[Ips-dsgr] ASWFC Daily Report - 16 May 25 issued 2330 UT on 16 May 2025 [SEC=OFFICIAL]

Sat May 17 09:30:58 AEST 2025

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/16 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 16 MAY AND FORECAST FOR 17 MAY - 19 MAY
STATUS INDICATORS SOL:** RED **   MAG:** YELLOW **     ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 16 May:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 16 May: 117/69

1B. SOLAR FORECAST
             17 May             18 May             19 May
Activity     R1-R2              R1-R2              R1-R2
Fadeouts     Probable           Probable           Probable
10.7cm/SSN   118/70             118/70             120/72

COMMENT: Solar activity on UT day 16-May was at the R0 level 
with a declining background X-Ray flux. There are currently four 
numbered sunspot regions visible on the solar disk. AR4087 (N17E30, 
beta-gamma-delta) is the largest and most magnetically complex 
region on the solar disk and has been responsible for several 
M-class flares and one X-class flare since arriving on the solar 
disk. This region appeared stable over the UT day. Newly numbered 
regions AR4089 (N16E53, beta) and AR4090 (S12E63, alpha) both 
showed spot development over the UT day. AR4088 (N08W64, alpha) 
appeared stable. Solar activity is expected to be at R1-R2 levels 
over 17-19 May. S0 solar radiation conditions were observed on 
16-May, S0 conditions are expected over 17-19 May. No Earth-directed 
CMEs have been observed. The solar wind speed on UT day 16-May 
was stable, mostly ranging between 370 to 450 km/s and is currently 
near 425 km/s. The peak total interplanetary magnetic field strength 
(IMF, Bt) was 11 nT and the north-south IMF component (Bz) range 
was -11 to +12 nT. A sustained period of significant -Bz began 
at 16/2100UT and is ongoing. A southern hemisphere coronal hole 
is currently crossing the central meridian and is expected to 
influence the solar wind speed on 18-May. The solar wind speed 
is expected to remain near current levels on 17-May, then increase 
over 18-19 May due to coronal hole high speed wind stream effects.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 16 May: G0

Estimated Indices 16 May : A   K           
   Australian Region      10   22322323
      Cocos Island         6   22212212
      Darwin              10   22322323
      Townsville          11   22332323
      Learmonth            8   22212323
      Alice Springs        8   22322312
      Gingin              10   22322323
      Canberra             9   22332312
      Kennaook Cape Grim  11   22332323
      Hobart              10   22332313    

Estimated Antarctic Regional K Indices 16 May :
      Macquarie Island    24   23555322
      Casey               11   34212223
      Mawson              23   44333345

Observed Regional daily pc3 Indices 16 May : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            2   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin              24   (Quiet to unsettled)
      Canberra            19   (Quiet)
      Hobart              18   (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 May : A 
           Fredericksburg         9
           Planetary             11                         

Observed AFr/Ap Indices 15 May :  A   K
           Fredericksburg         0
           Planetary              0   3432 2323     

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
17 May     8    G0
18 May    18    G0-G1
19 May    16    G0, chance of G1

COMMENT: G0 geomagnetic conditions were observed in the Australian 
region on UT day 16-May. Mostly G1 geomagnetic conditions were 
observed in the Antarctic region. G0 geomagnetic conditions are 
expected on 17-May. G0-G1 conditions are expected on 18-May and 
G0 conditions, with a chance of G1 are expected on 19-May due 
to anticipated coronal hole high speed wind stream effects.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
16 May      Normal         Normal-fair    Fair           

PCA Event : No event.

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

COMMENT: HF radio propagation conditions on UT day 16-May were 
mostly fair at high latitudes, and normal to fair at middle and 
low latitudes. HF radio propagation conditions are expected to 
be mostly normal to fair over 17-18 May, degradations are possible 
from late on 18-May to 19-May due to anticipated coronal hole 
high speed wind stream effects. Shortwave fadeouts are probable.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY

Date   T index
16 May    89

Observed Australian Regional MUFs
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 25% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 35% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 25% during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
      Depressed by 25% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

Monthly T index:
Month  T index
Apr      123
May      113
Jun      111

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
17 May    90    Depressed 20%/near predicted monthly values
18 May    90    Depressed 20%/near predicted monthly values
19 May    90    Depressed 20%/near predicted monthly values

COMMENT: ASWFC HF Communications Warning 48 was issued on 16 
May and is current for 17-19 May. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 16-May were depressed 
by 25-30% during local night and were near predicted monthly 
values during local day. Spread F was observed at Hobart, Canberra 
and Brisbane during local night hours. MUFs are expected to be 
near predicted monthly values to 20% depressed over 17-19 May. 
Shortwave fadeouts are probable.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 15 May
       Daily Proton Fluence >1 MeV:   4.9E+05
       Daily Proton Fluence >10 MeV:  1.6E+04
       Daily Electron Fluence >2 MeV: 1.50E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B5.0

DSCOVR Satellite Solar Wind Day Averaged Data for 15 May
Speed: 437 km/sec  Density:    3.5 p/cc  Temp:   113000 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