[Ips-dsgr] ASWFC Daily Report - 21 December 23 issued 2330 UT on 21 Dec 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Fri Dec 22 10:30:57 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 DECEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 DECEMBER AND FORECAST FOR 22 DECEMBER - 24 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Dec: R1
Flares Max Fadeout Freq. Sectors
M4.2 0538UT possible lower E. Asia/Aust.
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Dec: 194/146
1B. SOLAR FORECAST
22 Dec 23 Dec 24 Dec
Activity R1 R1 R1
Fadeouts Possible Possible Possible
10.7cm/SSN 194/146 190/143 190/143
COMMENT: Solar activity on UT day 21-Dec was at the R1 level
due to an M4.2 flare at 21/0538UT from AR3519 (S10W68, beta-gamma).
There are currently eight numbered sunspot regions visible on
the solar disk and one unnumbered region. AR3519 has decayed
since producing the R1 level flare. AR3529 (S20E16, beta-gamma)
is the largest region on the solar disk and has shown growth
in its leader spot over the UT day. AR3528 (N09W24, beta) has
shown growth in its trailer spots. AR3526 (N15E19, beta) has
shown some mild spot growth. AR3530 (N09E38, beta) has exhibited
spot development over the 24-hour period. An unnumbered region
is visible near N15E64 (alpha) and appears stable. All other
sunspot regions are either stable or in decay. Solar activity
is expected to be at the R1 level over 22-24 Dec. No Earth-directed
CMEs have been observed. A west directed CME was observed, visible
in STEREO-A coronagraph imagery from 21/0609UT. This CME is likely
associated with the M4.2 flare from AR3519. Modelling indicates
this CME does not contain an Earth-directed component. A filament
extending from N23E28 to N56W15 has remained stable over the
UT day and will continue to be monitored for a potential eruption.
The solar wind speed on UT day 21-Dec decreased, ranging from
340 to 430 km/s and is currently near 345 km/s. The peak total
interplanetary field strength (IMF, Bt) was 5 nT and the north
south IMF component (Bz) range was +3 to -4 nT. The solar wind
is expected to remain near background levels over 22-24 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 Dec: G0
Estimated Indices 21 Dec : A K
Australian Region 2 11121000
Cocos Island 2 20120000
Darwin 2 11220001
Townsville 4 11131111
Learmonth 3 22021000
Alice Springs 1 01020001
Gingin 2 21021000
Canberra 3 11131000
Hobart 4 21131100
Estimated Antarctic Regional K Indices 21 Dec :
Macquarie Island 9 11153100
Casey 12 44421111
Mawson 13 53221223
Observed Regional daily pc3 Indices 21 Dec :
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 21 Dec : A
Fredericksburg 4
Planetary 5
Observed AFr/Ap Indices 20 Dec : A K
Fredericksburg 7
Planetary 9 4312 2211
2B. MAGNETIC FORECAST
Date Ap Conditions
22 Dec 6 G0
23 Dec 8 G0
24 Dec 8 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 21-Dec. G0-G1 geomagnetic conditions were observed
in the Antarctic region. G0 geomagnetic conditions are expected
over 22-24 Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 Dec Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 Dec Normal Normal Normal
23 Dec Normal Normal Normal-fair
24 Dec Normal Normal Normal-fair
COMMENT: HF radio communication conditions on UT day 21-Dec were
mostly normal. Normal conditions are expected over 22-24 Dec.
Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 Dec 129
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Enhanced by 60% during local night.
Niue Island Region:
Near predicted monthly values.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Nov 114
Dec 100
Jan 98
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
22 Dec 130 Near to 15% above predicted monthly values
23 Dec 130 Near to 15% above predicted monthly values
24 Dec 130 Near to 15% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 132 was issued on
21 December and is current for 21-23 Dec. Maximum usable frequencies
(MUFs) on UT day 21-Dec in the Australian region were near predicted
monthly values to 20% enhanced. Sporadic E was observed at several
Australian sites. MUFs are generally expected to be near predicted
monthly values to 15% enhanced over 22-24 Dec. Further sporadic
E can be expected in the Australian region during local night
hours. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 Dec
Daily Proton Fluence >1 MeV: 3.3E+04
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 1.90E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 20 Dec
Speed: 486 km/sec Density: 1.5 p/cc Temp: 144000 K Bz: -2 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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