[Ips-dsgr] ASWFC Daily Report - 17 March 25 issued 2330 UT on 17 Mar 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Mar 18 10:30:55 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 MARCH 2025
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
M1.0 1934UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Mar: 204/155
1B. SOLAR FORECAST
18 Mar 19 Mar 20 Mar
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 188/141 186/139 186/139
COMMENT: Solar activity on UT day 17-Mar was at the R1 level
due to an M1.0 flare at 17/1934UT. There are currently thirteen
numbered active regions on the visible solar disk and two unnumbered
regions. AR4021 (S06W19, beta), AR4025 (N10W20, beta-gamma),
AR4031 (N17W09, beta-gamma) and AR4034 (S17E42,beta-gamma) showed
spot development over the UT day. AR4028 (S18E10, beta-gamma)
is magnetically complex but showed trailer spot simplification.
AR4033 (N26E36, alpha) was responsible for the M1.0 flare at
17/1934UT. An unnumbered region has developed at around N10W32
with beta magnetic characteristics. A further unnumbered region
has rotated onto the solar disk at around N15E80 also with beta
magnetic characteristics. All other regions were either stable
or in decay. Solar activity is expected to be at R0-R1 levels
over 18-20 Mar. S0 solar radiation storm conditions were observed
on UT day 17-Mar. S0 solar radiation storm conditions are mostly
expected over 18-20 Mar. A slow, north directed CME is visible
in SOHO and STEREO-A imagery from 17/0612UT. There is no, clear,
on disk source of this CME. Modelling suggests the majority of
the CME will pass above the Earth, but there is a chance of a
glancing impact at 0600UT on 22-Mar +/- 12 hours. Due to the
slow speed of this CME, any impact is expected to be negligible.
A pair of narrow CMEs directed to the east and west visible in
SOHO imagery from 17/1148UT and 17/1325UT respectively. The later
CME is associated with an eruption on the solar disk at around
N13W34 from 17/1051UT visible in SDO, GOES SUVI and H-Alpha imagery.
The earlier has no obvious connection to on-disk activity. Both
of these CMEs are not expected to be geoeffective. An eruption
on the disk from 17/1918UT is visible in SDO, GOES SUVI and H-Alpha
imagery from 17/1918UT. This eruption is associated with the
M1.0 flare at 17/1934UT. No associated CME is yet visible in
available coronagraph imagery. CME impact analysis will be performed
once more imagery becomes available. Solar wind speed was steady
on 17-Mar with the wind speed mostly ranging between 440 km/s
and 350 km/s. The current wind speed is around 390 km/s. The
peak total interplanetary field strength (IMF, Bt) was 8 nT and
the north-south IMF component range was +6 to -7 nT. The solar
wind environment is expected to be near background levels over
18-19 Mar. An increase in speed is possible early on 20-Mar due
to the arrival of a CME first observed on 16-Mar.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Mar: G0
Estimated Indices 17 Mar : A K
Australian Region 8 22213232
Cocos Island 7 22212231
Darwin 6 22212222
Townsville 7 22222222
Learmonth 9 32213232
Alice Springs 6 22212222
Gingin 12 32213342
Canberra 7 22213222
Kennaook Cape Grim 10 23213332
Hobart 11 23313332
Estimated Antarctic Regional K Indices 17 Mar :
Macquarie Island 19 23435422
Casey 17 44333233
Mawson 40 54533373
Observed Regional daily pc3 Indices 17 Mar :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 2 (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 13
Planetary 17
Observed AFr/Ap Indices 16 Mar : A K
Fredericksburg 10
Planetary 12 2223 4333
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Mar 10 G0
19 Mar 8 G0
20 Mar 16 G0, chance of G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 17-Mar. Mostly G1 geomagnetic conditions were
observed in the Antarctic region, with a period of G3 observed
at Mawson. G0 geomagnetic conditions are expected over 18-19
Mar. G0 conditions, with a chance of G1 are expected on 20-Mar
due to the anticipated arrival of a CME first observed on 16-Mar.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Mar Normal Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Mar Normal Normal Normal-fair
19 Mar Normal Normal Normal-fair
20 Mar Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 17-Mar were
mostly normal, with some degradations visible at the start of
the UT day at mid to high latitudes in the southern hemisphere.
HF radio propagation conditions are expected to be mostly normal
over 18-20 Mar, with the chance of degradations at high latitudes
on 20_mar due to possible geomagnetic activity. Equatorial scintillation
is anticipated due to the proximity to the equinox. Minor shortwave
fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Mar 126
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Niue Island Region:
Enhanced by 30% during local day.
Enhanced by 60% during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Enhanced by 25% after local dawn.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% over the UT day.
Monthly T index:
Month T index
Feb 127
Mar 117
Apr 114
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
18 Mar 135 Near to 15% above predicted monthly values
19 Mar 140 Near to 15% above predicted monthly values
20 Mar 130 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) on UT day 16-Mar were
mostly near predicted values, with enhancements of up to 25%
observed in the northern Australian region. Sporadic-E was observed
at Brisbane, Canberra and Perth. Spread F was observed at Hobart.
MUFs are expected to be near predicted monthly values to 15%
enhanced over 18-19 Mar. MUFs are expected to be near predicted
monthly values on 20-Mar due to possible geomagnetic activity.
Minor shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Mar
Daily Proton Fluence >1 MeV: 6.6E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 1.90E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:15%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.1
DSCOVR Satellite Solar Wind Day Averaged Data for 16 Mar
Speed: 441 km/sec Density: 0.3 p/cc Temp: 66800 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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