[Ips-dsgr] ASWFC Daily Report - 15 April 26 issued 2330 UT on 15 Apr 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Apr 16 09:30:50 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/15 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 15 APRIL AND FORECAST FOR 16 APRIL - 18 APRIL
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 15 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 15 Apr: 105/54
1B. SOLAR FORECAST
16 Apr 17 Apr 18 Apr
Activity R0 R0 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 110/60 110/60 110/60
COMMENT: Solar flare activity was at the R0 level during UT day
15-Apr. The solar regions currently on the solar disk are small
to medium in size. Solar region AR4419 (N13E44, beta) is the
largest of the on disk regions and is growing. Solar region AR4416
(N19W53, beta) has shown minor development in intermediate spots
and decay in its trailer spots. Solar region AR4415 (S18W21,
alpha) is a stable monopole. There are currently three numbered
regions on the visible solar disk. A faint solar filament located
at approximately S30E10 slowly lifted off the solar disk during
the interval 15/0900-1200UT and on disk plasma motion was also
evident further to the southeast of this location at S40E40.
A broad plasma spray off the northwest solar limb was observed
in GOES 304 imagery from 15/1229UT. S0 solar radiation storm
conditions were observed on 15-Apr. S0 solar radiation storm
conditions are expected for 16-18 Apr. No significantly Earth
directed CMEs have been observed. At the start of the UT day
a non-Earth directed northeast CME was already in progress that
could not be correlated to on disk activity. Southeast directed
CMEs were observed in association with the slow filament eruption(s).
There appeared to be two events with two speeds as longitude
agreement was not possible for the CMEs visible in LASCO and
STEREO-A to be considered as the one event. The slow CME event
more visible in STEREO-A has been modelled as an Earth miss.
The CME event that was more visible is LASCO imagery was faster
and is also modelled as an Earth miss. A northwest CME was also
observed from 15/1148UT which is considered a far side event
associated with the broad northwest limb plasma spray visible
in GOES 304. A large isolated coronal hole located in the northeast
solar quadrant that extends to the south across the solar equator
has started to cross the solar central meridian. The solar wind
speed on UT day 15-Apr slightly declined and ranged from 380
to 340 km/s and is currently at 340 km/s. The peak total interplanetary
magnetic field strength (IMF, Bt) was 5 nT and the north-south
IMF component (Bz) ranged between -5 and +4 nT. The solar wind
speed is expected to remain at background levels on 16-Apr. An
increase in the solar wind speed is expected from late 17-Apr
and on 18-Apr from the large coronal hole now crossing the solar
central meridian, with possible moderate southward fluctuations
of the IMF Bz component prior to and during the entry into the
high speed wind stream.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 15 Apr: G0
Estimated Indices 15 Apr : A K
Australian Region 2 11001111
Cocos Island 1 11000101
Darwin 1 01001111
Townsville 4 21101212
Learmonth 2 01100211
Alice Springs 1 01001101
Gingin 1 10000111
Canberra 1 01001111
Kennaook Cape Grim 2 11001211
Hobart 3 --101211
Estimated Antarctic Regional K Indices 15 Apr :
Macquarie Island 1 00000111
Casey 7 23311211
Mawson 14 12211226
Observed Regional daily pc3 Indices 15 Apr :
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 15 Apr : A
Fredericksburg 4
Planetary 5
Observed AFr/Ap Indices 14 Apr : A K
Fredericksburg 2
Planetary 4 2001 1100
2B. MAGNETIC FORECAST
Date Ap Conditions
16 Apr 5 G0
17 Apr 18 G0, chance G1 late in UT day.
18 Apr 30 G1, chance G2
COMMENT: ASWFC Geomagnetic Warning 28 was issued on 15 April
and is current for 17-19 Apr. G0 geomagnetic conditions were
observed in the Australian and Antarctic regions on UT day 15-Apr.
G0 geomagnetic conditions are expected for 16-Apr and most of
17 Apr. A coronal hole wind stream is expected to increase geomagnetic
activity possibly to G1 from late 17-Apr with G1, chance G2 conditions
expected on 18-Apr.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
15 Apr Normal Fair-normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
16 Apr Normal Normal Normal
17 Apr Normal Normal-fair Normal-fair
18 Apr Normal Fair Fair-poor
COMMENT: HF radio propagation conditions were fair to normal
on 15-Apr. Fair to normal HF conditions are expected 16-17 Apr
with degraded conditions expected for middle to high latitudes
from 18-Apr due to anticipated geomagnetic activity from a coronal
hole wind stream.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
15 Apr 61
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 35% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Depressed by 20% after local dawn.
Northern Australian Region:
Mostly near predicted monthly values.
Southern Australian Region:
Near predicted monthly values during local day.
Depressed by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Mar 92
Apr 83
May 81
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
16 Apr 70 Depressed 10 to 15%/near predicted monthly values
17 Apr 70 Depressed 10 to 15%/near predicted monthly values
18 Apr 70 Depressed 10 to 15%/near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) in the Australian
region on UT day 15-Apr were depressed 20% to near predicted
values. Spread-F was observed at Hobart and Canberra during local
night hours. MUFs are expected to be 15% depressed to near predicted
monthly values over 16-18 Apr. Degraded HF conditions may be
experienced for the southern Australian region from 18-Apr in
association with anticipated geomagnetic activity induced by
a coronal hole wind stream.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 14 Apr
Daily Proton Fluence >1 MeV: 3.9E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 8.50E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:10%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B2.8
DSCOVR Satellite Solar Wind Day Averaged Data for 14 Apr
Speed: 370 km/sec Density: 2.5 p/cc Temp: 35500 K Bz: 0 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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