[Ips-dsgr] SWS Daily Report - 18 April 21 issued 2330 UT on 18 Apr 2021
Regional Warning Centre
rwc at ips.gov.au
Mon Apr 19 09:30:07 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 APRIL 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 18 APRIL AND FORECAST FOR 19 APRIL - 21 APRIL
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
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1A. SOLAR SUMMARY
Activity 18 Apr: Very low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Apr: 78/17
1B. SOLAR FORECAST
19 Apr 20 Apr 21 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 75/13 75/13
COMMENT: Solar activity was very low on UT day 18 April. There
are currently three numbered regions on the visible disk, AR
2814, AR 2815, and AR 2816. Solar activity is expected to be
very low to low for the next three UT days, 19-21 April. The
CME first observed in LASCO C2 imagery near 18/0700 UT is a limbside
event. Based on the location of the CME source, it is unlikely
to impact the Earth. On 18 April, the solar wind speed has decreased
from 590 km/s to 540-560 km/s in response to the waning effects
of the Southern polar coronal hole with extension into the low
latitudes. The IMF (Bt) range was 2-6 nT and north-south IMF
(Bz) range was +5/-6 nT. The IMF Bz was mostly southward since
18/0320 UT. The solar wind speed is expected to remain elevated
on 19-20 April due to the coronal hole effects.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Apr: Quiet to Active
Estimated Indices 18 Apr : A K
Australian Region 15 33343233
Cocos Island 10 33233122
Darwin 11 33332123
Townsville 15 33343233
Learmonth 15 33343233
Alice Springs 14 33343223
Gingin 16 33343333
Canberra 14 32343233
Hobart 17 33353232
Estimated Antarctic Regional K Indices 18 Apr :
Macquarie Island 35 33575222
Casey 35 35333565
Mawson 66 75553376
Observed Regional daily pc3 Indices 18 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 4 (Quiet)
Alice Springs 2 (Quiet)
Gingin 78 (Active)
Canberra 73 (Active)
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 18 Apr : A
Fredericksburg 11
Planetary 14
Observed AFr/Ap Indices 17 Apr : A K
Fredericksburg 20
Planetary 24 4454 3334
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Apr 13 Quiet to Active
20 Apr 8 Quiet to Unsettled
21 Apr 7 Quiet
COMMENT: Mostly quiet to active geomagnetic conditions were observed
in the Australian region on UT day 18 April. Quiet to storm levels
were observed in the Antarctic region. The observed elevated
geomagnetic activity is due to the coronal hole effects. On 19-20
April, geomagnetic activity is expected to be mostly at quiet
to unsettled levels with possible isolated active periods on
19 April due to coronal hole effects. Mostly quiet conditions
are expected for UT day 21 April.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Apr Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Apr Normal Normal Normal-fair
20 Apr Normal Normal Normal-fair
21 Apr Normal Normal Normal-fair
COMMENT: Mostly normal HF propagation conditions are expected.
Moderately degraded conditions may be observed on 19 April at
high latitudes.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Apr 24
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
No data available.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
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
19 Apr 10 Near predicted monthly values/depressed 10 to
25%
20 Apr 10 Near predicted monthly values
21 Apr 10 Near predicted monthly values
COMMENT: MUFs over the Australian regions were mostly near predicted
monthly levels on UT day 18 April. Mild enhancements were observed
in the Southern Australian region during local night. Mild to
moderate MUFs depressions are possible on 19 April due to the
recent increase in geomagnetic activity.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Apr
Daily Proton Fluence >1 MeV: 2.5E+05
Daily Proton Fluence >10 MeV: 4.2E+04
Daily Electron Fluence >2 MeV: 3.00E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: A4.4
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Apr
Speed: 574 km/sec Density: 12.2 p/cc Temp: 354000 K Bz: -2 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
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