[Ips-dsgr] ASWFC Daily Report - 18 August 23 issued 2330 UT on 18 Aug 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sat Aug 19 09:30:47 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 AUGUST 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 AUGUST AND FORECAST FOR 19 AUGUST - 21 AUGUST
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 18 Aug: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Aug: 150/105
1B. SOLAR FORECAST
19 Aug 20 Aug 21 Aug
Activity R0,chance R1 R0,chance R1 R0,chance R1
Fadeouts Possible Possible Possible
10.7cm/SSN 150/105 152/107 155/109
COMMENT: Solar activity on UT day 18-Aug was R0. There are currently
8 numbered sunspot regions on the solar disk. Most of the solar
regions are relatively small and magnetically simple. Small solar
region AR3409(N18W40, gamma) is currently the most magnetically
complex region and produced a C3.7 flare at 18/1950UT and a C3.0
flare at 18/2135UT, associated with two minor Hyder-flares, as
two small solar filaments located at N20W42 and N18W45, visible
in GONG Big Bear H-alpha imagery, erupted in sequence. A brief
very weak solar proton enhancement may possibly follow these
minor events, as both briefly showed a small parallel ribbon
flare structure. This region appeared to be recently developing
but has now shown some decay towards the end of the UT day. All
other sunspot regions are stable or in decay. Solar region AR3380,
which produced R1 solar flares on its previous disk transit,
may return to the south east solar limb (S11) on 18-Aug. Solar
activity is expected to be R0 with the chance of an isolated
R1 flare during 19-21 Aug. No significantly Earth directed CMEs
have been observed. A narrow north west directed CME was observed
in LASCO C2 from 18/1136UT which could not be correlated with
on disk activity. LASCO imagery will be checked for any possible
CME associated with the small filament eruptions as GOES SUVI
shows narrow ejecta to the north west from 18/2140UT. The solar
wind speed on UT day 18-Aug ranged between 315 and 553 km/s.
During the interval 18/0145-18/0740UT the solar wind speed showed
three step increases, with IMF Bz increasing and fluctuating
southwards, and the total field showing an abrupt enhancement
from 18/0157UT. The solar wind density exhibited a declining
trend over the UT day. The source signature in the solar wind
is somewhat ambiguous, perhaps more indicating a coronal hole
effect rather than a weak CME, with a possible corotating interactive
region early in the UT day, with an overall decline in solar
wind density as the speed increased. The peak total interplanetary
field strength (IMF, Bt) was 15 nT and the north-south IMF component
(Bz) range was +12 nT to -12 nT. The solar wind speed is currently
around 460km/sec and is expected to be moderately elevated with
a declining trend for today.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Aug: G0
Estimated Indices 18 Aug : A K
Australian Region 8 23321122
Cocos Island 4 22220111
Darwin 6 23221112
Townsville 9 23331122
Learmonth 8 22331222
Alice Springs 9 33331112
Gingin 7 22321122
Canberra 7 23221122
Hobart 6 13221122
Estimated Antarctic Regional K Indices 18 Aug :
Macquarie Island 14 12453112
Casey 12 34332222
Mawson 17 23431235
Observed Regional daily pc3 Indices 18 Aug :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 6 (Quiet)
Hobart 19 (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 18 Aug : A
Fredericksburg 10
Planetary 11
Observed AFr/Ap Indices 17 Aug : A K
Fredericksburg 10
Planetary 7 3220 2222
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Aug 10 G0
20 Aug 8 G0
21 Aug 6 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 18-Aug. Mostly G0 geomagnetic conditions were
observed in the Antarctica region, with an isolated period of
G1 at Macquarie Island and Mawson. G0 geomagnetic conditions
are expected over 19-21 Aug.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Aug Normal Normal-fair Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Aug Normal Normal Normal-fair
20 Aug Normal Normal Normal-fair
21 Aug Normal Normal Normal
COMMENT: HF radio communication conditions on UT day 18-Aug were
mostly normal, with some mild degradations at middle to high
latitudes during local night hours. Normal conditions are generally
expected 19-21 Aug, with mild degradation at middle to high latitudes
for 19-Aug.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Aug 128
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Niue Island Region:
Enhanced by 20-40%.
Northern Australian Region:
Near predicted monthly values to 30% enhanced.
Southern Australian Region:
Enhanced by 15-20%.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Jul 103
Aug 88
Sep 84
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
19 Aug 125 Near to 20% above predicted monthly values
20 Aug 125 Near to 20% above predicted monthly values
21 Aug 125 Near to 20% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 80 was issued on
17 August and is current for 17-19 Aug. Maximum usable frequencies
(MUFs) on UT day 18-Aug were near predicted monthly values to
30% enhanced in the Australian region. Spread was observed in
Brisbane, Hobart and Canberra during local night hours. Ionospheric
amplitude scintillation (S4 index of 0.8) was briefly observed
at Niue 18/0800UT. MUFs are expected to remain near predicted
values to 20% enhanced over 19-21 Aug. Isolated fadeouts possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Aug
Daily Proton Fluence >1 MeV: 1.5E+05
Daily Proton Fluence >10 MeV: 2.0E+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: B8.0
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Aug
Speed: 328 km/sec Density: 4.8 p/cc Temp: 36900 K Bz: 1 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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