[Ips-dsgr] ASWFC Daily Report - 18 May 23 issued 2331 UT on 18 May 2023 [SEC=OFFICIAL]

Regional Warning Centre rwc at ips.gov.au
Fri May 19 09:31:24 EST 2023


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 MAY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 MAY AND FORECAST FOR 19 MAY - 21 MAY
STATUS INDICATORS SOL:** YELLOW **   MAG:GREEN     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 18 May:  R1

Flares    Max     Fadeout    Freq.  Sectors
  M1.0    0626UT  possible   lower  Mid East/Indian
  M1.2    0655UT  possible   lower  Mid East/Indian
  M2.2    1147UT  possible   lower  European
  M1.1    1751UT  possible   lower  South American/
                                    Atlantic
  M3.8    2023UT  possible   lower  East Pacific/
                                    North American
  M4.5    2105UT  possible   lower  East Pacific/
                                    North American

Observed 10.7 cm flux/Equivalent Sunspot Number for 18 May: 151/106


1B. SOLAR FORECAST
             19 May             20 May             21 May
Activity     R1, chance of R2   R1, chance of R2   R1, chance of R2
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   145/99             140/94             140/94

COMMENT: Solar activity on UT day 18-May was at the R1 level 
with five M-class flares observed. An M1 flare at 18/0626UT, 
an M1.2 flare at 18/0655UT, a multipeak M2.2 flare at 18/1147UT, 
an M1.1 flare at 18/1751UT and a multipeak M4.5 flare at 18/2105UT. 
All of the M-class flares of the day were produced by newly numbered 
AR3311 (N18E74, beta). There are currently eight numbered sunspot 
regions on the solar disk. AR3305 (N08W41, beta-gamma-delta), 
AR3307 (S09W07, beta) and AR3308 (N11W27, beta) all displayed 
spot development over 18-May. Newly arrived region AR3311 is 
the most significant active region on the solar disk due to a 
history of M-class flares of increasing magnitude. AR3310 (S20E58, 
beta), which produced an M9.6 flare on 16-May appears stable 
and has produced no flares above the C-class level since then. 
Solar activity is expected to be at the R1 level over 19-21 May, 
with a chance of R2. Several CMEs were observed on 19-May, but 
none are considered geoeffective. Three west directed CMEs were 
observed in LASCO and STEREO-A imagery. A narrow CME from 18/0336UT 
associated with an eruption on the west limb at around N24 observed 
from 18/0308UT in SDO, H-Alpha and GOES SUVI imagery, no STEREO-A 
imagery is available for this CME an it is considered not geoeffective. 
The second is a faint partial halo directed broadly to the west 
visible from 18/0812UT. No on disk activity is associated with 
this event and modelling suggests it is a far side event with 
no geoeffective component. Lastly a southwest directed CME is 
visible from 18/1709UT, no on disk activity is associated with 
this event. Modelling suggests this CME will pass ahead of the 
Earth with no geoeffective component. Two filament lift offs 
were observed in SDO, GOES SUVI and H-Alpha imagery over the 
UT day. One from 18/0238UT at around S70E10 to S70W50 although 
it may continue over the limb. The other from 18/1628UT in the 
north east quadrant from around N20E30 to N35E50. No associated 
CMEs are visible in coronagraph imagery from either of these 
events. A CME observed on 17-May has been further analysed to 
have the chance of a glancing impact with Earth on 21-May. A 
slight enhancement in the 10 MeV proton flux is currently underway 
as a result of an M9.6 flare from 16-May, this is not expected 
to breach the S1 threshold. The solar wind speed decreased slightly 
over 18-May, ranging from 403 to 501 km/s and is currently at 
around 470 km/s. The peak total interplanetary field strength 
(IMF, Bt) was 4 nT and the north-south IMF component (Bz) range 
was 4 to -3 nT. The solar wind speed is expected to remain steady 
over 19-20 May. An increase is expected on 21-May due to a pair 
of coronal holes in the southern hemisphere which are rotating 
towards a geoeffective position. In addition, there is a chance 
of a glancing impact on 21-May from a CME first observed on 17-May.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 18 May: G0

Estimated Indices 18 May : A   K           
   Australian Region       0   11000000
      Cocos Island         1   11010000
      Darwin               1   11100001
      Townsville           2   11100012
      Learmonth            -   --------
      Alice Springs        0   00000000
      Gingin               0   10000000
      Canberra             0   01000000
      Hobart               0   01000000    

Estimated Antarctic Regional K Indices 18 May :
      Macquarie Island     0   00000000
      Casey                2   22100000
      Mawson               3   32200000

Observed Regional daily pc3 Indices 18 May : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth           NA
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             0   (Quiet)
      Hobart               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 18 May : A 
           Fredericksburg         4
           Planetary              4                         

Observed AFr/Ap Indices 17 May :  A   K
           Fredericksburg         5
           Planetary              4   1100 1121     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
19 May     5    G0
20 May     5    G0
21 May    15    G0, chance of G1

COMMENT: G0 geomagnetic conditions were observed in both the 
Australian and Antarctic regions on UT day 18-May. G0 geomagnetic 
conditions are expected over 19-20 May. G0 geomagnetic conditions 
with a chance of G1 are expected on 21-May due to the combined 
effects of coronal hole high speed wind streams and a possible 
glancing impact from a CME first observed on 17-May.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
18 May      Normal         Normal         Normal         

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
19 May      Normal         Normal         Normal
20 May      Normal         Normal         Normal
21 May      Normal         Normal         Normal-fair

COMMENT: Mostly normal HF propagation conditions were observed 
on 18-May. Normal HF propagation conditions are expected over 
19-21 May. Shortwave fadeouts are possible.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
18 May    89

Observed Australian Regional MUFs
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 30% during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Near predicted monthly values over the UT day.

Monthly T index:
Month  T index
Apr      120
May      87
Jun      88

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
19 May    90    Near predicted monthly values
20 May    95    Near predicted monthly values
21 May    95    Near predicted monthly values

COMMENT: ASWFC SWF HF Communications Warning 46 was issued on 
18 May and is current for 18-20 May. Maximum usable frequencies 
(MUFs) on UT day 18-May were near predicted monthly values in 
the Australian region. Spread-F was observed at Darwin and Hobart 
during local night hours. Small amounts of sporadic E were observed 
across the Australian region. MUFs are expected to be near predicted 
monthly values over 19-21 May. Shortwave fadeouts are possible.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 17 May
       Daily Proton Fluence >1 MeV:   1.7E+05
       Daily Proton Fluence >10 MeV:  4.3E+04
       Daily Electron Fluence >2 MeV: 2.70E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: C1.0

DSCOVR Satellite Solar Wind Day Averaged Data for 17 May
Speed: 430 km/sec  Density:    4.0 p/cc  Temp:   133000 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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