[Ips-dsgr] ASWFC Daily Report - 20 April 24 issued 2330 UT on 20 Apr 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sun Apr 21 09:30:56 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 APRIL 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 APRIL AND FORECAST FOR 21 APRIL - 23 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Apr: 210/161
1B. SOLAR FORECAST
21 Apr 22 Apr 23 Apr
Activity R1-R2 R1-R2 R0-R1, chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 210/161 205/156 200/152
COMMENT: Solar activity on UT day 20-Apr was R0, with no significant
solar flares. There are currently twelve numbered sunspots of
the visible solar disk, and several unnumbered. The complex cluster
of sunspots now in the southwestern solar hemisphere continues
to change; the more western spots are growing, while the more
eastern spots are decaying. AR3645 (S08W17, beta-gamma) remains
the most complex region, although the entire cluster has not
produced any significant activity yet. AR3639 (N29W07, beta)
has also shown some growth in the past day. All other sunspot
regions are either stable or decaying. Solar activity over 21-23
Apr is expected to be R1-R2.
The complex cluster of sunspots in the southwest has produced
several C-class flares. Some of these C-class flares have been
associated with narrow and weak CMEs, although the material
appears to be mostly directed to the south. It is not expected
this activity will be significantly geoeffective, although weak
impacts are possible from 24-Apr. No other CMEs were observed today.
S0 solar radiation storm conditions were observed on 20-Apr.
S0 solar radiation storm conditions are expected over 21-23 Apr.
The solar wind environment was enhanced at the beginning of UT
day 20-Apr due to a recent CME arrival and coronal hole wind
stream, however conditions eased throughout the day. The solar
wind speed ranged between 550 down to 410 km/s. The peak total
interplanetary field strength (IMF, Bt) was 7 nT and the north-south
IMF component range (Bz) was +3 to -4 nT. The solar wind may still
be mildly enhanced on 21-Apr as coronal hole effects wane, in addition
to a possible weak glancing blow from a recent CME. Otherwise,
the solar wind speed should tend to background levels over 22-23 Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 Apr: G0
Estimated Indices 20 Apr : A K
Australian Region 7 22232221
Cocos Island 5 12221221
Darwin 7 22232221
Townsville 9 23232222
Learmonth 9 22232322
Alice Springs 7 22232221
Gingin 10 22242321
Canberra 9 22242221
Kennaook Cape Grim 11 22242331
Hobart 11 22242331
Estimated Antarctic Regional K Indices 20 Apr :
Macquarie Island 21 21264431
Casey 10 33331222
Mawson 32 24432655
Observed Regional daily pc3 Indices 20 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (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 20 Apr : A
Fredericksburg 7
Planetary 9
Observed AFr/Ap Indices 19 Apr : A K
Fredericksburg 21
Planetary 46 2155 5574
2B. MAGNETIC FORECAST
Date Ap Conditions
21 Apr 14 G0, slight chance G1
22 Apr 8 G0
23 Apr 6 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 20-Apr. Mostly G0 geomagnetic conditions were
observed in Antarctica, with several periods of G2 observed.
Mostly G0 geomagnetic conditions are expected over 21-23 Apr,
with a slight chance for G1 on 21-Apr due to a weak CME that
was first seen on 18-Apr.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 Apr Normal Fair Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 Apr Normal Normal-fair Fair
22 Apr Normal Normal Normal-fair
23 Apr Normal Normal Normal-fair
COMMENT: HF radio communication on UT day 20-Apr was generally
normal at low latitudes, but degraded near mid to high latitudes
due to a recent geomagnetic storm. HF radio conditions over 21-23
are generally expected to be normal to fair, especially near
high latitudes at local night and dawn hours. Shortwave fadeouts
are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 Apr 130
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 15% during local day.
Enhanced by 70% during local night.
Enhanced by 75% after local dawn.
Niue Island Region:
Mostly near predicted monthly values.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Southern Australian Region:
Depressed by 30% during local day.
Near predicted monthly values during local night.
Antarctic Region (Casey/Davis/Mawson):
Depressed 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
21 Apr 130 Near predicted monthly values to 15-20% depressed
22 Apr 135 Near predicted monthly values to 20% enhanced
in the northern Australian region
23 Apr 135 Near predicted monthly values to 20% enhanced
in the northern Australian region
COMMENT: ASWFC HF Communications Warning 38 was issued on 19
April and is current for 19-21 Apr. ASWFC SWF HF Communications
Warning 39 was issued on 19 April and is current for 20-22 Apr.
Maximum usable frequencies (MUFs) in the northern Australian
region on UT day 20-Apr were near predicted values to 15% enhanced.
MUFs in the southern Australian region were near predicted monthly
values to 30% depressed. Spread-F was observed in Canberra and
Hobart during local night hours. Ionospheric scintillation was
observed near Weipa from 20/1243-1259 UT.
MUFs are expected to
be near predicted monthly values to 20% enhanced in the northern
Australian region over 21-23 Apr. MUFs in the southern Australian
region are expected to be mostly near predicted monthly values
over 21-23 Apr, with some depressions of 15-20% possible during
local night and dawn hours on 21-Apr. Shortwave fadeouts are
possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 Apr
Daily Proton Fluence >1 MeV: 8.8E+05
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 1.00E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.3
DSCOVR Satellite Solar Wind Day Averaged Data for 19 Apr
Speed: 417 km/sec Density: 9.6 p/cc Temp: 88700 K Bz: -6 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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