[Ips-dsgr] ASWFC Daily Report - 17 December 23 issued 2330 UT on 17 Dec 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Mon Dec 18 10:30:57 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 DECEMBER 2023
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: R1
Flares Max Fadeout Freq. Sectors
M1.1 2017UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Dec: 155/109
1B. SOLAR FORECAST
18 Dec 19 Dec 20 Dec
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 147/101 145/99 140/94
COMMENT: Solar activity on UT day 17-Dec was at the R1 level,
due to an M1.1 flare at 17/2017UT from AR3514 (N05W92, beta-gamma).
AR3514 has now rotated over the western limb. There are currently
six numbered sunspot regions visible on the solar disk and three
unnumbered regions. AR3519 (S10W14, beta) is the largest region
on the solar disk and has shown decay in its trailer spots. An
unnumbered region is visible near N10E32 (alpha) and has shown
minor growth over the UT day. A second unnumbered region is visible
near N02W42 (beta) and has shown spot growth. A third unnumbered
region was observed near N15E73 (beta) and appears stable. All
other sunspot regions are either stable or in decay. Solar activity
is expected to be at R0-R1 levels over 18-20 Dec. Several CMEs
were observed, but none are considered geoeffective. The solar
wind speed on UT day 17-Dec increased, ranging from 415 to 560
km/s and is currently near 480 km/s. The peak total interplanetary
field strength (IMF, Bt) was 17 nT and the north south IMF component
(Bz) range was +14 to -14 nT. A solar wind shock was observed
at 17/0733UT, indicative of a CME arrival. A period of sustained
southward IMF conditions was observed from 17/0907-1530UT. The
solar wind speed is expected to remain elevated over 18-20 Dec
due to coronal hole high speed wind stream effects from a moderate
sized coronal hole now moving toward a geoeffective position.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Dec: G1
Estimated Indices 17 Dec : A K
Australian Region 25 22535524
Cocos Island 16 12434423
Darwin 20 22534424
Townsville 25 22535524
Learmonth 29 22535535
Alice Springs 28 22535525
Gingin 28 23545524
Canberra 23 13534524
Hobart 26 13535524
Estimated Antarctic Regional K Indices 17 Dec :
Macquarie Island 62 23656833
Casey 30 34654423
Mawson 45 46656432
Observed Regional daily pc3 Indices 17 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 3 (Quiet)
Alice Springs 0 (Quiet)
Gingin 31 (Quiet to unsettled)
Canberra 2 (Quiet)
Hobart 24 (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 17 Dec : A
Fredericksburg 25
Planetary 35
Observed AFr/Ap Indices 16 Dec : A K
Fredericksburg 10
Planetary 11 3421 2133
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Dec 12 G0
19 Dec 12 G0
20 Dec 10 G0
COMMENT: G1 geomagnetic conditions were observed in the Australian
region on UT day 17-Dec due to a CME arrival. Mostly G1-G2 geomagnetic
conditions were observed in the Antarctic region, with an isolated
period of G4 observed at Macquarie Island. G0 geomagnetic conditions
are expected over 18-20 Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Dec Normal-fair Normal-fair Normal
PCA Event : 10MeV Proton/PCA Event Began at 2335UT 15/12, Ended at 0045UT 16/12
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-fair
COMMENT: HF radio communication conditions on UT day 17-Dec were
normal to fair. Mostly normal conditions are expected over 18-20
Dec. Isolated shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Dec 111
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Enhanced by 35% during local night.
Niue Island Region:
Mostly near predicted monthly values.
Depressed by 20% after local dawn.
Northern Australian Region:
Mostly near predicted monthly values.
Depressed by 20% after local dawn.
Southern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values 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
18 Dec 80 Near predicted monthly values/depressed 0 to
15%
19 Dec 90 Near predicted monthly values
20 Dec 100 Near predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 130 was
issued on 15 December and is current for 17-18 Dec. Maximum usable
frequencies (MUFs) were near predicted monthly values in the
Australian region on UT day 17-Dec. Depressions of 20% have been
observed after local dawn in northern Australian regions due
to recent geomagnetic activity. MUFs are generally expected to
be near predicted monthly values over 18-20 Dec. Isolated shortwave
fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Dec
Daily Proton Fluence >1 MeV: 4.5E+07
Daily Proton Fluence >10 MeV: 2.0E+05
Daily Electron Fluence >2 MeV: 2.60E+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 16 Dec
Speed: 471 km/sec Density: 13.2 p/cc Temp: 112000 K Bz: 1 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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