[Ips-dsgr] ASWFC Daily Report - 27 December 23 issued 2330 UT on 27 Dec 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Thu Dec 28 10:30:10 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/27 DECEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 27 DECEMBER AND FORECAST FOR 28 DECEMBER - 30 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 27 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 27 Dec: 149/104
1B. SOLAR FORECAST
28 Dec 29 Dec 30 Dec
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
Fadeouts Possible Possible Possible
10.7cm/SSN 150/105 145/99 145/99
COMMENT: Solar activity on UT day 27-Dec was at the R0 level
with few low level C-class flares. There are currently five numbered
sunspot regions visible on the solar disk and one unnumbered
region. AR3529 (S20W62, beta) is the largest sunspot region on
the solar disk, however it is not magnetically complex, is stable
and has not produced any M-class flares over the last several
days. AR3526 (N15W62, beta) and AR3533 (N15W22, gamma) both showed
spot development over the UT day, but neither are particularly
complex or have a history of M-class flaring. An unnumbered region
is visible at around S12E60 with beta magnetic complexity. All
other sunspot regions are either stable or in decay. Solar activity
is expected to be at the R0 level over 28-30 Dec, with a chance
of R1. No Earth-directed CMEs have been observed. Several slow
and faint CMEs were observed on 27-Dec. A south directed partial
halo CME visible from 27/0324UT in SOHO and STEREO-A imagery,
with no associated on disk source. This CME is not considered
geoeffective. A northeast directed, very slow CME visible in
SOHO and STEREO-A imagery from 27/1712UT possibly associated
with a faint eruption visible from 27/1657UT in SDO imagery at
around N30E45. This CME is not considered geoeffective. A southwest
directed CME visible from 27/1824UT in SOHO and STEREO-A imagery.
This CME has no on disk source associated with it and modelling
indicates it is not geoeffective. A filament lift off behind
the northeast limb is visible from 27/1916UT in SDO and GOES
SUVI imagery. No associated CME is visible in available coronagraph
imagery. The location of the eruption suggests that any CME from
this event is unlikely to be geoeffective. The solar wind speed
on UT day 27-Dec declined slightly, ranging from 510 to 419 km/s
and is currently near 445 km/s. The peak total interplanetary
field strength (IMF, Bt) was 7 nT and the north south IMF component
(Bz) range was +5 to -4 nT. The solar wind speed is expected
to be elevated on 28-Dec due to multiple forecast impacts from
CMEs first observed on 24-Dec. The solar wind speed is then expected
to decline gradually over 29-30 Dec towards background levels.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 27 Dec: G0
Estimated Indices 27 Dec : A K
Australian Region 4 22121111
Cocos Island 3 21111110
Darwin 4 21211112
Townsville 4 21221111
Learmonth 5 22122112
Alice Springs 4 22121101
Gingin 5 31121102
Canberra 3 12111101
Hobart 4 12221101
Estimated Antarctic Regional K Indices 27 Dec :
Macquarie Island 2 12110000
Casey 21 46333113
Mawson 11 44222212
Observed Regional daily pc3 Indices 27 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 2 (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 27 Dec : A
Fredericksburg 8
Planetary 10
Observed AFr/Ap Indices 26 Dec : A K
Fredericksburg 4
Planetary 4 0112 2100
2B. MAGNETIC FORECAST
Date Ap Conditions
28 Dec 15 G0-G1
29 Dec 8 G0
30 Dec 5 G0
COMMENT: ASWFC Geomagnetic Warning 81 was issued on 25 December
and is current for 27-28 Dec. G0 geomagnetic conditions were
observed in the Australian region on UT day 27-Dec. Mostly G0
geomagnetic conditions were observed in the Antarctic region,
with an isolated period of G2 at Casey. G0-G1 geomagnetic conditions
are expected on 28-Dec due to forecast impacts from CMEs first
observed on 24-Dec. G0 conditions are expected on 29-30 Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
27 Dec Normal Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
28 Dec Normal Normal Normal-fair
29 Dec Normal Normal Normal-fair
30 Dec Normal Normal Normal
COMMENT: HF radio communication conditions on UT day 27-Dec were
mostly normal for most of the UT day, with some degradations
observed at mid to high latitudes in the northern hemisphere
in the last quarter of 27-Dec. Mostly normal conditions are expected
over 28-Dec, with a chance of mild degradations at high latitudes
if geomagnetic activity eventuates. Mostly normal conditions
are expected on 29-30 Dec. Isolated minor shortwave fadeouts
are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
27 Dec 133
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Nov 114
Dec 100
Jan 98
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
28 Dec 125 Near to 15% above predicted monthly values
29 Dec 125 Near to 15% above predicted monthly values
30 Dec 125 Near to 15% above predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) on UT day 27-Dec in
the Australian region were near predicted monthly values, with
enhancements of up to 15% observed in the southern Australian
region during local night. Sporadic E obscured the foF2 at Perth
at times during local night. MUFs are expected to be near predicted
monthly values to 15% enhanced on 28-Dec, with less enhancements
to mild depressions possible in the southern Australian region
if geomagnetic activity eventuates. MUFs are expected to be near
predicted monthly values to 15% enhanced over 29-30 Dec. Isolated
shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 26 Dec
Daily Proton Fluence >1 MeV: 4.6E+05
Daily Proton Fluence >10 MeV: 2.6E+04
Daily Electron Fluence >2 MeV: 4.80E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B7.7
DSCOVR Satellite Solar Wind Day Averaged Data for 26 Dec
Speed: 474 km/sec Density: 7.2 p/cc Temp: 192000 K Bz: 2 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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