[Ips-dsgr] ASWFC Daily Report - 26 April 24 issued 2330 UT on 26 Apr 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sat Apr 27 09:30:48 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 APRIL 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 26 APRIL AND FORECAST FOR 27 APRIL - 29 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 26 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Apr: 153/108
1B. SOLAR FORECAST
27 Apr 28 Apr 29 Apr
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 145/99 135/89 130/84
COMMENT: Solar activity on UT day 26-Apr was R0. The complex
cluster of sunspots in the solar southwestern quadrant has rotated
off disk. There are currently eleven numbered sunspot regions
on the solar disk, with all regions relatively minor and either
stable or in decay. A small 8 degree long solar filament erupted
from 26/1849UT visible in GONG H-alpha imagery. Solar activity
is expected to be R0-R1 over 27-29 Apr. No significantly Earth
directed CMEs were observed on 26-Apr. A sequence of northwest
CMEs were observed during the interval 26/11-20UT and a southeast
CME was observed from 26/2000UT. The northwest CME activity appears
correlated with plasma motion on or just behind the northwest
limb. The southeast CME is correlated with the small filament
eruption, with a narrow plasma spray directed southward from
S10E48 from 26/1828-2118UT visible in SDO304 imagery. Event modelling
shows an Earth miss. S0 solar radiation storm conditions were
observed on 26-Apr. S0 solar radiation storm conditions are expected
over 27-29 Apr. The solar wind environment on UT day 26-Apr became
mildly enhanced following a possible indistinct weak partial
shock like signature at 26/0023UT. There was no total magnetic
field enhancement at the time of the plasma discontinuity, though
the total field did subsequently gradually increase. The solar
wind speed ranged between 282 to 387 km/s and is currently near
322 km/sec. The peak total interplanetary field strength (IMF,
Bt) was 14 nT and the north-south IMF component range (Bz) was
+4 to -12 nT. The IMF Bz was orientated predominately mildly
southward from 26/0218UT. The solar wind speed is expected to
be mildly enhanced over 27-28 Apr due to a small equatorial coronal
hole. Another isolated coronal hole is visible in the solar southwest
quadrant centered at S35W20. This coronal hole may cause a mild
increase in solar wind speed from 29-Apr, though its more southern
latitude location may reduce effects. A long thin coronal hole
is visible to the east of the solar central meridian in the northeast
solar quadrant extending in solar latitude from N50 to S10.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 26 Apr: G0
Estimated Indices 26 Apr : A K
Australian Region 11 12324322
Cocos Island 9 22313330
Darwin 9 22223322
Townsville 11 23323322
Learmonth 14 22324432
Alice Springs 9 12323322
Gingin 12 12324332
Canberra 11 12324322
Kennaook Cape Grim 10 12324321
Hobart 10 12324321
Estimated Antarctic Regional K Indices 26 Apr :
Macquarie Island 23 12436521
Casey 10 23323321
Mawson 33 45433464
Observed Regional daily pc3 Indices 26 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (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 26 Apr : A
Fredericksburg 13
Planetary 18
Observed AFr/Ap Indices 25 Apr : A K
Fredericksburg 3
Planetary 2 1000 1011
2B. MAGNETIC FORECAST
Date Ap Conditions
27 Apr 12 G0, slight chance G1
28 Apr 10 G0, slight chance G1
29 Apr 6 G0
COMMENT: ASWFC Geomagnetic Warning 17 was issued on 26 April
and is current for 26-27 Apr. G0 geomagnetic conditions were
observed in the Australian region on UT day 26-Apr. In the Antarctic
region periods of G1 and G2 conditions were observed at Macquarie
Island and at Mawson. G0 conditions were observed at Casey. Mostly
G0 geomagnetic conditions are expected over 27-29 Apr, with a
slight chance for G1 conditions during 27-28 Apr in association
with a coronal hole high speed wind stream. There is a slight
possibility that components of recent CMEs may arrive at the
Earth, although this is not expected to induce significant activity.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 Apr Normal-fair Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 Apr Normal Normal Normal-fair
28 Apr Normal Normal Normal-fair
29 Apr Normal Normal Normal
COMMENT: HF radio communication conditions were generally fair
to normal on 26-Apr, with equatorial ionospheric scintillation
observed during local night hours. Spread F was observed at some
high latitude locations during local night hours. HF radio communication
conditions are expected to be mostly normal over 27-29 Apr, with
ongoing mildly degraded conditions at high latitudes.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 Apr 152
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 20% during local day.
Enhanced by 90% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 35% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Enhanced by 50% after local dawn.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Mar 120
Apr 114
May 115
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
27 Apr 140 About 15% above predicted monthly values
28 Apr 140 About 15% above predicted monthly values
29 Apr 140 About 15% above predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region were near predicted monthly values to 50% enhanced on
UT day 26-Apr. Strong enhancements were observed at Cocos Island
during local night hours. Ionospheric scintillation was observed
26/0731-1328UT at Niue and Weipa. Spread F was observed at Hobart
and Niue during local night hours. MUFs are expected to be near
predicted values over to 15% enhanced during the interval 27-29
Apr.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 Apr
Daily Proton Fluence >1 MeV: 2.0E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 7.20E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 9%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 25 Apr
Speed: 325 km/sec Density: 1.1 p/cc Temp: 48900 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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