[Ips-dsgr] ASWFC Daily Report - 21 September 23 issued 2333 UT on 21 Sep 2023 [SEC=OFFICIAL]
rwc
rwc at ips.gov.au
Fri Sep 22 09:33:14 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 SEPTEMBER AND FORECAST FOR 22 SEPTEMBER - 24 SEPTEMBER
STATUS INDICATORS SOL:** RED ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Sep: R2
Flares Max Fadeout Freq. Sectors
M8.7 1254UT probable lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Sep: 168/122
1B. SOLAR FORECAST
22 Sep 23 Sep 24 Sep
Activity R1-R2,chance R3 R1-R2,chance R3 R1-R2,chance R3
Fadeouts Probable Probable Probable
10.7cm/SSN 162/116 162/116 165/119
COMMENT: Solar activity on UT day 21-Sep was R2, with a short
duration M8.7 flare from AR3435(N13E23, beta-gamma-delta). This
region's spot distribution has reconfigured in the past 24 hours
and a more significant delta spot is now evident in the southwest
arm of this region. Increased flare activity is now expected
from this region. Nearby AR3438(N04E12, beta-gamma), which consists
of scattered smaller spots, shows both growth and decay. A new
solar region AR3443(N22W23, beta-gamma) has emerged on disk and
has shown rapid growth and currently consists of a number of
smaller spots. The scattered small trailer spots to the south
east of AR3442(S15E52, beta-gamma) leader spot have also continued
to develop in size and number. Solar region AR3441(N01W12, beta-gamma-delta)
has also shown growth, with a very small delta spot evident in
a spot in the north of this region. There are currently eleven
numbered solar regions on the visible solar disk. Solar activity
is expected to be R1-R2 with an isolated R3 event possible over
22-24 Sep. A small solar filament erupted from the solar disk
in GONG H-alpha imagery located at N10E60 at 21/1850UT and is
not considered significant. No significantly Earth directed CMEs
has been observed, however there is a data gap in available LASCO
C2/C3 imagery from 21/1036-1436UT. The Stereo-A space based coronagraph
shows a narrow south directed (out of the ecliptic plane) CME
from 21/1323UT and from 21/1423UT a broader fainter south and
east directed CME is visible. It is possible that the earlier
narrow southward CME is associated with the M8.7 flare. Both
of these events are considered as not significantly Earth directed.
The solar wind speed on UT day 21-Sep declined, ranging from
395 to 453 km/sec and is currently near 407km/sec. The peak total
interplanetary magnetic field strength (IMF, Bt) was 6 nT and
the north-south IMF component (Bz) range was 4 to -4 nT. A small
equatorial coronal hole located at solar longitude W30 may increase
solar wind speeds slightly during 22-23-Sep. Another small coronal
hole is located at N40W10.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 Sep: G0
Estimated Indices 21 Sep : A K
Australian Region 9 22313312
Cocos Island 7 12312312
Darwin 8 22313212
Townsville 8 22313222
Learmonth 10 22313323
Alice Springs 9 22313312
Gingin 10 22303323
Canberra 7 11303312
Hobart 8 12303312
Estimated Antarctic Regional K Indices 21 Sep :
Macquarie Island 9 12224311
Casey 10 33322222
Mawson 23 25322445
Observed Regional daily pc3 Indices 21 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 4 (Quiet)
Canberra 0 (Quiet)
Hobart 14 (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 Sep : A
Fredericksburg 8
Planetary 9
Observed AFr/Ap Indices 20 Sep : A K
Fredericksburg 15
Planetary 20 3344 3444
2B. MAGNETIC FORECAST
Date Ap Conditions
22 Sep 14 G0, slight chance of G1 later in UT day
23 Sep 16 G0, slight chance of G1
24 Sep 12 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 21-Sep. In the Antarctic region isolated periods
of G1 were observed at Mawson. G0 geomagnetic conditions are
generally expected on 22-24 Sep, with a wind stream from a small
coronal possibly inducing a mild increase in geomagnetic activity
over 22-23 Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 Sep Normal Normal-fair Fair
23 Sep Normal Normal-fair Fair
24 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 21-Sep were
normal. Mildly degraded conditions are possible during local
night hours on 22-23 Sep for middle to high latitudes. Shortwave
fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 Sep 105
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Niue Island Region:
Enhanced by 20-35%.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Southern Australian Region:
Depressed 15% during local day.
Near predicted monthly values during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 115
Sep 96
Oct 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
22 Sep 95 Near predicted monthly values
23 Sep 95 Near predicted monthly values
24 Sep 95 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 96 was issued on
20 September and is current for 20-22 Sep. Maximum usable frequencies
(MUFs) in the Australian region on UT day 21-Sep were depressed
15% during during the local day on the Australian south-east
coast, with northern Australian region MUFs near predicted values
to 25% enhanced. The south west coast remained near predicted
monthly values. Spread-F was observed at Hobart during local
night hours. MUFs are generally expected to be near predicted
monthly values over 22-24 Sep. Mild degradations may be experienced
during local night hours on 22-23 Sep due to anticipated mild
geomagnetic activity from a coronal hole wind stream. There is
a chance for further brief mild depressions after local dawn
on 23-24 Sep in the southern Australian region. Shortwave fadeouts
probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 Sep
Daily Proton Fluence >1 MeV: 1.2E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 7.10E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 9%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B9.4
DSCOVR Satellite Solar Wind Day Averaged Data for 20 Sep
Speed: 512 km/sec Density: 0.2 p/cc Temp: 60500 K Bz: 0 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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