[Ips-dsgr] ASWFC Daily Report - 24 April 23 issued 2331 UT on 24 Apr 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Tue Apr 25 09:31:28 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/24 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 24 APRIL AND FORECAST FOR 25 APRIL - 27 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 24 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Apr: 134/88
1B. SOLAR FORECAST
25 Apr 26 Apr 27 Apr
Activity R0, chance R1 R0, chance R1 R0, chance R1
Fadeouts Possible Possible Possible
10.7cm/SSN 135/89 130/84 125/78
COMMENT: Solar activity on UT day 24-Apr was at the R0 level,
with several low level C-class flares. There are currently six
numbered sunspots regions visible on the solar disk and one unnumbered
region. AR3282 (N11W75, beta) was responsible for two low level
C-class flares is currently rotating over the western limb. Newly
numbered regions AR3286 (S11E43, alpha) and AR3287 (S25E67, alpha)
are both stable and unremarkable. An unnumbered region recently
appeared at S23E42 (beta) and has shown rapid growth since appearing
on the solar disk. All other sunspot regions are either stable
or in decay. Solar activity is expected to be at R0 levels over
25-27 Apr, with a chance of R1. A filament eruption was observed,
visible in H-alpha imagery at 24/1309UT from ~S48W10. This filament
erupted in association with a C2.8 flare from AR3283 at 24/1305UT.
A subsequent CME was observed in LASCO C2 and STEREO-A coronagraph
imagery, visible from 24/1423UT. Modelling indicates this CME
contains an Earth-directed component and a glancing impact to
Earth's magnetosphere is possible on 27-Apr at 0800UT (+/- 12
hours). No other Earth-directed CMEs have been observed. The
solar wind speed on UT day 24-Apr decreased, ranging from 485
to 660 km/s, and is currently near 525 km/s. The peak total interplanetary
field strength (IMF, Bt) was 34 nT and the north-south IMF component
(Bz) range was +24 to -33 nT. A sustained period of strong southward
IMF conditions was observed from 24/0047UT to 24/0920UT. An equatorial
coronal hole is currently crossing the central meridian and is
expected to increase the solar wind speed late on 26-Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 24 Apr: G3
Estimated Indices 24 Apr : A K
Australian Region 26 55453223
Cocos Island 18 45333223
Darwin 24 55443223
Townsville 29 55553223
Learmonth 26 55453223
Alice Springs 29 55553223
Gingin 31 56454222
Canberra 38 55664213
Hobart 42 47764213
Estimated Antarctic Regional K Indices 24 Apr :
Macquarie Island 64 66775312
Casey 47 55455723
Mawson 42 76443324
Observed Regional daily pc3 Indices 24 Apr :
Darwin 6 (Quiet)
Townsville 12 (Quiet)
Learmonth 27 (Quiet to unsettled)
Alice Springs 18 (Quiet)
Gingin 58 (Unsettled)
Canberra 69 (Active)
Hobart 107 (Major storm)
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 24 Apr : A
Fredericksburg 43
Planetary 79
Observed AFr/Ap Indices 23 Apr : A K
Fredericksburg 32
Planetary 82 2224 5597
2B. MAGNETIC FORECAST
Date Ap Conditions
25 Apr 16 G0, slight chance G1
26 Apr 8 G0
27 Apr 20 G0-G1
COMMENT: ASWFC Geomagnetic Warning 20 was issued on 24 April
and is current for 24-25 Apr. G4 planetary geomagnetic conditions
were observed on UT day 24-Apr due to ongoing CME effects from
an impact at 23/1700UT. Mostly G2 geomagnetic conditions were
observed in the Australian region, with a period of G3 observed
at Hobart. G3 geomagnetic conditions were observed in the Antarctic
region. G0 geomagnetic conditions are expected over 25-26 Apr,
with a slight chance of G1 on 25-Apr. G0-G1 geomagnetic conditions
are expected on 27-Apr due to the combined effects of a possible
glancing impact from a CME first observed on 24-Apr and coronal
hole high speed wind stream effects from an equatorial coronal
hole.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
24 Apr Normal Fair-poor Fair-poor
PCA Event : 10MeV Proton/PCA Event Began at 1800UT 23/04, Ended at 1900UT 23/04
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
25 Apr Normal Normal-fair Fair
26 Apr Normal Normal Normal-fair
27 Apr Normal Normal-fair Fair
COMMENT: Fair to poor HF propagation conditions were observed
at middle to high latitudes on 24-Apr due to increased geomagnetic
activity. Mostly normal HF propagation conditions are expected
over 25-27 Apr, with normal-fair conditions expected for middle
to high latitudes on 27-Apr due to a possible glancing impact
from a CME first observed on 24-Apr. Mild degradations are possible
during local night hours.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
24 Apr 109
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 15% during local day.
Enhanced by 90% during local night.
Enhanced by 35% after local dawn.
Northern Australian Region:
Enhanced by 20% during local day.
Enhanced by 20-35% during local night and after local dawn.
Southern Australian Region:
Depressed by 40% during local day.
Near predicted monthly values during local night.
Enhanced by 20% after local dawn.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Depressed by 35% over the UT day.
Monthly T index:
Month T index
Mar 132
Apr 84
May 84
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
25 Apr 115 Near to 15% above predicted monthly values
26 Apr 115 Near to 15% above predicted monthly values
27 Apr 115 Near to 15% above predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) on UT day 24-Apr in
the Australian region were enhanced by 20-35% in Northern Australia
and depressed by 40% in southern Australia due to recent increased
geomagnetic activity. Sporadic-E was observed at Learmonth. Strong
spread F was observed at Hobart and Perth during local night
hours. MUFs are expected to be near predicted monthly values
to 15% enhanced over 25-27 Apr. Mild degradations are possible
during local night hours.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 23 Apr
Daily Proton Fluence >1 MeV: 2.0E+08
Daily Proton Fluence >10 MeV: 1.9E+05
Daily Electron Fluence >2 MeV: 1.50E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.1
DSCOVR Satellite Solar Wind Day Averaged Data for 23 Apr
Speed: 366 km/sec Density: 3.9 p/cc Temp: 32100 K Bz: -5 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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