[Ips-dsgr] ASWFC Daily Report - 18 April 23 issued 2330 UT on 18 Apr 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Wed Apr 19 09:30:55 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 APRIL AND FORECAST FOR 19 APRIL - 21 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 18 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Apr: 153/108
1B. SOLAR FORECAST
19 Apr 20 Apr 21 Apr
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 150/105 145/99 140/94
COMMENT: Solar activity on UT day 18-Apr was at the R0 level,
with several low level C-class flares. There are currently eight
numbered sunspot regions visible on the solar disk. AR3282 (N11E01,
beta-gamma) is the largest and most magnetically complex region
on the solar disk and has shown some minor spot development in
its intermediate spots. AR3284 (S09E54, beta) has shown some
growth in its leading spot. AR3272 (S21W87, alpha) will soon
rotate over the eastern limb and appears to be decaying. All
other sunspot regions are either stable or in decay. Solar activity
is expected to be at R0-R1 levels over 19-21 Apr. No Earth-directed
CMEs have been observed. The solar wind speed on UT day 18-Apr
increased, ranging from 405 to 615 km/s, and is currently near
595 km/s. A minor shock indicative of a CME impact was observed
in the solar wind at 18/1319UT. The peak total interplanetary
field strength (IMF, Bt) was 20 nT and the north-south IMF component
(Bz) range was +18 to -17 nT. A short period of sustained southward
IMF conditions was observed from 18/1547UT to 18/1630UT. The
solar wind speed is expected to remain elevated over 19-21 Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Apr: G1
Estimated Indices 18 Apr : A K
Australian Region 8 12103332
Cocos Island 7 11103332
Darwin 9 12103432
Townsville 12 12104433
Learmonth 13 12105432
Alice Springs 7 02103332
Gingin 7 11103332
Canberra 6 01003332
Hobart 7 12103322
Estimated Antarctic Regional K Indices 18 Apr :
Macquarie Island 2 01001221
Casey 12 24312242
Mawson 15 12104444
Observed Regional daily pc3 Indices 18 Apr :
Darwin 0 (Quiet)
Townsville 2 (Quiet)
Learmonth 2 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 15 (Quiet)
Hobart 34 (Quiet to unsettled)
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 12
Planetary 18
Observed AFr/Ap Indices 17 Apr : A K
Fredericksburg 6
Planetary 5 1111 1222
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Apr 16 G0, chance G1
20 Apr 20 G0, chance G1
21 Apr 16 G0, chance G1
COMMENT: ASWFC Geomagnetic Warning 18 was issued on 17 April
and is current for 19-21 Apr. G1 geomagnetic conditions were
observed in the Australian region on 18-Apr, with one period
of G1 observed at Learmonth following a weak impulse detected
at 18/1400UT, indicative of a CME arrival. G0 geomagnetic conditions
were observed in the Antarctic region. G0 geomagnetic conditions
are expected over 19-21 Apr, with a chance of G1 due to weak
glancing blow(s) from recent CME activity.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Apr Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Apr Normal Normal-fair Fair
20 Apr Normal Normal Normal-fair
21 Apr Normal Normal Normal-fair
COMMENT: Normal HF propagation conditions were observed on 18-Apr.
Mostly normal HF propagation conditions are expected over 19-21
Apr. Mild degradations are possible for middle to high latitudes
on 19-Apr. Isolated shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Apr 117
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 25% during local day.
Enhanced by 45% during local night.
Niue Island Region:
Enhanced by 20% during local day.
Enhanced by 30% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Southern Australian Region:
Enhanced by 20% during local day.
Enhanced by 15-20% during local night and after local dawn.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Enhanced by 30% over the UT day.
Monthly T index:
Month T index
Mar 132
Apr 84
May 84
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
19 Apr 120 15-20% above predicted monthly values
20 Apr 120 15-20% above predicted monthly values
21 Apr 120 15-20% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 37 was issued on
16 April and is current for 17-19 Apr. Maximum usable frequencies
(MUFs) on UT day 18-Apr in the Australian region were enhanced
by 15-25%. Spread F was observed during local night hours at
Hobart. MUFs are expected to be 15-20% enhanced over 19-21 Apr.
Isolated shortwave fadeouts are possible. Mildly degraded conditions
are possible during local night hours on 19-Apr for southern
Australian regions due to possible arrival of a weak CME component.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Apr
Daily Proton Fluence >1 MeV: 3.8E+04
Daily Proton Fluence >10 MeV: 2.3E+04
Daily Electron Fluence >2 MeV: 1.40E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Apr
Speed: 366 km/sec Density: 3.5 p/cc Temp: 114000 K Bz: 4 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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