[Ips-dsgr] ASWFC Daily Report - 16 April 24 issued 2331 UT on 16 Apr 2024 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Wed Apr 17 09:31:01 EST 2024
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/16 APRIL 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 16 APRIL AND FORECAST FOR 17 APRIL - 19 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 16 Apr: R1
Flares Max Fadeout Freq. Sectors
M1/-- 1802UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 16 Apr: 199/151
1B. SOLAR FORECAST
17 Apr 18 Apr 19 Apr
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 200/152 200/152 180/133
COMMENT: Solar activity on UT day 16-Apr was at the R1 level,
due to an impulsive M1.1 flare from AR3643(S12E48, beta). There
are currently eleven numbered sunspot regions on the solar disk,
with two new regions currently rotating onto the disk over the
northeast solar limb. Three regions AR3634(N25W56, beta), AR3639(N29E45,beta)
and AR3643 are medium sized regions. Of the other smaller regions
AR3638(S16E35, beta-gamma) is the most magnetically complex.
Solar region AR3634 has shown development in its leader spots
penumbra and trailer spots, AR3639 has shown development in its
intermediate spots and 3643 has shown slight growth with emerging
smaller surrounding spots. Smaller more magnetically complex
AR3638 has shown slight growth, with some smaller surrounding
spots emerging. All other numbered regions are either stable
or in decay. A 15 degree long solar filament located at S45E30
lifted off the solar disk in GONG H-alpha imagery from 16/1900UT.
Solar activity is expected to be at R0-R1 levels over 17-19 Apr.
Solar radiation conditions were at the S0 level and are expected
to remain at this level over 17-19 Apr. No significantly geoeffective
CMEs were observed on 16-Apr. A northeast solar limb CME was
observed from 16/0824UT. The start of a southward narrow CME
was observed in LASCO C2 from 16/2112UT, likely associated with
the filament eruption. The southward latitude of the filaments
location and initial coronagraph imagery suggest a narrow CME
directed out of the ecliptic plane. Modelling will be conducted
as further images become available. The solar wind speed was
mildly elevated and steady over the UT day 16-Apr ranging from
341 to 422 km/s. The wind speed is currently around 374 km/s.
The peak total interplanetary field strength (IMF, Bt) was 13
nT and the north-south IMF component (Bz) range was +4 to -12
nT. The solar wind IMF total field (Bt) was mildly enhanced with
IMF Bz predominately orientated mildly southward over the UT
day following a weak CME component arrival 15/1727UT. Solar wind
speed is generally expected to remain near to slightly above
background levels over 17-19 Apr. A CME observed on 14-Apr may
cause enhanced solar wind conditions due to a possible glancing
impact late on 17-Apr, this impact is not expected to be significant.
A small equatorial coronal hole is located just to the east of the
solar central meridian, centred at S10E05.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 16 Apr: G0
Estimated Indices 16 Apr : A K
Australian Region 15 32333343
Cocos Island 12 22233432
Darwin 14 32333342
Townsville 15 32333343
Learmonth 19 32333453
Alice Springs 15 32333343
Gingin 19 32333453
Canberra 14 21333343
Kennaook Cape Grim 18 31433443
Hobart 17 32433343
Estimated Antarctic Regional K Indices 16 Apr :
Macquarie Island 34 32555553
Casey 12 33332232
Mawson 29 53444345
Observed Regional daily pc3 Indices 16 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 16 Apr : A
Fredericksburg 23
Planetary 29
Observed AFr/Ap Indices 15 Apr : A K
Fredericksburg 7
Planetary 7 1201 1233
2B. MAGNETIC FORECAST
Date Ap Conditions
17 Apr 13 G0, slight chance of G1 late in UT day.
18 Apr 13 G0, slight chance of G1 early in UT day.
19 Apr 8 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 16-Apr, with a mild increase in geomagnetic
activity observed following the arrival of a weak component of
a recent CME at 15/1727UT and subsequent sustained mildly southward
orientated solar wind IMF conditions on 16-Apr. The Australian
region Dst index fell to -116 overnight and the planetary Kp-index
reached G1 for the period 16/18-21UT. In the Antarctic region
G1 periods were observed at Macquarie Island and Mawson with
G0 conditions observed at Casey. G0 geomagnetic conditions are
generally expected on 17-19 Apr, with another weak CME component
arrival possible late on 17-Apr.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
16 Apr Normal Normal-fair Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
17 Apr Normal Normal-fair Fair
18 Apr Normal Fair-normal Fair-normal
19 Apr Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 16-Apr were
mostly normal, with mildly degraded conditions at middle to high
latitudes. HF radio propagation conditions are expected to be
mostly normal over 17-19 Apr, with mildly degraded conditions
again possible for middle to high latitudes on 17-Apr. Isolated
minor shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
16 Apr 143
Observed Australian Regional MUFs
Cocos Island Region:
Mostly near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Enhanced by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Enhanced by 45% after local dawn.
Southern Australian Region:
Enhanced by 15% during local day.
Enhanced by 25% during local night.
Briefly depressed 10-15% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 30% 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
17 Apr 120 Near predicted monthly values
18 Apr 120 Near predicted monthly values
19 Apr 120 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 36 was issued on
14 April and is current for 15-17 Apr. Maximum usable frequencies
(MUFs) in the Australian region on UT day 16-Apr were generally
near predicted monthly values, with Hobart MUFs briefly depressed
10-15% after local dawn this morning. Strong predawn spread F
was observed at Hobart. MUFs are expected to be near predicted
monthly values over 17-19 Apr. Isolated minor shortwave fadeouts
are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 15 Apr
Daily Proton Fluence >1 MeV: 1.7E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 7.40E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.5
DSCOVR Satellite Solar Wind Day Averaged Data for 15 Apr
Speed: 346 km/sec Density: 1.8 p/cc Temp: 47200 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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