[Ips-dsgr] ASWFC Daily Report - 21 April 24 issued 2330 UT on 21 Apr 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Mon Apr 22 09:30:58 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 APRIL 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 APRIL AND FORECAST FOR 22 APRIL - 24 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Apr: R1
Flares Max Fadeout Freq. Sectors
M1.0 1259UT possible lower European
M2.2 1514UT possible lower South American/
Atlantic
M3.4 2152UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Apr: 217/167
1B. SOLAR FORECAST
22 Apr 23 Apr 24 Apr
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 215/165 215/165 200/152
COMMENT: Solar activity on UT day 21-Apr was R1, with three M
class flares observed. There are currently thirteen numbered
sunspots on the visible solar disk, with several additional regions
currently rotating over the western solar limb. The complex cluster
of sunspots in the southwestern solar hemisphere remained relatively
stable in size and complexity, with some signs of redistribution
observed. All flares observed originated from this cluster. AR3645
(S08W30, beta-gamma) is the largest and the most complex region.
Other regions in the cluster have begun to show signs of decay.
Outside of this cluster, AR3646 (N22E11, beta) and AR3649 (N17W47,
alpha) have shown signs of growth, AR3650 (S11W06, beta) has
shown signs of growth in its intermediate and trailer spots,
and AR3652 (N15E31, beta-gamma) has grown rapidly over UT day
21 -Apr. All other sunspot regions are either stable or decaying.
Solar activity over 22-24 Apr is expected to be R1-R2. Some activity
originating within the complex cluster of sunspots in the southwest
has been associated with narrow and weak CMEs, the material appears
to be mostly directed to the south and west. It is not expected
this activity will be significantly geoeffective, although weak
impacts are possible from 24-Apr. No other significantly geo-effective
CMEs were observed. S0 solar radiation storm conditions were
observed on 21-Apr. S0 solar radiation storm conditions are expected
over 22-24 Apr. The solar wind speed remained slightly enhanced,
increasing slightly across UT day 21-Apr. This increase may be
attributable to a weak glancing arrival of CMEs observed in recent
days. Solar wind speed ranged from 360 to 515 km/s and is currently
at around 455 km/s. The peak total interplanetary field strength
(IMF, Bt) was 8 nT and the north-south IMF component range (Bz)
was +3 to -6 nT. Isolated periods of southward Bz were also observed.
The solar wind may remain mildly enhanced over 22-24 Apr due
to weak glancing blows associated with recent CME activity. Otherwise,
the solar wind speed should tend to background levels over 22-24
Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 Apr: G0
Estimated Indices 21 Apr : A K
Australian Region 15 22244333
Cocos Island 9 22223322
Darwin 11 22234232
Townsville 15 32244332
Learmonth 16 32244333
Alice Springs 14 22244233
Gingin 16 22244334
Canberra 14 22343333
Kennaook Cape Grim 15 23343333
Hobart 17 23344333
Estimated Antarctic Regional K Indices 21 Apr :
Macquarie Island 37 32475442
Casey 13 33233323
Mawson 46 54433755
Observed Regional daily pc3 Indices 21 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 21 Apr : A
Fredericksburg 15
Planetary 19
Observed AFr/Ap Indices 20 Apr : A K
Fredericksburg 10
Planetary 12 2134 2333
2B. MAGNETIC FORECAST
Date Ap Conditions
22 Apr 8 G0-G1
23 Apr 8 G0-G1
24 Apr 8 G0-G1
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 21-Apr. Mostly G0
geomagnetic conditions were observed in Antarctica, with isolated
periods of G2 observed. One period of G3 geomagnetic conditions
was observed in Macquarie Island. G0 geomagnetic conditions are
expected over 22-24 Apr, with a chance for G1 due to the potential
arrival of recently observed CME activity.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 Apr Normal Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 Apr Normal Normal Normal-fair
23 Apr Normal Normal Normal-fair
24 Apr Normal Normal Normal-fair
COMMENT: HF radio communication on UT day 21-Apr was generally
normal at low latitudes, but degraded near mid to high latitudes
due to ongoing impacts of recent geomagnetic storm and CME activity.
HF radio conditions over 22-24 are generally expected to be normal
to fair. Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 Apr 138
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 30% during local night.
Enhanced by 20% after local dawn.
Niue Island Region:
Enhanced by 25% during local day.
Enhanced by 20% 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 20% 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
22 Apr 135 Near predicted monthly values
23 Apr 135 Near predicted monthly values
24 Apr 135 Near 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 northern Australian region on UT day 21-Apr were
near predicted monthly values, with 25% enhancement observed
after local dawn. MUFs in the southern Australian region were
near predicted monthly values. Spread-F was observed in Hobart
during local night hours. Periods of sporadic-E were observed
in Brisbane and Perth. MUFs in the Australian region are expected
to be near predicted monthly values over 22-24 Apr with some
mild depressions possible due to geomagnetic activity. Shortwave
fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 Apr
Daily Proton Fluence >1 MeV: 1.9E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.50E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.7
DSCOVR Satellite Solar Wind Day Averaged Data for 20 Apr
Speed: 459 km/sec Density: 0.8 p/cc Temp: 105000 K Bz: -3 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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