[Ips-dsgr] SWS Daily Report - 20 December 21 issued 2344 UT on 20 Dec 2021
rwc
rwc at ips.gov.au
Tue Dec 21 10:44:36 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 DECEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 20 DECEMBER AND FORECAST FOR 21 DECEMBER - 23 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
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1A. SOLAR SUMMARY
Activity 20 Dec: Moderate
Flares Max Fadeout Freq. Sectors
M1.8 1139UT possible lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Dec: 123/76
1B. SOLAR FORECAST
21 Dec 22 Dec 23 Dec
Activity Low to moderate Low to moderate Low to moderate
Fadeouts Possible Possible Possible
10.7cm/SSN 124/77 122/75 120/72
COMMENT: Solar activity was Moderate for 20Dec with the largest
event being the M1.8 flare from region 2908 (S20W10) at 1136UT.
A partial halo CME was associated with this event and initial
ENLIL analysis of this flare estimates arrival period late in
UT day 23Dec through to midway in the UT day 24Dec. Further analysis
of this event is currently in progress. Additional C-class activity
was observed from region 2907 which appears to be the most complex
region on the visible disk. There are currently 7 numbered regions
on the visible solar disk with most appear to be stable or showing
signs of decay. The north-south component of the IMF (Bz) began
the day ranging between +13nT and -10nT between 00UT-02UT. This
was due to a CIR ahead of the high speed solar wind stream from
the small southern hemisphere located negative polarity coronal
hole. Bz then reduced in magnitude for the remainder of the UT
day, ranging between +/-7nT. The solar wind speed was 435km/s
at 00UT and then increased to ~530km/s from 01UT onwards. Solar
wind velocity has remained elevated, peaking at 631km/s at 1826UT
and is currently 606km/s at the time of this report. Solar wind
speed is expected to remain elevated over the next 2 days due
to a larger negative polarity equatorial located coronal hole
effects that are expected to influence the solar wind. Solar
activity is expected to be Low to Moderate over the next 3 days.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 Dec: Quiet to Active
Estimated Indices 20 Dec : A K
Australian Region 12 42232323
Cocos Island 6 32122211
Darwin 10 42222322
Townsville 13 42233323
Learmonth 16 52233323
Alice Springs 10 32222323
Gingin 15 52232323
Canberra 11 33322223
Hobart 13 43332223
Estimated Antarctic Regional K Indices 20 Dec :
Macquarie Island 25 33464422
Casey 36 65643333
Mawson 28 44434445
Observed Regional daily pc3 Indices 20 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 8 (Quiet)
Canberra 23 (Quiet to unsettled)
Hobart 21 (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 20 Dec : A
Fredericksburg 13
Planetary 17
Observed AFr/Ap Indices 19 Dec : A K
Fredericksburg 8
Planetary 12 0000 2444
2B. MAGNETIC FORECAST
Date Ap Conditions
21 Dec 20 Active
22 Dec 14 Unsettled to Active
23 Dec 10 Quiet to Unsettled
COMMENT: SWS Geomagnetic Warning 42 was issued on 20 December
and is current for 20-22 Dec. Quiet to Active geomagnetic conditions
for the Australian region observed on 20Dec with Minor Storm
conditions for Antarctic regions due to a CIR ahead of a high
speed solar wind stream from a small southern hemisphere located
coronal hole. Geomagnetic conditions are expected to be Quiet
to Active with possible isolated Minor Storm periods for 21Dec
and Unsettled to Active conditions expected for 22Dec-23Dec due
to the effects of a larger equatorial located negative polarity
coronal hole. On 23Dec there is also the chance late in the UT
day of the arrival of a glancing blow CME from the M-class flare
today. In the SWS magnetometer data for 20 Dec, a weak (9nT)
impulse was observed at 1434UT.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 Dec Normal Normal-fair Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 Dec Normal Normal-fair Fair
22 Dec Normal Normal Normal-fair
23 Dec Normal Normal Normal-fair
COMMENT: Mostly Normal HF conditions observed for 20Dec across
Low latitudes with some observed depressed periods for Mid to
High latitudes. HF conditions expected to range from near predicted
monthly values to depressed over the next 3 days due to increased
geomagnetic activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 Dec 33
Observed Australian Regional MUFs
Cocos Island Region:
Mostly near predicted monthly values.
Enhanced by 25% after local dawn.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Depressed by 25% during local day.
Near predicted monthly values during local night.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Nov 3
Dec 33
Jan 36
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
21 Dec 30 Near predicted monthly values/depressed 10 to
30%
22 Dec 20 Near predicted monthly values/depressed 10 to
30%
23 Dec 25 Near predicted monthly values/depressed 10 to
30%
COMMENT: SWS HF Communications Warning 41 was issued on 20 December
and is current for 20-22 Dec. MUFs in the Australian region for
20Dec ranged from near predicted monthly values to slightly enhanced
by 15-30% for Equatorial and Northern AUS regions. Notable depressed
periods for Southern AUS/NZ regions and disturbed ionospheric
support for Antarctic regions. MUFs are expected to be mostly
near predicted monthly values for Equatorial and Northern AUS
regions with anticipated depressions of 10%-30% for Southern
AUS/NZ regions and disturbed conditions for Antarctic regions
for the next 3 due to expected increase in geomagnetic activity
over this period. Chance of short-wave fadeouts 21Dec-22Dec.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 Dec
Daily Proton Fluence >1 MeV: 3.0E+06
Daily Proton Fluence >10 MeV: 4.5E+04
Daily Electron Fluence >2 MeV: 5.10E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B4.0
DSCOVR Satellite Solar Wind Day Averaged Data for 19 Dec
Speed: 351 km/sec Density: 10.0 p/cc Temp: 51300 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
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