[Ips-dsgr] ASWFC Daily Report - 17 October 26 issued 2330 UT on 17 Oct 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun Oct 18 10:30:46 AEDT 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 OCTOBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 OCTOBER AND FORECAST FOR 18 OCTOBER - 20 OCTOBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 17 Oct: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Oct: 132/86
1B. SOLAR FORECAST
18 Oct 19 Oct 20 Oct
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 130/84 125/78 125/78
COMMENT: Solar flare activity was at the R0 level on UT day 17-Oct,
with no significant flares observed. There are currently two
active sunspot regions on the visible disk, with Active Region
(AR) 4551 (S15W32, beta-gamma) being the largest. This region
has exhibited some minor spot decay over the previous UT day.
The other region, AR 4557 (N08E03, beta-gamma), has exhibited
growth over the same period. Solar flare activity is forecast
to be at the R0-R1 level over 18-20 Oct due to the presence of
these two large regions. S0 solar radiation storm conditions
were observed on 17-Oct, with S0 solar radiation storm conditions
forecast over 18-20 Oct. No geoeffective coronal mass ejections
(CMEs) were observed over the past 24 hours. A solar eruption
was visible on the eastern limb in GOES/SUVI 304A imaging from
17/0147UT, with a subsequent east-directed CME observed in SOHO/LASCO
from 17/0236UT. This event has been modelled to pass behind the
Earth and is not geoeffective. The solar wind speed was broadly
constant over 17-Oct, ranging between 430 km/s and 470 km/s throughout
the UT day. The interplanetary magnetic field strength (IMF,
Bt) was also stable, peaking at 8 nT, with the north-south component
(Bz) ranging between -5 and +8 nT. The solar wind is forecast
to decline over 18-Oct, before a rise is expected late on 19-Oct
due to high speed wind stream effects from an equatorial coronal
hole moving into a geoeffective position. The solar wind speed
is forecast to remain elevated over 20-Oct as the Earth continues
to connect with this high speed wind stream.
-----------------------------------------------------------
2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Oct: G0
Estimated Indices 17 Oct : A K
Australian Region 6 21111331
Cocos Island 4 11010231
Darwin 7 22111332
Townsville 6 21111331
Learmonth 6 21011332
Alice Springs 5 21001331
Gingin 6 21111331
Canberra 3 11000321
Kennaook Cape Grim 5 11110331
Hobart 4 11100321
Estimated Antarctic Regional K Indices 17 Oct :
Casey 16 44431232
Mawson 12 33122342
Observed Regional daily pc3 Indices 17 Oct :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 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 17 Oct : A
Fredericksburg 5
Planetary 6
Observed AFr/Ap Indices 16 Oct : A K
Fredericksburg 10
Planetary 12 3222 2342
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Oct 6 G0
19 Oct 10 G0
20 Oct 16 G0, chance of G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on 17-Oct, with G0 conditions also reported in the Antarctic
region, and at the planetary level. G0 planetary geomagnetic
conditions are forecast over 18-20 Oct, with a chance of G1 on
20-Oct due to high speed wind stream effects from an equatorial
coronal hole.
-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Oct Normal Normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Oct Normal Normal Normal
19 Oct Normal Normal Normal
20 Oct Normal Normal Normal-fair
COMMENT: Global high-frequency (HF) radio propagation conditions
were mostly normal on UT day 17-Oct, with fair conditions reported
in high latitude regions. Degradations were also observed in
the southern Australian region early in the UT day. Global HF
conditions are forecast to be mostly normal over 18-20 Oct, with
some mild degradations possible on 20-Oct due to forecast geomagnetic
activity. Shortwave fadeouts are possible.
-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Oct 53
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 20% during local day.
Depressed by 15% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Southern Australian Region:
Depressed by 15% during local day.
Depressed by 15% 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
18 Oct 60 Near predicted monthly values
19 Oct 60 Near predicted monthly values
20 Oct 55 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 89 was issued on
17 October and is current for 18-19 Oct. Maximum Usable Frequencies
(MUFs) were near predicted values in the northern Australian
region on UT day 17-Oct, with some enhancements of up to 15%
also observed. MUFs in the southern Australian region were depressed
by up to 15%, with persistent depressions observed at Canberra.
Strong spread F was observed at Canberra, with sporadic E also
observed at various sites in the Australian region during local
night hours. MUFs are forecast to be near predicted values over
18-20 Oct, with some mild depressions possible in the southern
Australian region on 20-Oct due to forecast geomagnetic activity.
Shortwave fadeouts are possible.
-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Oct
Daily Proton Fluence >1 MeV: 2.9E+05
Daily Proton Fluence >10 MeV: 2.1E+04
Daily Electron Fluence >2 MeV: 3.99E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.7
Solar Wind Day Averaged Data for 16 Oct
Speed: 445 km/sec Density: 4.2 p/cc Temp: 103000 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
More information about the ips-dsgr
mailing list