[Ips-dsgr] ASWFC Daily Report - 19 May 25 issued 2331 UT on 19 May 2025 [SEC=OFFICIAL]

Tue May 20 09:31:07 AEST 2025

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/19 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 19 MAY AND FORECAST FOR 20 MAY - 22 MAY
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 19 May:  R1

Flares    Max     Fadeout    Freq.  Sectors
  M3.2    0821UT  possible   lower  Mid East/Indian

Observed 10.7 cm flux/Equivalent Sunspot Number for 19 May: 117/69

1B. SOLAR FORECAST
             20 May             21 May             22 May
Activity     R0-R1              R0-R1              R0-R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   118/70             118/70             120/72

COMMENT: Solar activity on UT day 19-May was at the R1 level 
due to an M3.2 flare at 19/0821UT produced by an active region 
beyond the eastern limb. There are currently five numbered sunspot 
regions visible on the solar disk and one unnumbered region. 
AR4087 (N17W08, beta) is the largest region on the disk and has 
shown mild development in its intermediate spots. AR4089 (N17W08, 
beta) has shown decay in its trailer spots and growth in its 
intermediate spots. An unnumbered region recently rotated over 
the eastern limb near S08E80 (alpha) and is stable. All other 
sunspot regions are either stable or in decay. Solar activity 
is expected to be at R0-R1 levels over 20-22 May. No Earth-directed 
CMEs have been observed. A filament eruption was observed, visible 
in GOES SUVI imagery from 18/2217UT, centred near N48E05. A subsequent 
associated northward CME was observed in LASCO C2 coronagraph 
imagery from 19/0012UT. Modelling indicates this CME does not 
contain a geoeffective component. The solar wind speed on UT 
day 19-May declined, ranging from 465 to 615 km/s and is currently 
near 500 km/s. The peak total interplanetary magnetic field strength 
(IMF, Bt) was 8 nT and the north-south IMF component (Bz) range 
was -5 to +7 nT. The solar wind speed is expected to remain elevated 
over 20-22 May due to ongoing coronal hole high speed wind stream 
effects from a southern hemisphere coronal hole.

-----------------------------------------------------------
2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 19 May: G0

Estimated Indices 19 May : A   K           
   Australian Region       5   22113111
      Cocos Island         2   11112100
      Darwin               6   22113212
      Townsville           6   22113112
      Learmonth            7   22223220
      Alice Springs        5   21113111
      Gingin               7   22213221
      Canberra             5   22113111
      Kennaook Cape Grim   6   22113211
      Hobart               5   22113111    

Estimated Antarctic Regional K Indices 19 May :
      Macquarie Island     6   22123211
      Casey               10   33322222
      Mawson              16   44433311

Observed Regional daily pc3 Indices 19 May : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin              21   (Quiet to unsettled)
      Canberra            14   (Quiet)
      Hobart              33   (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 19 May : A 
           Fredericksburg         9
           Planetary             10                         

Observed AFr/Ap Indices 18 May :  A   K
           Fredericksburg        22
           Planetary              0   4353 2443     

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
20 May    16    G0, chance of G1
21 May    14    G0, chance of G1
22 May    12    G0

COMMENT: G0 geomagnetic conditions were observed in the Australian 
and Antarctic regions on UT day 19-May. G0 geomagnetic conditions 
are expected over 20-21 May, with a chance of G1 due to coronal 
hole high speed wind stream effects from a southern hemisphere 
coronal hole. G0 geomagnetic conditions are expected on 22-May.

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

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
20 May      Normal         Normal-fair    Fair
21 May      Normal         Normal         Normal-fair
22 May      Normal         Normal         Normal-fair

COMMENT: HF radio propagation conditions on UT day 19-May were 
normal to fair. HF radio propagation conditions are expected 
to be normal to fair over 20-22 May due to ongoing coronal hole 
effects. Shortwave fadeouts are possible.

-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY

Date   T index
19 May    84

Observed Australian Regional MUFs
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 35% during local night.
   Niue Island Region:
      Enhanced by 15% during local day.
      Depressed by 40% during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 25% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 20% 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
20 May    85    Depressed 15%/near predicted monthly values
21 May    85    Depressed 15%/near predicted monthly values
22 May    85    Depressed 15%/near predicted monthly values

COMMENT: ASWFC SWF HF Communications Warning 49 was issued on 
18 May and is current for 18-20 May. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 19-May were near predicted 
monthly values to 25% depressed. Sporadic E and Spread F were 
observed at Hobart during local night hours. MUFs are expected 
to be near predicted monthly values to 15% depressed over 20-22 
May due to elevated geomagnetic activity. Shortwave fadeouts 
are possible.

-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 18 May
       Daily Proton Fluence >1 MeV:   2.3E+06
       Daily Proton Fluence >10 MeV:  1.6E+04
       Daily Electron Fluence >2 MeV: 3.70E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B4.8

DSCOVR Satellite Solar Wind Day Averaged Data for 18 May
Speed: 644 km/sec  Density:    2.5 p/cc  Temp:   273000 K  Bz:   0 nT

(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------

Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au