[Ips-dsgr] ASWFC Daily Report - 25 April 24 issued 2330 UT on 25 Apr 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Fri Apr 26 09:30:48 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 APRIL 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 25 APRIL AND FORECAST FOR 26 APRIL - 28 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 25 Apr: R1
Flares Max Fadeout Freq. Sectors
M1.1 24/2250UT possible lower East Pacific/
North American
M2.0 24/2259UT possible lower East Pacific/
North American
M1.0 0149UT possible lower West Pacific
M1.0 1321UT possible lower European
M1.3 1712UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Apr: 199/283
1B. SOLAR FORECAST
26 Apr 27 Apr 28 Apr
Activity Moderate Moderate Moderate
Fadeouts Possible Possible Possible
10.7cm/SSN 185/138 170/124 170/124
COMMENT: Solar activity on UT day 25-Apr was R1, with several
M1 level solar flares. A two hour duration M1 flare was observed
from 25/0148 UT from AR3645 (S08W81, beta) and several flares
either at C9 or M1 levels were observed from AR3638 (S18W87,
beta). There are currently fourteen numbered sunspots on the
solar disk. The complex cluster of sunspots in the solar southwestern
quadrant that has featured in this weeks forecasts is nearing
the limb and appears to be decaying, although projection effects
make this region difficult to analyse. AR3656 (S12E24, beta)
is the only region that has shown noteworthy growth over the
past day; all other sunspots are either stable or decaying. Solar
activity is expected to be R1-R2 over 26-28 Apr.
A CME associated
with a prominence eruption was observed on the eastern limb at
25/1100 UT and is not expected to be geoeffective. Two CMEs were
associated with solar flare activity near AR3645 and AR3638,
but due to location these events are not expected to be geoeffective.
No other CMEs were seen on 25-Apr.
S0 solar radiation storm conditions
were observed on 25-Ar. S0 solar radiation storm conditions are
expected over 26-28 Apr.
The solar wind environment on UT day
25-Apr was at background levels. The solar wind speed ranged
between 300-350 km/s. The peak total interplanetary field strength
(IMF, Bt) was 6 nT and the north-south IMF component range (Bz)
was +3 to -4 nT. The solar wind speed is expected to be enhanced
over 26-28 Apr due to a small equatorial coronal hole.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 25 Apr: G0
Estimated Indices 25 Apr : A K
Australian Region 1 11000001
Cocos Island 1 12000001
Darwin 1 20000002
Townsville 2 21000002
Learmonth 1 11010000
Alice Springs 1 10000002
Gingin 1 11000001
Canberra 0 00000001
Kennaook Cape Grim 0 00000001
Hobart 0 00000001
Estimated Antarctic Regional K Indices 25 Apr :
Macquarie Island 0 00010000
Casey 2 02210001
Mawson 5 20000124
Observed Regional daily pc3 Indices 25 Apr :
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 25 Apr : A
Fredericksburg 4
Planetary 4
Observed AFr/Ap Indices 24 Apr : A K
Fredericksburg 9
Planetary 7 2100 2111
2B. MAGNETIC FORECAST
Date Ap Conditions
26 Apr 8 G0, slight chance G1
27 Apr 12 G0, slight chance G1
28 Apr 10 G0, slight chance G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
and Antarctic regions on UT day 25-Apr. Mostly G0 geomagnetic
conditions are expected over 26-28 Apr, with a slight chance
for G1 conditions on these days due to the expected arrival of
a coronal hole high speed wind stream. There is still a slight
possibility that recent CMEs from sunspot regions AR3645 or AR3638
may still arrive at Earth, although this is not expected to be
significant if it eventuates.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
25 Apr Normal-fair Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
26 Apr Normal-fair Normal Normal-fair
27 Apr Normal Normal-fair Normal-fair
28 Apr Normal Normal-fair Normal-fair
COMMENT: HF radio communication conditions were generally normal
at high and middle latitudes. Equatorial scintillation may have
affected low latitudes during local night hours. HF radio communication
conditions are expected to be mostly normal over 26-28 Apr, with
a slight chance for mild degradations during local night and
dawn hours due to expected coronal hole activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
25 Apr 144
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 85% during local night.
Niue Island Region:
Enhanced by 30% during local day.
Enhanced by 65% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Southern Australian Region:
Enhanced by 15% during local day.
Enhanced by 15% during local night.
Antarctic Region (Casey/Davis/Mawson):
Enhanced by 15% over the UT day.
Monthly T index:
Month T index
Mar 120
Apr 114
May 115
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
26 Apr 140 Near predicted monthly values
27 Apr 135 Near predicted monthly values
28 Apr 135 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 41 was issued on
25 April and is current for 25-26 Apr. Maximum usable frequencies
(MUFs) in the Australian region were near predicted monthly values
to 20% enhanced on UT day 25-Apr. Significant signal spreading,
both in range and frequency, was observed in Darwin and Niue
during local night hours. This was likely associated with strong
equatorial scintillation that was observed at Darwin, Niue and
Weipa between 25/0724-1439 UT. Spread-F was also observed in
Hobart during local night hours. MUFs are expected to be near
predicted values over 26-28 Apr, with a slight chance for mild
depressions during local night hours due to possible coronal
hole activity.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 24 Apr
Daily Proton Fluence >1 MeV: 2.3E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 4.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.6
DSCOVR Satellite Solar Wind Day Averaged Data for 24 Apr
Speed: 363 km/sec Density: 0.4 p/cc Temp: 32200 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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