[Ips-dsgr] ASWFC Daily Report - 16 September 23 issued 2337 UT on 16 Sep 2023 [SEC=OFFICIAL]
rwc
rwc at ips.gov.au
Sun Sep 17 09:37:44 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/16 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 16 SEPTEMBER AND FORECAST FOR 17 SEPTEMBER - 19 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 16 Sep: R1
Flares Max Fadeout Freq. Sectors
M2.9 0050UT possible lower West Pacific.
M3.4 0538UT possible lower E. Asia/Aust.
Observed 10.7 cm flux/Equivalent Sunspot Number for 16 Sep: 140/94
1B. SOLAR FORECAST
17 Sep 18 Sep 19 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 145/99 140/94 135/89
COMMENT: Solar activity on UT day 16-Sep was at the R1 level,
due to M2.9 and M3.4 flares both produced by solar region AR3429(N11W18,
beta-gamma-delta). The delta spot within this sunspot region appears
to have sheared apart in an east to west direction resulting
in the opposite polarity area within the delta spot being greatly
reduced. This region is now considered to have a much lower flare
probability. There are currently five numbered solar regions
on the visible disk. Other spot groups are stable or in decay.
Returning solar region AR3413 is currently rotating onto the
solar disk at solar latitude N10, at this stage it appears to
be a medium sized region. As the region is still rotating onto
the disk magnetic classification is not yet possible. Another
smaller region appears to be just behind the eastern solar limb
at solar latitude S22. Solar activity is now expected to be at
R0-R1 level over 17-19 Sep. A significant Earth-directed asymmetric
full halo CME was observed on 16-Sep after the eruption of a
large 30 degree long solar filament spanning from N25W00 to N10W27
and erupting during the interval 16/0400-0800UT. This broad filament
had a wispy structure which may indicate lower density/mass and
no Hyder flare was observed during the filament eruption. The
resulting halo CME was visible in LASCO C2 from 16/0912UT and
C3 16/1018UT. Event modelling shows an impact to the Earth's
magnetosphere at 18/2000UT +/- 12 hrs. A narrow far side CME
was observed off the north east solar limb from 16/0636UT. The
solar wind speed was variable on 16-Sep, ranging from 404 to
493 km/s and is currently near 405 km/s. The peak total interplanetary
field strength (IMF, Bt) was 6 nT and the north-south IMF component
(Bz) range was +5 to -5 nT. An enhancement in solar wind speed
which was expected during the interval from late 16-Sep to mid
17-Sep due to the anticipated arrival of a CME observed on 14-Sep
is now looking less likely as the ACE EPAM CME precursor channel
is only showing a slight upward trend. A small equatorial coronal
hole is visible centered at W25 and may induce a moderate increase
in solar wind speeds on 18-Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 16 Sep: G0
Estimated Indices 16 Sep : A K
Australian Region 4 11110222
Cocos Island 4 12110122
Darwin 4 22100122
Townsville 2 1111011-
Learmonth 6 22110232
Alice Springs 3 11100222
Gingin 5 21110232
Canberra 2 10000122
Hobart 4 10100232
Estimated Antarctic Regional K Indices 16 Sep :
Macquarie Island 2 00000222
Casey 11 33320233
Mawson 18 21210165
Observed Regional daily pc3 Indices 16 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 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 16 Sep : A
Fredericksburg 6
Planetary 7
Observed AFr/Ap Indices 15 Sep : A K
Fredericksburg 7
Planetary 11 2211 3433
2B. MAGNETIC FORECAST
Date Ap Conditions
17 Sep 18 G0, chance of G1
18 Sep 15 Initially G0, with G1-G2 periods late in UT day.
19 Sep 55 G2, chance of G3
COMMENT: ASWFC Geomagnetic Warning 51 was issued on 15 September
and is current for 15-17 Sep. G0 geomagnetic conditions were
observed in the Australian region on 16-Sep. Mostly G0 conditions
were observed in the Antarctic region, with isolated periods
of G1 and G2 observed at Mawson. The anticipated increase in
geomagnetic activity for 16-Sep has yet to eventuate and is now
considered less likely. There is still a chance this CME may
arrive on 17-Sep, but any induced activity is now expected to
be weaker. A CME associated with a large solar filament eruption
on 16-Sep is expected to increase geomagnetic activity to G2,
with the chance of G3 periods from late 18-Sep to 19-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
16 Sep Normal Normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
17 Sep Normal Normal-fair Fair
18 Sep Normal Normal-poor Normal-poor
19 Sep Normal Fair-poor Poor
COMMENT: HF radio propagation conditions on UT day 16-Sep were
normal. Moderately degraded HF conditions are now not expected
for middle to high latitudes on 17-Sep due. HF conditions are
expected to become moderately to strongly degraded at middle
to high latitudes from late 18-Sep to 19-Sep, due to recent CME
associated with a large solar filament eruption on 16-Sep.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
16 Sep 100
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 65% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
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
17 Sep 100 Near predicted monthly values
18 Sep 100 Near predicted monthly values
19 Sep 75 Depressed 15 to 25%/near predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 92 was issued
on 15 September and is current for 17-18 Sep. Maximum usable
frequencies (MUFs) on UT day 16-Sep were near predicted monthly
values. Minor fadeouts were observed in association with the
M2 and M3 flares on 16-Sep. MUFs are now expected to be near
predicted monthly values on 17-Sep, as anticipated geomagnetic
activity from mid 16-Sep has not eventuated. However, degraded
HF conditions are expected on 19-20 Sep due to expected geomagnetic
storm activity from a recent CME associated with an solar filament
eruption. Shortwave fadeouts are now considered less likely for
today.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 15 Sep
Daily Proton Fluence >1 MeV: 2.8E+06
Daily Proton Fluence >10 MeV: 1.9E+04
Daily Electron Fluence >2 MeV: 3.90E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.0
DSCOVR Satellite Solar Wind Day Averaged Data for 15 Sep
Speed: 459 km/sec Density: 6.7 p/cc Temp: 173000 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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