[Ips-dsgr] ASWFC Daily Report - 19 October 26 issued 2330 UT on 19 Oct 2026 [SEC=OFFICIAL]

Tue Oct 20 10:30:46 AEDT 2026

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/19 OCTOBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 19 OCTOBER AND FORECAST FOR 20 OCTOBER - 22 OCTOBER
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 19 Oct:  R1

Flares    Max     Fadeout    Freq.  Sectors
  M1.6    0903UT  possible   lower  Mid East/Indian

Observed 10.7 cm flux/Equivalent Sunspot Number for 19 Oct: 121/73

1B. SOLAR FORECAST
             20 Oct             21 Oct             22 Oct
Activity     R0-R1              R0-R1              R0-R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   120/72             120/72             115/66

COMMENT: Solar flare activity on UT day 19-Oct was at the R1 
level due to an M1.6 flare at 19/0903UT produced by Active Region 
(AR) 4551 (S15W57, beta-gamma). There are currently three numbered 
sunspot regions visible on the solar disk. AR 4551 is the largest 
on the disk and has shown decay in its intermediate spots. Region 
4557 (N08W22, beta) has exhibited growth in its intermediate 
spots and decay in its trailer spots. AR 4560 (N13E02, beta) 
has shown spot development across the UT day. Solar flare activity 
is expected to be at R0-R1 levels over 20-22 Oct due to the size, 
complexity and observed activity of region 4551. S0 solar radiation 
storm conditions were observed on UT day 19-Oct. S0 solar radiation 
storm conditions are expected over 20-22 Oct. No Earth-directed 
coronal mass ejections (CMEs) have been observed. The solar wind 
speed on UT day 19-Oct mildly declined, ranging between 405 and 
355 km/s, and is currently near 355 km/s. The peak total interplanetary 
magnetic field strength (IMF, Bt) was 6 nT and the north-south 
IMF component (Bz) ranged between -3 to +5 nT. The solar wind 
speed is expected to increase on 20-Oct due to coronal hole high-speed 
wind stream effects, and remain elevated over 21-22 Oct.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 19 Oct: G0

Estimated Indices 19 Oct : A   K           
   Australian Region       1   11000101
      Cocos Island         0   01000100
      Darwin               2   10100112
      Townsville           2   21100111
      Learmonth            1   11000101
      Alice Springs        1   11000101
      Gingin               0   10000001
      Canberra             0   01000001
      Kennaook Cape Grim   1   11000001
      Hobart               1   11000001    

Estimated Antarctic Regional K Indices 19 Oct :
      Casey                6   33221011
      Mawson               6   11022104

Observed Regional daily pc3 Indices 19 Oct : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra            19   (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 19 Oct : A 
           Fredericksburg         5
           Planetary              8                         

Observed AFr/Ap Indices 18 Oct :  A   K
           Fredericksburg         4
           Planetary              6   2222 0120     

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
20 Oct    18    G0, chance of G1
21 Oct    12    G0
22 Oct    10    G0

COMMENT: G0 geomagnetic conditions were observed in the Australian 
and Antarctic regions on UT day 19-Oct. G0 conditions were also 
observed at the planetary level. G0 planetary geomagnetic conditions 
are expected over 20-22 Oct, with a chance of G1 on 20-Oct due 
to coronal hole high-speed wind stream effects.

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

PCA Event : No event.

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

COMMENT: Global high-frequency (HF) radio propagation conditions 
were normal to fair on UT day 20-Oct, with fair conditions observed 
in mid and low latitude regions during local day. Global HF propagation 
conditions are forecast to be normal to fair on 20-Oct due to 
forecast geomagnetic activity, then mostly normal over 21-22 
Oct. Shortwave fadeouts are possible.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY

Date   T index
19 Oct    47

Observed Australian Regional MUFs
   Cocos Island Region:
      No data available during local day.
      No data available during local night.
   Niue Island Region:
      Mostly near predicted monthly values.
   Northern Australian Region:
      Depressed by 20% during local day.
      Near predicted monthly values during local night.
   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
Sep      61
Oct      60
Nov      58

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
20 Oct    45    Near predicted monthly values
21 Oct    50    Near predicted monthly values
22 Oct    50    Near predicted monthly values

COMMENT: Maximum Usable Frequencies (MUFs) in the Australian 
region were near predicted monthly values during local night 
and 15-20% depressed during local day on UT day 19-Oct. Spread 
F was observed at Hobart during local night hours. MUFs are forecast 
to be near predicted monthly values over 20-22 Oct, with some 
mild depressions possible on 20-Oct due to forecast geomagnetic 
activity. Shortwave fadeouts are possible.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 18 Oct
       Daily Proton Fluence >1 MeV:   1.5E+05
       Daily Proton Fluence >10 MeV:  2.1E+04
       Daily Electron Fluence >2 MeV: 2.00E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B5.2

Solar Wind Day Averaged Data for 18 Oct
Speed: 464 km/sec  Density:    2.6 p/cc  Temp:   292000 K  Bz:   1 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