[Ips-dsgr] ASWFC Daily Report - 17 December 24 issued 2330 UT on 17 Dec 2024 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Dec 18 10:30:56 AEDT 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 DECEMBER 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 DECEMBER AND FORECAST FOR 18 DECEMBER - 20 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Dec: 170/124
1B. SOLAR FORECAST
18 Dec 19 Dec 20 Dec
Activity R0-R1, chance R2 R0-R1, chance R2 R0-R1, chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 170/124 175/129 190/143
COMMENT: Solar activity on UT day 17-Dec was at the R0 level,
with only low level C-class flares observed. There are currently
five numbered sunspot regions visible on the solar disk and one
unnumbered region. AR3922 (S19W20, beta) continued to show spot
development over the UT day. AR3924 (S20W49, beta-delta) is the
most magnetically complex region on the solar disk. An unnumbered
region is visible at around S05E45 with beta magnetic complexity.
All other sunspot regions appeared stable. Solar activity is
expected to be at R0-R1 levels with a chance of R2 over 18-20
Dec. S0 solar radiation storm conditions were observed on UT
day 17-Dec, with a slight enhancement in >10MeV protons observed.
S0 solar radiation storm conditions are expected over 18-20 Dec.
Several CMEs were observed on 17-Dec, but none are considered
geoeffective. A fast, partial halo CME is visible from 17/1612UT
in SOHO imagery. Associated coronal movement behind the southern
limb is visible from 17/1611UT in GOES SUVI imagery. This CME
is considered a far side event. A strong shock in the solar wind
was detected at 17/0442UT due to an impact from a CME first observed
on 15-Dec. The solar wind speed was at background levels until
the shock was observed after which the wind speed increased and
remained elevated over the UT day. The wind speed ranged between
380 km/s and 700 km/s and is currently at around 500 km/s. A
sudden shock in the IMF conditions was also observed from 17/0442UT
due to the CME impact. The peak total interplanetary field strength
(IMF, Bt) was 32 nT and the north-south IMF range (Bz) was +28
to -21 nT. Bz was mostly negative (southward) for the first half
of the UT day before switching to mostly positive (northward)
from around 17/0720UT. The solar wind speed is expected to remain
elevated on 18-Dec, with a decline possible in the second half
of the UT day. A decline towards background levels is expected
over 19-20 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Dec: G1
Estimated Indices 17 Dec : A K
Australian Region 34 25555533
Cocos Island 24 24544522
Darwin 33 25555523
Townsville 41 35555634
Learmonth 39 35555633
Alice Springs 34 25555533
Gingin 35 35555533
Canberra 39 35655533
Kennaook Cape Grim 38 25655533
Hobart 36 25654533
Estimated Antarctic Regional K Indices 17 Dec :
Macquarie Island 24 25543432
Casey 69 47863334
Mawson 51 57653335
Observed Regional daily pc3 Indices 17 Dec :
Darwin 2 (Quiet)
Townsville 6 (Quiet)
Learmonth 20 (Quiet)
Alice Springs 6 (Quiet)
Gingin 51 (Unsettled)
Canberra 55 (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 17 Dec : A
Fredericksburg 23
Planetary 31
Observed AFr/Ap Indices 16 Dec : A K
Fredericksburg 11
Planetary 14 1233 3343
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Dec 10 G0, chance G1
19 Dec 8 G0
20 Dec 5 G0
COMMENT: Mostly G1 geomagnetic conditions were observed in the
Australian region on UT day 16-Dec, with periods of G2 conditions
observed at Townsville, Learmonth, Canberra, Kennaook Cape Grim
and Hobart. G3-G4 conditions were observed in the Antarctic region,
with G1 conditions observed at Macquarie Island. G0 geomagnetic
conditions, with a chance of G1 are expected on 18-Dec due to
ongoing CME impact effects. G0 conditions are expected on 19-20
Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Dec Fair-normal Fair-normal Fair-poor
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Dec Normal Normal Normal-fair
19 Dec Normal Normal Normal-fair
20 Dec Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 17-Dec were
mostly fair with poorer conditions at the start and end of the
UT day and at high latitudes. HF radio propagation conditions
are expected to be fair to normal over 18-Dec due to geomagnetic
activity. Conditions are expected to be recovering towards normal
on 19-20 Dec. Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Dec 121
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 20% during local day.
Near predicted monthly values during local night.
Niue Island Region:
Enhanced by 25% during local day.
Near predicted monthly values during local night.
Depressed by 25% after local dawn.
Northern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Depressed by 25% after local dawn.
Southern Australian Region:
Mostly near predicted monthly values.
Depressed by 40% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 20% over the UT day.
Monthly T index:
Month T index
Nov 127
Dec 117
Jan 114
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
18 Dec 120 Near predicted monthly values
19 Dec 130 Near predicted monthly values
20 Dec 130 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the northern Australian
region on UT day 17-Dec were mostly near predicted monthly values
to 15% enhanced. MUFs in the southern Australian region were
near predicted monthly values to depressed by 40% during local
dawn. Sporadic E was observed at multiple locations in the Australian
region during local night. MUFs are expected to be near predicted
monthly vales over 18-20 Dec, with mild depressions possible
on 18-Dec due to possible ongoing geomagnetic activity. Sporadic
E is more likely to be observed around the Australian region
over December than at other times of the year. Shortwave fadeouts
are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Dec
Daily Proton Fluence >1 MeV: 2.1E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.30E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.3
DSCOVR Satellite Solar Wind Day Averaged Data for 16 Dec
Speed: 396 km/sec Density: 6.8 p/cc Temp: 89000 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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