[Ips-dsgr] ASWFC Daily Report - 21 October 25 issued 2330 UT on 21 Oct 2025 [SEC=OFFICIAL]

Wed Oct 22 10:30:52 AEDT 2025

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 OCTOBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 OCTOBER AND FORECAST FOR 22 OCTOBER - 24 OCTOBER
STATUS INDICATORS SOL:** YELLOW **   MAG:GREEN     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 21 Oct:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Oct: 133/87

1B. SOLAR FORECAST
             22 Oct             23 Oct             24 Oct
Activity     R0-R1              R0-R1              R0-R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   135/89             135/89             140/94

COMMENT: Solar activity on UT day 21-Oct was at the R0 level, 
with no significant flaring activity. There are currently nine 
numbered sunspot regions visible on the solar disk and one unnumbered 
region. AR4259 (S20E24, alpha) has shown mild spot growth. AR4261 
(S07E57, beta) has shown recent decay in its trailer spots. Newly 
numbered AR4264 (N08E58, alpha) recently rotated over the eastern 
limb and is stable. One unnumbered region is visible near S07W45 
(alpha) and has shown recent decay. All other sunspot regions 
are either stable or in decay. Solar activity is expected to 
be at R0-R1 levels over 22-24 Oct due to the possible return 
of previously flare active regions AR4232 and AR4236 on 22-Oct. 
S0 solar proton conditions were observed on UT day 21-Oct. S0 
solar proton conditions are expected over 22-24 Oct. A halo CME 
was observed, visible in LASCO C2 coronagraph imagery from 21/2024UT. 
This CME is considered a farside event and therefore not geoeffective. 
A filament eruption was observed, visible in H-alpha imagery 
from 21/0846UT centred near N32E13. No associated CME has been 
observed in association with this eruption. A second filament 
eruption was observed, visible in H-alpha imagery from 21/1613UT 
centred near N30E45. No CME has been observed associated with 
this eruption. No other Earth-directed CMEs have been observed. 
The solar wind speed on UT day 21-Oct declined, ranging from 
465 to 570 km/s and is currently near 475 km/s. The peak total 
interplanetary magnetic field strength (IMF, Bt) was 7 nT and 
the north-south IMF component (Bz) range was -5 to +6 nT. The 
solar wind speed is expected to decline over 22-24 Oct due to 
waning coronal hole high speed wind stream effects.

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

Geomagnetic field for Australian Region 21 Oct: G0

Estimated Indices 21 Oct : A   K           
   Australian Region       4   22100122
      Cocos Island         2   21100111
      Darwin               7   32110133
      Townsville           5   22101132
      Learmonth            5   32100222
      Alice Springs        4   22100122
      Gingin               5   32100122
      Canberra             5   22100132
      Kennaook Cape Grim   6   22210132
      Hobart               6   22210132    

Estimated Antarctic Regional K Indices 21 Oct :
      Macquarie Island     5   32200122
      Casey               19   45531122
      Mawson              29   34521256

Observed Regional daily pc3 Indices 21 Oct : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin              34   (Quiet to unsettled)
      Canberra            22   (Quiet to unsettled)
      Hobart              23   (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 21 Oct : A 
           Fredericksburg         8
           Planetary              9                         

Observed AFr/Ap Indices 20 Oct :  A   K
           Fredericksburg         6
           Planetary              8   3322 2112     

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
22 Oct     5    G0
23 Oct     6    G0
24 Oct     6    G0

COMMENT: G0 geomagnetic conditions were observed in the Australian 
region on UT day 21-Oct. Mostly G0-G1 geomagnetic conditions 
were observed in the Antarctic region, with an isolated period 
of G2 observed at Mawson. G0 geomagnetic conditions are expected 
over 22-24 Oct.

-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
21 Oct      Normal         Normal         Normal         

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
22 Oct      Normal         Normal         Normal
23 Oct      Normal         Normal         Normal
24 Oct      Normal         Normal         Normal

COMMENT: HF radio propagation conditions on UT day 21-Oct were 
normal. Normal HF conditions are expected over 22-24 Oct. Shortwave 
fadeouts are possible.

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

Date   T index
21 Oct   118

Observed Australian Regional MUFs
   Cocos Island Region:
      Enhanced by 20% during local day.
      Enhanced by 15% during local night.
   Niue Island Region:
      Enhanced by 20% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 20% during local night.
   Southern Australian Region:
      Enhanced 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
Sep      109
Oct      89
Nov      89

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
22 Oct   115    Near to 15% above predicted monthly values
23 Oct   115    Near to 15% above predicted monthly values
24 Oct   115    Near to 15% above predicted monthly values

COMMENT: Maximum usable frequencies (MUFs) in the Australian 
region on UT day 21-Oct were near predicted monthly values to 
20% enhanced. Mild spread F was observed at Hobart during local 
night hours. MUFs are expected to be near predicted monthly values 
to 15% enhanced over 22-24 Oct. Shortwave fadeouts are possible.

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

GOES satellite data for 20 Oct
       Daily Proton Fluence >1 MeV:   1.0E+05
       Daily Proton Fluence >10 MeV:  1.6E+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: C1.2

DSCOVR Satellite Solar Wind Day Averaged Data for 20 Oct
Speed: 531 km/sec  Density:    1.9 p/cc  Temp:   127000 K  Bz:   3 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