[Ips-dsgr] ASWFC Daily Report - 19 April 24 issued 2330 UT on 19 Apr 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sat Apr 20 09:30:57 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/19 APRIL 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 19 APRIL AND FORECAST FOR 20 APRIL - 22 APRIL
STATUS INDICATORS SOL:** RED ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 19 Apr: Moderate
Flares Max Fadeout Freq. Sectors
M2.1 0453UT possible lower E. Asia/Aust.
M1.0 1307UT possible lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 19 Apr: 213/164
1B. SOLAR FORECAST
20 Apr 21 Apr 22 Apr
Activity R1-R2, chance R3 R1-R2, chance R3 R1-R2, chance R3
Fadeouts Probable Probable Probable
10.7cm/SSN 220/170 220/170 215/165
COMMENT: Solar activity on UT day 19-Apr was R1, with an isolated
M2 level solar flare. Current sunspot activity on the visible
solar disk is complex. There are a cluster of sunspots that have
crossed the central meridian in the southern solar hemisphere
near S10. The predominant sunspot in this group is AR3645 (S08W04,
beta-gamma) which has grown in size and complexity over the past
day. The other sunspots surrounding this one have also shown
growth in size and complexity, notably AR3647 (S13W00, beta-gamma)
and AR3650 (S11E20, beta). A sunspot in the northern solar hemisphere
AR3639 (N29E04, beta-gamma) has also shown growth in the past
day. All other sunspots are either stable or in decay. Solar
activity over 20-22 Apr is expected to be R1-R2 with a chance
for R3.
CME activity on UT day 19-Apr was complex. A large prominence
slowly lifted off the south east solar limb from approximately
19/0529 UT and was associated with a slow southeastern CME that
is not expected to be geoeffective. Associated with the M2 solar
flare from AR3645 was a weak CME that was directed south/ southeast
from 19/0417 UT, this may have an impact to Earth by 24-Apr although
modelling of this event is not reliable. A very weak halo CME
was associated with an M1 flare from AR3645 at 19/1325 UT and
may have a weak impact on 24-Apr. A large prominence eruption
on the eastern solar limb was associated with a CME from 19/1853
UT, but is not expected to be geoeffective.
S0 solar radiation storm conditions were observed on 19-Apr.
S0 solar radiation storm conditions are expected over 20-22 Apr,
although this may be upgraded depending on the activity of AR3645.
A weak shock was detected in the solar wind at 19/0454 UT, signalling the
arrival of a recent CME. The solar wind gradually increased throughout
the UT day 19-Apr and ranged between 330 km/s at the start, and
500 km/s by the end of the day. The peak total interplanetary
field strength (IMF, Bt) was 18 nT and the north-south IMF component
range (Bz) was +8 to -17 nT. Solar wind parameter Bz was oriented
southward from the 19/0410 UT onwards, and has only just begun
to ease to northward from approximately 19/1910 UT. A weak coronal
hole currently near W30-40 may be contributing to increased solar
wind conditions. The solar wind environment is expected to remain
elevated over 20-21Apr, before beginning to return to background
levels on 22 Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 19 Apr: G0
Estimated Indices 19 Apr : A K
Australian Region 19 22344443
Cocos Island 15 12334343
Darwin 14 22334333
Townsville 9 223-----
Learmonth 20 22334453
Alice Springs 12 22333332
Gingin 20 21333553
Canberra 14 12343342
Kennaook Cape Grim 17 12344442
Hobart 25 12454453
Estimated Antarctic Regional K Indices 19 Apr :
Macquarie Island 41 12555663
Casey 14 33333332
Mawson 32 22554455
Observed Regional daily pc3 Indices 19 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 4 (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 19 Apr : A
Fredericksburg 24
Planetary 43
Observed AFr/Ap Indices 18 Apr : A K
Fredericksburg 5
Planetary 4 1100 1112
2B. MAGNETIC FORECAST
Date Ap Conditions
20 Apr 15 G0, chance G1
21 Apr 10 G0, chance G1
22 Apr 8 G0
COMMENT: ASWFC Geomagnetic Warning 15 was issued on 19 April
and is current for 19-20 Apr. G0 geomagnetic conditions were
observed in the Australian region on UT day 19-Apr, although
several individual sites recorded periods of G1. G1-G2 geomagnetic
conditions were observed in Antarctica on 19-Apr. G3 geomagnetic
conditions were observed as a planetary average on 19-Apr from
1800 UT. This geomagnetic activity can be attributed to the arrival
of a recent CME and possibly a weak coronal hole wind stream.
Geomagnetic conditions is expected to be G0 over 20-22 Apr, with
a chance for isolated periods of G1 on 20-Apr due to ongoing CME effects,
then again on 21-Apr due to a possible weak CME impact.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
19 Apr Normal Normal-fair Fair-poor
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
20 Apr Normal Fair Poor
21 Apr Normal Normal-fair Fair
22 Apr Normal Normal Normal-fair
COMMENT: HF radio communication conditions on UT day 19-Apr were
somewhat degraded, especially in high latitudes and during local
dawn hours. Conditions in low latitudes were generally normal.
HF radio communication conditions are expected to be degraded
on 20-Apr, especially at high latitudes. Degradations are expected
to ease over 21-22 Apr.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
19 Apr 132
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Southern Australian Region:
Mostly near predicted monthly values.
Depressed by 25% after local dawn.
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
20 Apr 125 Near predicted monthly values to 30% depressed
21 Apr 120 Near predicted monthly values to 30% depressed
22 Apr 130 Near predicted monthly values
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 southern Australian
region on UT day 19-Apr were near predicted values to 25% depressed,
particularly near local dawn hours. MUFs in the northern Australian
region were near predicted values to 25% enhanced. Spread-F was
observed in Perth and Niue during local dawn hours, and in Hobart
during local night and dawn hours. Ionospheric scintillation
was observed at Niue between 19/1756-1038 UT.
MUFs are expected to be near predicted monthly values in
the northern Australian region over 20-22 Apr. MUFs are
expected to be near predicted monthly values to 30% depressed
in the southern Australian region over 20-21 Apr, returning to
mostly near predicted monthly values by 22-Apr. Shortwave fadeouts
are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 18 Apr
Daily Proton Fluence >1 MeV: 3.4E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.30E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.7
DSCOVR Satellite Solar Wind Day Averaged Data for 18 Apr
Speed: 372 km/sec Density: 3.2 p/cc Temp: 52100 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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