[Ips-dsgr] ASWFC Daily Report - 20 April 23 issued 2330 UT on 20 Apr 2023 [SEC=OFFICIAL]

Regional Warning Centre rwc at ips.gov.au
Fri Apr 21 09:30:10 EST 2023


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 APRIL AND FORECAST FOR 21 APRIL - 23 APRIL
STATUS INDICATORS SOL:** YELLOW **   MAG:GREEN     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 Apr:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Apr: 147/101


1B. SOLAR FORECAST
             21 Apr             22 Apr             23 Apr
Activity     R0-R1              R0-R1              R0-R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   145/99             140/94             135/89

COMMENT: Solar activity on UT day 20-Apr was at R0 levels, with 
many low-level C-class flares. There are currently 4 numbered 
sunspot regions on the solar disk. All regions are either stable 
or in decay. AR3282 (N11W23, beta) is the largest region on the 
disk and did show some small growth, but overall has been stable. 
Solar activity is expected to be mostly at R0 levels over 21-23 
Apr, with a small chance for isolated R1 flares. A prominence 
eruption was observed to the north from 20/1446UT and a CME was 
observed from the region from 20/1612UT, and was analysed not 
to be geoeffective. No other CMEs were observed. The solar wind 
speed on UT day 20-Apr was mostly on a declining trend to background 
levels, and ranged from 450 to 366 km/s. The peak total interplanetary 
magnetic field strength (IMF, Bt) was 11 nT and the north-south 
IMF component (Bz) range was +10 to 0 nT. A partial halo CME 
first observed on 16-Apr may arrive on 21-Apr, increasing solar 
wind speeds, but confidence is low. A large coronal hole in the 
southern solar hemisphere may increase solar wind speeds on 22-23 
Apr, but this is low confidence due to its southern extent.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 20 Apr: G0

Estimated Indices 20 Apr : A   K           
   Australian Region       4   12211201
      Cocos Island         4   12211201
      Darwin               5   12211212
      Townsville           5   22211212
      Learmonth            5   22211211
      Alice Springs        3   11211201
      Gingin               2   01211200
      Canberra             2   11101101
      Hobart               1   01100101    

Estimated Antarctic Regional K Indices 20 Apr :
      Macquarie Island     0   00000001
      Casey                4   23210101
      Mawson               3   11100113

Observed Regional daily pc3 Indices 20 Apr : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      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 20 Apr : A 
           Fredericksburg         9
           Planetary             12                         

Observed AFr/Ap Indices 19 Apr :  A   K
           Fredericksburg         9
           Planetary             12   2114 4322     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
21 Apr    14    G0, slight chance G1
22 Apr    10    G0
23 Apr     8    G0

COMMENT: ASWFC Geomagnetic Warning 18 was issued on 17 April 
and is current for 19-21 Apr. G0 Geomagnetic condition were observed 
in the Australian and Antarctic regions on UT day 21-Apr. Mostly 
G0 geomagnetic conditions are expected over 21-23 Apr. There 
is a slight chance for an isolated period of G1 geomagnetic conditions 
on 21-Apr due to a glancing impact from a CME first observed 
on 16-Apr, however confidence is low.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
20 Apr      Fair-normal    Fair-normal    Fair-normal    

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
21 Apr      Normal         Normal-fair    Fair-normal
22 Apr      Normal         Normal-fair    Fair-normal
23 Apr      Normal         Normal-fair    Normal-fair

COMMENT: Mostly normal HF propagation conditions were observed 
on 20-Apr, with some degradations observed during local night 
hours. Mostly normal HF propagation conditions are expected over 
21-23 Apr, with further mild degradations possible over 21-22 
Apr.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
20 Apr   125

Observed Australian Regional MUFs
   Cocos Island Region:
      Enhanced by 15% during local day.
      Enhanced by 50% during local night.
   Niue Island Region:
      Enhanced by 50% during local day.
      Enhanced by 50% during local night.
      Enhanced by 20% after local dawn.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 30% during local night.
   Southern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 25% during local night.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Near predicted monthly values 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
21 Apr   120    15-30% above predicted monthly values
22 Apr   115    Near predicted monthly values to 15% enhanced
23 Apr   120    15-30% above predicted monthly values

COMMENT: Maximum usable frequencies (MUFs) on UT day 20-Apr in 
the Australian region were enhanced by 15-30%. Sporadic-E was 
observed at Canberra and Brisbane. Spread F was observed at Hobart. 
Scintillation was observed at Niue from 0724-0840UT. MUFs are 
expected to be 15-25% enhanced over 21-23 Apr, possibly tending 
towards monthly predicted values on 22-Apr due to a low chance 
of geomagnetic activity on 21-Apr.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 19 Apr
       Daily Proton Fluence >1 MeV:   6.2E+04
       Daily Proton Fluence >10 MeV:  2.2E+04
       Daily Electron Fluence >2 MeV: 1.40E+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 19 Apr
Speed: 487 km/sec  Density:    7.8 p/cc  Temp:   169000 K  Bz:   2 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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