[Ips-dsgr] SWS Daily Report - 20 May 17 issued 2330 UT on 20 May 2017 [SEC=UNCLASSIFIED]
Regional Warning Centre
rwc at ips.gov.au
Sun May 21 09:30:23 EST 2017
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 MAY 2017 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 20 MAY AND FORECAST FOR 21 MAY - 23 MAY
STATUS INDICATORS SOL:GREEN MAG:** RED ** ION: GREEN
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1A. SOLAR SUMMARY
Activity 20 May: Very low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 May: 72/8
1B. SOLAR FORECAST
21 May 22 May 23 May
Activity Very low Very low Very low
Fadeouts None expected None expected None expected
10.7cm/SSN 72/8 74/11 74/11
COMMENT: Solar activity was very low today (UT day 20 May). As
anticipated, the effect of the negative polarity coronal hole
kept the solar wind stream strong. The solar wind speed stayed
between ~600 km/s and ~650 km/s by 09 UT and then showed a rapid
rise to over 700 km/s. The solar wind speed rose to around 750
km/s and then gradually decreased to ~650 km/s by 23 UT. The
north-south component of IMF (Bz) fluctuated mostly between +5/-11nT
during this day. Solar wind stream is expected to stay strong
for the next two to three days due to the effect of this coronal
hole. Very low levels of solar activity with some possibility
of isolated C-class event may be expected for the next three
days (21 to 23 May). ACE EPAM data indicates an energetic ion
enhancement event beginning 20/0540UT, which can be a precursor
to increased geomagnetic activity over next 24-36 hours.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 May: Mostly quiet
to minor storm
Estimated Indices 20 May : A K
Australian Region 17 23453322
Cocos Island 11 22333322
Darwin 13 22442322
Townsville 17 23453322
Alice Springs 17 23453322
Culgoora 17 23453322
Gingin 21 33453432
Camden 21 23463322
Canberra 16 23452322
Launceston 30 24564433
Hobart 23 23463422
Estimated Antarctic Regional K Indices 20 May :
Macquarie Island 51 34675632
Casey 24 33333643
Mawson 64 55656665
Observed Regional daily pc3 Indices 20 May :
Darwin 0 (Quiet)
Townsville 4 (Quiet)
Learmonth 11 (Quiet)
Alice Springs 6 (Quiet)
Gingin 87 (Minor storm)
Canberra 77 (Active)
Melbourne NA
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 20 May : A
Fredericksburg 20
Planetary 26
Observed AFr/Ap Indices 19 May : A K
Fredericksburg 13
Planetary 11 2321 3333
2B. MAGNETIC FORECAST
Date Ap Conditions
21 May 30 Active to minor storm
22 May 20 Unsettled to active, isolated minor storm periods
possible
23 May 15 Quiet to unsettled, isolated active periods possible
COMMENT: SWS Geomagnetic Warning 26 was issued on 19 May and
is current for 19-21 May. As anticipated, due to the effect of
the high speed solar wind stream from a recurrent negative polarity
coronal hole, the geomagnetic activity increased up to minor
storm levels today (UT day 20 May) with isolated major storm
periods recorded on some high latitude locations. The effect
of this coronal hole is expected to keep geomagnetic activity
enhanced for the next 2 to 3 days. Geomagnetic activity may stay
high at active to minor storm levels on 21 May, and at unsettled
to active levels with some possibility of isolated minor storm
periods on 22 May. Geomagnetic activity is expected to decline
to quiet to unsettled levels on 23 May with some possibility
of isolated active periods on this day.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 May Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 May Normal-fair Fair Fair-poor
22 May Normal Normal-fair Fair-poor
23 May Normal Normal Normal
COMMENT: Against the anticipations, despite high level of geomagnetic
activity today (UT day 20 May), minor to moderate MUF enhancements
were observed. Minor to moderate MUF depressions and degradation
in HF conditions may be expected on 21 May due to an expected
continued rise in geomagnetic activity on this day. Minor to
mild MUF depressions and degradation in HF conditions may be
expected on 22 May. HF conditions may be expected to recover
to mostly normal levels on 23 May.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 May 26
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 20% during local day.
Near predicted monthly values 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 during local day.
Enhanced by 25% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 35% during local night.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Apr 14
May 12
Jun 12
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
21 May 10 20 to 40% below predicted monthly values
22 May 15 Depressed 10 to 20%/near predicted monthly values
23 May 20 Near predicted monthly values
COMMENT: SWS Preliminary HF Communications Warning 28 was issued
on 19 May and is current for 19-21 May. Against the anticipations,
despite high level of geomagnetic activity today (UT day 20 May),
minor to moderate MUF enhancements were observed in the Aus regions.
Minor to moderate MUF depressions and degradation in HF conditions
may be expected in the Aus/NZ regions on 21 May due to an expected
continued rise in geomagnetic activity on this day. Minor to
mild MUF depressions and degradation in HF conditions may be
expected in the Aus/NZ regions on 22 May. HF conditions may be
expected to recover to mostly normal levels on 23 May.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 May
Daily Proton Fluence >1 MeV: 3.9E+07
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 6.30E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: A5.0
ACE Satellite Solar Wind Day Averaged Data for 19 May
Speed: 455 km/sec Density: 7.6 p/cc Temp: 196000 K Bz: 0 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
ACE data can be incorrect during strong proton events.
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Space Weather Services email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386 WWW: http://www.sws.bom.gov.au
Haymarket NSW 1240 AUSTRALIA FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010 fax: +61 2 9213 8060
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