[Ips-dsgr] ASWFC Daily Report - 25 December 23 issued 2331 UT on 25 Dec 2023 [SEC=OFFICIAL]

Regional Warning Centre rwc at ips.gov.au
Tue Dec 26 10:31:00 EST 2023


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 DECEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 25 DECEMBER AND FORECAST FOR 26 DECEMBER - 28 DECEMBER
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 25 Dec:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Dec: 167/121


1B. SOLAR FORECAST
             26 Dec             27 Dec             28 Dec
Activity     R0-R1              R0-R1              R0-R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   170/124            165/119            160/114

COMMENT: Solar activity on UT day 25-Dec was at the R0 level, 
with several low level C-class flares. There are currently seven 
numbered sunspot regions visible on the solar disk and one unnumbered 
region. AR3529 (S20W38, beta) is the largest region on the solar 
disk, but has remained flare quiet and shown slight decay in 
its leader spots. AR3528 (N09W78, beta) appears stable and will 
soon rotate over the western limb. AR3531 (S20E03, beta) has 
exhibited spot development over the UT day. An unnumbered region 
is visible near S01E26 (beta) and has shown spot growth. All 
other sunspot regions are either stable or in decay. Solar activity 
is expected to be at R0-R1 levels over 26-28 Dec. No Earth-directed 
CMEs have been observed. A northwest directed CME was observed, 
visible in LASCO C2 and STEREO-A coronagraph imagery from 25/1323UT. 
This CME is associated with a limb prominence eruption and is 
not considered geoeffective. The solar wind speed on UT day 25-Dec 
increased, ranging from 355 to 450 km/s and is currently near 
430 km/s. The peak total interplanetary field strength (IMF, 
Bt) was 7 nT and the north south IMF component (Bz) range was 
+6 to -5 nT. The solar wind is expected to increase over 26-28 
Dec due to expected CME arrivals.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 25 Dec: G0

Estimated Indices 25 Dec : A   K           
   Australian Region       3   21100122
      Cocos Island         1   11100110
      Darwin               3   21100112
      Townsville           4   21200122
      Learmonth            3   21200112
      Alice Springs        2   11100112
      Gingin               3   21100122
      Canberra             2   11100121
      Hobart               3   11200121    

Estimated Antarctic Regional K Indices 25 Dec :
      Macquarie Island     1   11000011
      Casey               22   45542123
      Mawson              10   33212332

Observed Regional daily pc3 Indices 25 Dec : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             0   (Quiet)
      Hobart               0   (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 25 Dec : A 
           Fredericksburg         4
           Planetary              4                         

Observed AFr/Ap Indices 24 Dec :  A   K
           Fredericksburg         7
           Planetary              7   2323 2101     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
26 Dec     5    G0
27 Dec    16    G0-G1
28 Dec    12    G0, chance of G1

COMMENT: ASWFC Geomagnetic Warning 81 was issued on 25 December 
and is current for 27-28 Dec. G0 geomagnetic conditions were 
observed in the Australian region on UT day 25-Dec. Mostly G0 
geomagnetic conditions were observed in the Antarctic region, 
with a period of G1 observed at Casey. G0 geomagnetic conditions 
are expected on 26-Dec. G0-G1 geomagnetic conditions are expected 
on 27-Dec due to a possible glancing impact from a CME first 
observed on 24-Dec. G0 geomagnetic conditions are expected on 
28-Dec, with a chance of G1 as CME effects abate.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
25 Dec      Normal         Normal         Normal         

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
26 Dec      Normal         Normal         Normal
27 Dec      Normal         Normal-fair    Fair
28 Dec      Normal         Normal         Normal-fair

COMMENT: HF radio communication conditions on UT day 25-Dec were 
mostly normal. Mostly normal conditions are expected over 26-28 
Dec, with normal to fair conditions at middle to high latitudes 
on 27-Dec. Shortwave fadeouts are possible.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
25 Dec   131

Observed Australian Regional MUFs
   Cocos Island Region:
      Mostly near predicted monthly values.
      Enhanced by 20% after local dawn.
   Niue Island Region:
      Enhanced by 25% during local day.
      Enhanced by 15% during local night.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 25% during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 20% 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
26 Dec   125    Near to 15% above predicted monthly values
27 Dec   125    Near to 15% above predicted monthly values
28 Dec   125    Near to 15% above predicted monthly values

COMMENT: ASWFC SWF HF Communications Warning 133 was issued on 
24 December and is current for 24-26 Dec. Maximum usable frequencies 
(MUFs) on UT day 25-Dec in the Australian region were near predicted 
monthly values, with enhancements of up to 25% observed in the 
northern Australian region during local night. MUFs are expected 
to be near predicted monthly values to 15% enhanced over 26-28 
Dec. Shortwave fadeouts are possible.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 24 Dec
       Daily Proton Fluence >1 MeV:   2.2E+04
       Daily Proton Fluence >10 MeV:  1.8E+04
       Daily Electron Fluence >2 MeV: 3.20E+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 24 Dec
Speed: 412 km/sec  Density:    2.7 p/cc  Temp:   140000 K  Bz:   0 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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