daily Proton Fluence >1 MeV: 8.9E+04
Daily Proton Fluence >10 MeV: 4.3E+04
Daily Electron Fluence >2 MeV: 2.90E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: A7.1
DSCOVR Satellite Solar Wind Day Averaged Data for 26 Apr
Speed: 484 km/sec Density: 4.8 p/cc Temp: 176000 K Bz: 0 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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