[Ips-dsgr] ASWFC Daily Report - 16 December 24 issued 2330 UT on 16 Dec 2024 [SEC=OFFICIAL]

Australian Space Weather Forecasting Centre aswfc at bom.gov.au
Tue Dec 17 10:30:43 AEDT 2024


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/16 DECEMBER 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 16 DECEMBER AND FORECAST FOR 17 DECEMBER - 19 DECEMBER
STATUS INDICATORS SOL:** YELLOW **   MAG:** RED **     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 16 Dec:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 16 Dec: 167/121


1B. SOLAR FORECAST
             17 Dec             18 Dec             19 Dec
Activity     R0-R1, chance R2   R0-R1, chance R2   R0-R1, chance R2
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   170/124            170/124            175/129

COMMENT: Solar activity on UT day 16-Dec was at the R0 level, 
with only low level C-class flares observed. There are currently 
six numbered sunspot regions visible on the solar disk. AR3922 
(S19W10, beta) and AR3924 (S19W40, beta) both showed spot development 
over the UT day. All other sunspots appeared stable. Solar activity 
is expected to be at R0-R1 levels with a chance of R2 over 17-19 
Dec. S0 solar radiation storm conditions were observed on UT 
day 16-Dec, with a very slight enhancement in >10MeV protons 
observed. S0 solar radiation storm conditions are expected over 
17-19 Dec. No geoeffective CMEs were observed on 16-Dec. A partial 
halo CME from 15-Dec has been further analysed. This CME is obscured 
by a denser non-geoeffective CME in SOHO imagery, making analysis 
more complicated. Modelling of this CME suggests a component 
will impact Earth on 17-Dec at 1000UT +/- 12 hours. An energetic 
ion enhancement event began at 16/1850UT which may be a precursor 
of this CME impact. The solar wind speed decreased on UT day 
16-Dec. The solar wind speed ranged between 350 km/s and 470 
km/s and is currently near 380 km/s. A mild spike in the solar 
wind speed was observed at around 16/0335UT but did not change 
the overall downward trajectory over the UT day. This spike was 
concurrent with a spike in solar wind density and is likely indictive 
of a mild CME impact. The peak total interplanetary field strength 
(IMF, Bt) was 12 nT and the north-south IMF range (Bz) was +6 
to -7 nT. The solar wind speed is expected to increase on 17-Dec 
due to an impact from a CME first observed on 15-Dec. The solar 
wind speed is expected to be elevated with a declining trend 
over 18-19 Dec.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 16 Dec: G0

Estimated Indices 16 Dec : A   K           
   Australian Region       8   13221232
      Cocos Island         7   13221222
      Darwin               8   23221232
      Townsville          12   24221333
      Learmonth           10   14221332
      Alice Springs        8   13221232
      Gingin               8   23221232
      Canberra             9   13221233
      Kennaook Cape Grim  12   13332333
      Hobart              12   13332333    

Estimated Antarctic Regional K Indices 16 Dec :
      Macquarie Island    19   03454332
      Casey               24   46342233
      Mawson              20   35433333

Observed Regional daily pc3 Indices 16 Dec : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             4   (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 16 Dec : A 
           Fredericksburg        11
           Planetary             12                         

Observed AFr/Ap Indices 15 Dec :  A   K
           Fredericksburg         9
           Planetary             10   2313 3232     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
17 Dec    25    G1, chance of G2
18 Dec    10    G0
19 Dec     8    G0

COMMENT: G0 geomagnetic conditions were observed in the Australian 
region on UT day 16-Dec. Mostly G1 conditions were observed in 
the Antarctic region, with a period of G2 observed at Casey. 
G1 geomagnetic conditions, with a chance of G2 are expected on 
17-Dec due to an anticipated impact from a CME first observed 
on 15-Dec. G0 conditions are expected on 18-19 Dec.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
16 Dec      Fair-normal    Fair           Poor-fair      

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
17 Dec      Fair           Fair           Fair-poor
18 Dec      Normal-fair    Normal-fair    Fair-normal
19 Dec      Normal         Normal         Normal-fair

COMMENT: HF radio propagation conditions on UT day 16-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 17-18 Dec due to anticipated 
geomagnetic activity. Conditions are expected to be mostly normal 
on 19-Dec. Shortwave fadeouts are possible.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
16 Dec   115

Observed Australian Regional MUFs
   Cocos Island Region:
      Enhanced by 25% during local day.
      Enhanced by 15% during local night.
   Niue Island Region:
      Enhanced by 15% during local day.
      Depressed by 15% during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values 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
17 Dec   120    Near predicted monthly values
18 Dec   120    Near predicted monthly values
19 Dec   130    Near predicted monthly values

COMMENT: ASWFC SWF HF Communications Warning 144 was issued on 
15 December and is current for 15-17 Dec. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 16-Dec were mostly 
near predicted monthly values. Sporadic E was observed at Perth 
and Townsville during local night. Spread F was observed at Hobart 
during local night. MUFs are expected to be near predicted monthly 
vales over 17-19 Dec, with mild depressions possible on 17-18 
Dec due to anticipated 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 15 Dec
       Daily Proton Fluence >1 MeV:   9.4E+05
       Daily Proton Fluence >10 MeV:  1.4E+04
       Daily Electron Fluence >2 MeV: 1.20E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: C1.4

DSCOVR Satellite Solar Wind Day Averaged Data for 15 Dec
Speed: 408 km/sec  Density:    5.9 p/cc  Temp:    58700 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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