[Ips-dsgr] ASWFC Daily Report - 14 December 25 issued 2330 UT on 14 Dec 2025 [SEC=OFFICIAL]

Australian Space Weather Forecasting Centre aswfc at bom.gov.au
Mon Dec 15 10:30:53 AEDT 2025


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/14 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 14 DECEMBER AND FORECAST FOR 15 DECEMBER - 17 DECEMBER
STATUS INDICATORS SOL:GREEN   MAG:GREEN     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 14 Dec:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 14 Dec: 119/71


1B. SOLAR FORECAST
             15 Dec             16 Dec             17 Dec
Activity     R0                 R0                 R0
Fadeouts     None expected      None expected      None expected
10.7cm/SSN   120/72             120/72             120/72

COMMENT: Solar activity was at the R0 level for UT day 14-Dec. 
There is currently no solar region of significant area on the 
visible solar disk. Solar region AR4296 located behind the southwest 
solar limb at solar latitude S16 produced a C3.8 flare at 14/0742UT. 
Solar region AR4304 (N25W85, beta) and AR4307 (S15W31, beta-gamma) 
produced low level C class flares. Solar region AR4308 (N17E33, 
beta) continues to grow though remained flare quiet. The chance 
of an isolated R1 flare may be slightly increasing if AR4308 
and AR4307 continue to develop in coming days. Region AR4304 
is rotating off disk. There are currently five regions on the 
visible solar disk. Other regions are stable or in decay. R0 
conditions are forecast for 15-17 Dec. S0 solar radiation storm 
conditions were observed on 14-Dec. S0 solar radiation storm 
conditions are expected over 15-17 Dec. The longer transequatorial 
eastern arm of a north polar extension coronal hole is now at 
the solar central meridian. No geoeffective coronal mass ejections 
were observed over the past UT day. A southwest CME, with limited 
expansion, was observed from 14/0800UT in association with the 
C3.8 flare from behind the southwest solar limb. This event is 
not considered to be Earth directed. The solar wind speed decreased 
over the UT day as the influence from the western arm of the 
coronal hole currently visible on the solar disk declines. The 
solar wind speed ranged between 667-490 km/s and is currently 
at 487 km/s. The peak total interplanetary magnetic field strength 
(IMF, Bt) was 5 nT and the north-south IMF component (Bz) range 
was -3 to 4 nT. The interplanetary magnetic field strength is 
currently very small in magnitude. The solar wind speed is expected 
to continue to decline over the next few days before increasing 
again on 18-Dec due to the wind stream from the transequatorial 
eastern arm of the coronal hole now at the solar central meridian.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 14 Dec: G0

Estimated Indices 14 Dec : A   K           
   Australian Region       4   12121121
      Cocos Island         3   12111110
      Darwin               4   11121221
      Townsville           5   22121121
      Learmonth            5   12121222
      Alice Springs        4   11121211
      Gingin               6   22121222
      Canberra             3   12111111
      Kennaook Cape Grim   4   12211121
      Hobart               4   12211111    

Estimated Antarctic Regional K Indices 14 Dec :
      Macquarie Island     3   11112111
      Casey               25   46532232
      Mawson              20   54333242

Observed Regional daily pc3 Indices 14 Dec : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               8   (Quiet)
      Canberra             2   (Quiet)
      Hobart              29   (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 14 Dec : A 
           Fredericksburg         7
           Planetary              8                         

Observed AFr/Ap Indices 13 Dec :  A   K
           Fredericksburg         8
           Planetary             14   5222 3233     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
15 Dec     8    G0
16 Dec     6    G0
17 Dec    14    G0, chance of G1 toward end of the UT day

COMMENT: G0 geomagnetic conditions were observed in the Australian 
region on UT day 14-Dec. In the Antarctic region isolated periods 
of G1-G2 conditions were observed at Mawson and Casey and G0 
conditions were observed at Macquarie Island. G0 conditions are 
generally expected over 15-17 Dec. The Earth is expected to enter 
a coronal hole wind stream on 18-Dec, there may be an increase 
in geomagnetic activity late in the UT day on 17-Dec.

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

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
15 Dec      Normal         Normal         Normal-fair
16 Dec      Normal         Normal         Normal
17 Dec      Normal         Normal         Normal-fair

COMMENT: HF radio propagation conditions on UT day 14-Dec were 
generally fair to normal, with poor to fair conditions at times 
at high latitudes. HF conditions are expected to be normal for 
15-17 Dec.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
14 Dec    73

Observed Australian Regional MUFs
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Depressed by 15% during local day.
      Near predicted monthly values.
   Southern Australian Region:
      Depressed 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      103
Dec      89
Jan      89

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
15 Dec   100    Near predicted monthly values
16 Dec   100    Near predicted monthly values
17 Dec   100    Near predicted monthly values

COMMENT: Maximum usable frequencies (MUFs) in the Australian 
region on UT day 14-Dec were 15% depressed to near predicted 
monthly values, with depressed conditions observed during the 
local day. MUFs are expected to be near predicted monthly values 
for 15-17 Dec.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 13 Dec
       Daily Proton Fluence >1 MeV:   4.5E+05
       Daily Proton Fluence >10 MeV:  1.4E+04
       Daily Electron Fluence >2 MeV: 1.30E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B7.3

DSCOVR Satellite Solar Wind Day Averaged Data for 13 Dec
Speed: 561 km/sec  Density:    2.7 p/cc  Temp:   264000 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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