[Ips-dsgr] ASWFC Daily Report - 19 March 26 issued 2330 UT on 19 Mar 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Mar 20 10:30:50 AEDT 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/19 MARCH 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 19 MARCH AND FORECAST FOR 20 MARCH - 22 MARCH
STATUS INDICATORS SOL:GREEN MAG:** RED ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 19 Mar: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 19 Mar: 106/55
1B. SOLAR FORECAST
20 Mar 21 Mar 22 Mar
Activity R0 R0 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 105/54 105/54 100/48
COMMENT: Solar activity on UT day 19-Mar was R0, with no significant
flares observed. Solar region AR4392 (S15W18, beta) which recently
produced isolated R1 flare activity is now showing decay in the
small spots surrounding its larger main spot and has also reduced
in magnetic complexity. This region produced an isolated low
level C2.3 flare at 19/0558UT. Small region AR4397 (N16E59, beta)
continues to grow but has been flare quiet, though some complexity
may be developing in its leader spot. There are currently two
numbered sunspot regions on the solar disk. Solar activity is
expected to be R0 over 20-22 Mar. No Earth directed CMEs were
observed on UT day 19-Mar. A minor northeast (non Earth directed)
CME was observed from 19/1512UT that could not be correlated
to any on disk activity, perhaps associated with a northeast
solar limb prominence eruption visible in GOES SUVI imagery.
S0 solar radiation storm conditions were observed on UT day 19-Mar.
S0 solar radiation storm conditions are expected over 20-22 Mar.
A coronal hole is visible in the northern solar hemisphere and
is crossing the solar central meridian. Another coronal hole
is visible in the southern solar hemisphere that has now mostly
crossed the solar central meridian. On UT day 19-Mar the solar
wind speed further declined to near background levels as the
influence of a recent coronal hole wind stream ends. The solar
wind shock expected late in the UT day on 19-Mar due to the anticipated
arrival of a M2.7 flare/CME that was observed on 16-Mar has yet
to eventuate. Two CME arrivals are now expected on 20-Mar. However,
the ACE EPAM low energy ion channel which typically shows an
increasing flux trend before the arrival of the more Earth direct
CMEs is currently flat, perhaps suggesting CME arrivals more
in the second half of the UT day 20-Mar or that the CME arrival
will be less direct than modelling suggested. In addition, solar
wind 27 day recurrence patterns suggest coronal hole wind streams
are likely to increase the solar wind speed over 21-23 Mar. The
solar wind speed ranged from 334 km/s to 400 km/s and is currently
at 356 km/s. The peak total interplanetary field strength (IMF,
Bt) was 6 nT. The north-south IMF component range (Bz) was +3
to -2 nT. No CME interplanetary magnetic field enhancement was
observed on 19-Mar.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 19 Mar: G0
Estimated Indices 19 Mar : A K
Australian Region 1 01101000
Cocos Island 1 11100000
Darwin - --------
Townsville 1 11101001
Learmonth 0 01001000
Alice Springs 1 01101001
Gingin 0 01001000
Canberra 1 11001000
Kennaook Cape Grim 1 01102000
Hobart 1 01101000
Estimated Antarctic Regional K Indices 19 Mar :
Macquarie Island 0 00000000
Casey 4 23221000
Mawson 1 11110000
Observed Regional daily pc3 Indices 19 Mar :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 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 19 Mar : A
Fredericksburg 9
Planetary 13
Observed AFr/Ap Indices 18 Mar : A K
Fredericksburg 4
Planetary 5 1122 1112
2B. MAGNETIC FORECAST
Date Ap Conditions
20 Mar 35 G1-G2
21 Mar 25 G1-G2
22 Mar 20 G1
COMMENT: ASWFC Geomagnetic Warning 17 was issued on 19 March
and is current for 19-23 Mar. Geomagnetic conditions in the Australian
region on UT day 19-Mar were G0. Conditions in the Antarctic
region were G0. The first CME arrival expected late on 19-Mar
has failed to eventuate. Two CME arrivals are now expected on
20-Mar. G1-G2 geomagnetic conditions are expected 20-21 Mar due
to CME induced geomagnetic activity. In addition coronal hole
wind streams are expected to contribute to geomagnetic activity
over 21-23 Mar.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
19 Mar Normal Normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
20 Mar Normal Fair Fair-poor
21 Mar Fair Fair Fair-poor
22 Mar Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 19-Mar were
fair to normal. The anticipated degradation in HF conditions
late in the UT day 19-Mar has failed to eventuate. Two CME arrivals
are now expected on 20-Mar. HF radio propagation conditions are
expected to be initially normal on 20-Mar then becoming poor
to fair at middle to high latitudes due to anticipated geomagnetic
activity from two CME arrivals and also coronal hole wind streams
onset on 21-Mar.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
19 Mar 83
Observed Australian Regional MUFs
Cocos Island Region:
Mostly near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Depressed by 25% during local night.
Southern Australian Region:
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
20 Mar 75 Initially near predicted monthly values then
becoming depressed by up to 20%
21 Mar 55 Depressed by up to 20%
22 Mar 65 Depressed 10 to 15%/near predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 27 was issued
on 19 March and is current for 20-21 Mar. Maximum usable frequencies
(MUFs) in the Australian region on UT day 19-Mar were near predicted
monthly values during the local day with depressions of 25% at
times during local night hours in the northern Australian region.
These lower latitude ionospheric depressions were not related
to any geomagnetic activity. Spread F was observed at Hobart
during local night hours. Equatorial scintillation was observed
at Niue 19/0722-0759UT. The anticipated geomagnetic storm activity
expected to start from late in the UT day on 19-Mar with subsequent
post dawn middle latitude ionospheric MUF depressions on 20-Mar
has not eventuated. MUFs are now expected to be near predicted
monthly values for most of the UT day 20-Mar, then becoming 20%
depressed later in the UT day (after local dawn 21-Mar). Southern
Australian regional MUFs are expected to be depressed by up to
15-20% over 21-Mar to 22-Mar due to an anticipated increase in
geomagnetic activity from two CME arrivals and coronal hole wind
streams.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 18 Mar
Daily Proton Fluence >1 MeV: 8.6E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.60E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:14%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B3.8
DSCOVR Satellite Solar Wind Day Averaged Data for 18 Mar
Speed: 409 km/sec Density: 1.0 p/cc Temp: 47600 K Bz: 2 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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