[Ips-dsgr] ASWFC Daily Report - 17 March 26 issued 2330 UT on 17 Mar 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Mar 18 10:30:45 AEDT 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 MARCH 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 MARCH AND FORECAST FOR 18 MARCH - 20 MARCH
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 Mar: R1
Flares Max Fadeout Freq. Sectors
M1.3 0904UT possible lower Mid East/Indian
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Mar: 111/62
1B. SOLAR FORECAST
18 Mar 19 Mar 20 Mar
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 112/63 110/60 110/60
COMMENT: Solar activity on UT day 17-Mar was R1, with an isolated
M1.3 class solar flare from active region (AR) 4392 (S15E016,
beta). There are currently five numbered sunspot regions on the
solar disk. Most regions have gone through another growth phase
in the past day, which was followed by a decay phase. AR4392
is the largest region on the disk, but overall does not show
significant magnetic complexity. Solar activity is expected to
be R0-R1 over 18-20 Mar.
A narrow CME can be seen from 0638 UT in STEREO-A imagery only,
although the source of this event is not clear. If this event is
from the frontside of the Sun, it may have a weak impact late on 19-Mar,
along with another CME.
S0 solar radiation storm conditions were observed on UT day 17-Mar.
S0 solar radiation storm conditions are expected over 18-20 Mar.
On UT day 17-Mar the solar wind environment was undisturbed,
as the solar wind speed continued to decline from the recent
coronal hole event. The solar wind speed ranged from near 500
km/s trending to 450 km/s. The peak total interplanetary field
strength (IMF, Bt) was 5 nT. The north-south IMF component range
(Bz) was +4 to -3 nT. The solar wind environment is expected
to be near background conditions on 18-Mar. By late 19-Mar a
recent CME is expected to arrive, with effects continuing into
20-Mar.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Mar: G0
Estimated Indices 17 Mar : A K
Australian Region 2 21100001
Cocos Island 2 12110000
Darwin 6 42201012
Townsville 3 22111011
Learmonth 3 22101011
Alice Springs 2 21100001
Gingin 2 21101000
Canberra 1 11100000
Kennaook Cape Grim 1 11110000
Hobart 2 11210000
Estimated Antarctic Regional K Indices 17 Mar :
Macquarie Island 1 11020000
Casey 10 34421101
Mawson 5 23311010
Observed Regional daily pc3 Indices 17 Mar :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 14 (Quiet)
Canberra 11 (Quiet)
Hobart 6 (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 Mar : A
Fredericksburg 6
Planetary 7
Observed AFr/Ap Indices 16 Mar : A K
Fredericksburg 10
Planetary 10 3322 3221
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Mar 6 G0
19 Mar 16 G1-G2
20 Mar 20 G1-G2
COMMENT: ASWFC Geomagnetic Warning 16 was issued on 17 March
and is current for 19-20 Mar. Geomagnetic conditions in the Australian
region on UT day 17-Mar were G0. Conditions in the Antarctic
region were G0. G0 geomagnetic conditions are expected on 18-Mar.
On 19-Mar, a CME is expected to arrive at 1800 UT +/- 10 hours.
G1-G2 geomagnetic conditions are expected after arrival, which
will likely continue into 20-Mar.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Mar Normal-fair Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Mar Normal Normal Normal
19 Mar Normal Normal-fair Fair
20 Mar Normal-fair Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 17-Mar were
mildly degraded. HF radio propagation conditions are expected
to be mostly normal on 18-Mar. HF conditions may become mildly
degraded late on 19-Mar, and remain degraded on 20-Mar.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Mar 85
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Niue Island Region:
Near predicted monthly values.
Northern Australian Region:
Enhanced by 20% during local day.
Near predicted monthly values during local night.
Southern Australian Region:
Mostly near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Feb 98
Mar 87
Apr 85
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
18 Mar 90 Near predicted monthly values
19 Mar 90 Near predicted monthly values to 15% depressed
20 Mar 80 Near predicted monthly values to 20% depressed
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 17-Mar were near predicted values to 20% enhanced.
Some spread-F was observed in Hobart during local night hours.
Scintillation was observed in Darwin from 1151 to 1526UT. MUFs
are expected to be mostly normal over 18-19 Mar, however due
to an anticipated geomagnetic disturbance late on 19-Mar conditions
may became mildly depressed upon commencement. MUFs may be depressed
up to 20% on 20-Mar.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Mar
Daily Proton Fluence >1 MeV: 1.2E+06
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 7.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 9%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B3.2
DSCOVR Satellite Solar Wind Day Averaged Data for 16 Mar
Speed: 539 km/sec Density: 0.3 p/cc Temp: 99000 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
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