[Ips-dsgr] ASWFC Daily Report - 23 April 24 issued 2330 UT on 23 Apr 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Wed Apr 24 09:30:55 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 APRIL 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 23 APRIL AND FORECAST FOR 24 APRIL - 26 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 23 Apr: R1
Flares Max Fadeout Freq. Sectors
M1.0 22/2318UT possible lower West Pacific
M3.6 0319UT possible lower E. Asia/Aust.
M3.0 0821UT possible lower Mid East/Indian
M1.0 1651UT possible lower South American/
Atlantic
M2.9 1744UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 23 Apr: 214/165
1B. SOLAR FORECAST
24 Apr 25 Apr 26 Apr
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 215/165 210/161 190/143
COMMENT: Solar activity on UT day 23-Apr was at the R1 level
due to three low level M-class flares, the largest of which was
an M3.6 flare at 23/0319UT from AR3654 (S09E37, beta), with AR3645
(S08W57, beta) and AR3646 (N22W15, gamma) also contributing to
the X-ray flux of this flare. There are currently 15 numbered
active regions visible on the solar disk and two unnumbered regions.
AR3645 is the largest region and has shown decay in its trailer
spots. AR3647 (S13W52, gamma) and AR3648 (N18W28, beta) have
both exhibited spot development over the UT day. AR3646 has shown
growth in its leader spot whilst its intermediate spots have
decayed. AR3656 (S12E49, beta) has shown mild growth in its trailer
spots. An unnumbered region is visible near S25W05 (alpha) which
has shown recent decay. A second unnumbered region is visible
near S16E25 (beta) which has shown spot growth. All other active
regions are either stable or in decay. Solar activity is expected
to be at R1-R2 levels over 24-26 Apr. Several CMEs were observed,
but none are considered geoeffective. A small filament eruption
was observed, visible in SDO imagery at 23/0328UT near S22E01.
An associated southward CME was observed in STEREO-A coronagraph
imagery from 23/0438UT. Modelling indicates this CME will pass
underneath the Earth and is therefore not considered geoeffective.
A broad southwest-directed CME was observed, visible in LASCO
C2 coronagraph imagery from 23/1800UT. This CME is associated
with the M2.9 flare observed at 23/1744UT. Modelling indicates
this CME will pass ahead of the Earth and is not geoeffective.
The solar wind speed on UT day 23-Apr was mostly stable, ranging
from 350 to 425 km/s and is currently near 370 km/s. The peak
total interplanetary field strength (IMF, Bt) was 6 nT and the
north south IMF component (Bz) range was +6 to -6 nT. A small
equatorial coronal hole is currently visible in the western hemisphere
and may influence the solar wind speed over the coming days.
The solar wind speed is expected to mildly increase over 24-26
Apr due to the combined effects of a coronal hole high speed
wind stream and possible weak CME arrivals.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 23 Apr: G0
Estimated Indices 23 Apr : A K
Australian Region 5 22222011
Cocos Island 3 12221010
Darwin 5 21222012
Townsville 5 21222012
Learmonth 6 22223020
Alice Springs 4 21222011
Gingin 6 22223021
Canberra 5 11223012
Kennaook Cape Grim 6 22223021
Hobart 6 12223021
Estimated Antarctic Regional K Indices 23 Apr :
Macquarie Island 8 11144011
Casey 9 33313111
Mawson 18 33222155
Observed Regional daily pc3 Indices 23 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 23 Apr : A
Fredericksburg 11
Planetary 15
Observed AFr/Ap Indices 22 Apr : A K
Fredericksburg 0
Planetary 0 2322 1222
2B. MAGNETIC FORECAST
Date Ap Conditions
24 Apr 12 G0, chance of G1
25 Apr 8 G0
26 Apr 8 G0
COMMENT: ASWFC Geomagnetic Warning 16 was issued on 21 April
and is current for 21-24 Apr. G0 geomagnetic conditions were
observed in the Australian region on UT day 23-Apr. Mostly G0
geomagnetic conditions were observed in the Antarctic region,
with an isolated period of G1 observed at Mawson. G0 geomagnetic
conditions are expected over 24-26 Apr, with a chance of G1 on
24-Apr due to possible weak glancing CME arrivals.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
23 Apr Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
24 Apr Normal Normal Normal-fair
25 Apr Normal Normal Normal-fair
26 Apr Normal Normal Normal-fair
COMMENT: HF radio communication conditions on UT day 23-Apr were
normal. Mostly normal HF conditions are expected over 24-26 Apr.
Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
23 Apr 142
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 15% during local day.
Enhanced by 80% during local night.
Enhanced by 20% after local dawn.
Niue Island Region:
Enhanced by 20% during local day.
Enhanced by 40% during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Enhanced by 20% after local dawn.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values 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
24 Apr 140 Near to 15% above predicted monthly values
25 Apr 140 Near to 15% above predicted monthly values
26 Apr 140 Near to 15% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 40 was issued on
21 April and is current for 22-24 Apr. Maximum usable frequencies
(MUFs) in the Australian region on UT day 23-Apr were near predicted
monthly values to 15-20% enhanced. Spread-F was observed at Hobart
and Perth during local night hours. MUFs in the Australian region
are expected to be near predicted monthly values to 15% enhanced
over 24-26 Apr. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 22 Apr
Daily Proton Fluence >1 MeV: 9.7E+04
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C3.3
DSCOVR Satellite Solar Wind Day Averaged Data for 22 Apr
Speed: 424 km/sec Density: 0.3 p/cc Temp: 124000 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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