[Ips-dsgr] ASWFC Daily Report - 17 April 23 issued 2330 UT on 17 Apr 2023 [SEC=OFFICIAL]

Regional Warning Centre rwc at ips.gov.au
Tue Apr 18 09:30:10 EST 2023


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 APRIL AND FORECAST FOR 18 APRIL - 20 APRIL
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 Apr:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Apr: 167/121


1B. SOLAR FORECAST
             18 Apr             19 Apr             20 Apr
Activity     R0-R1              R0-R1              R0-R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   170/124            168/122            168/122

COMMENT: Solar activity on UT day 17-Apr was at the R0 level, 
with several C-class flares. There are currently eight numbered 
sunspot regions visible on the solar disk and one unnumbered 
region. AR3282 (N11E14, beta) is the largest sunspot region and 
has shown growth in its leader spot over the UT day. AR3283 (S19E42, 
beta) has exhibited minor growth in its main spot. AR3280 (S08W77, 
beta) will soon rotate over the western limb. An unnumbered region 
recently rotated over the eastern limb at S08E81 (alpha) and 
appears to be growing. All other sunspot regions are either stable 
or in decay. The background level of X-ray flux remains at C-class 
levels. Solar activity is expected to be at R0-R1 levels over 
18-20 Apr. Several CMEs were observed, but none are considered 
geoeffective. A filament eruption was observed, visible in H-alpha 
imagery at ~N20W02 from 17/0408UT. However, no associated CME 
has been observed in the available coronagraph imagery. The solar 
wind speed on UT day 17-Apr increased, ranging from 325 to 480 
km/s, and is currently near 480 km/s. The peak total interplanetary 
field strength (IMF, Bt) was 10 nT and the north-south IMF component 
(Bz) range was +8 to -8 nT. The solar wind speed is expected 
to remain elevated over 18-20 Apr.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 17 Apr: G0

Estimated Indices 17 Apr : A   K           
   Australian Region       4   12211201
      Cocos Island         2   12210100
      Darwin               4   21211201
      Townsville           5   22212201
      Learmonth            4   22212200
      Alice Springs        3   11211201
      Gingin               3   12211200
      Canberra             3   11211201
      Hobart               3   11211201    

Estimated Antarctic Regional K Indices 17 Apr :
      Macquarie Island     1   00011200
      Casey               11   34421201
      Mawson               8   22212204

Observed Regional daily pc3 Indices 17 Apr : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             2   (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 17 Apr : A 
           Fredericksburg         5
           Planetary              5                         

Observed AFr/Ap Indices 16 Apr :  A   K
           Fredericksburg         4
           Planetary              5   1122 1122     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
18 Apr     8    G0
19 Apr    16    G0, chance G1
20 Apr    12    G0

COMMENT: ASWFC Geomagnetic Warning 18 was issued on 17 April 
and is current for 19-21 Apr. G0 geomagnetic conditions were 
observed in the Australian and Antarctic regions on 17-Apr. G0 
geomagnetic conditions are expected over 18-20 Apr, with a chance 
of G1 on 19-Apr due to weak glancing blow(s) from recent CME 
activity.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
17 Apr      Normal         Normal         Normal         

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
18 Apr      Normal         Normal         Normal-fair
19 Apr      Normal         Normal-fair    Fair
20 Apr      Normal         Normal         Normal-fair

COMMENT: Normal HF propagation conditions were observed on 17-Apr. 
Mostly normal HF propagation conditions are expected over 18-20 
Apr. Mild degradations are possible for middle to high latitudes 
on 19-Apr. Isolated shortwave fadeouts are possible.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
17 Apr   119

Observed Australian Regional MUFs
   Cocos Island Region:
      Enhanced by 25% during local day.
      Enhanced by 100% during local night.
      Enhanced by 20% after local dawn.
   Niue Island Region:
      Enhanced by 20% during local day.
      Enhanced by 20-30% during local night and after local dawn.
   Northern Australian Region:
      Mostly near predicted monthly values.
   Southern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 20-25% during local night and after local dawn.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Enhanced by 20% 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
18 Apr   115    15-20% above predicted monthly values
19 Apr   115    15-20% above predicted monthly values
20 Apr   115    15-20% above predicted monthly values

COMMENT: ASWFC SWF HF Communications Warning 37 was issued on 
16 April and is current for 17-19 Apr. Maximum usable frequencies 
(MUFs) on UT day 17-Apr in the Australian region were enhanced 
by 15-25%. Strong enhancements were observed at Cocos Island. 
Spread F was observed during local night hours at Hobart. MUFs 
are expected to be 15-20% enhanced over 18-20 Apr. Isolated shortwave 
fadeouts are possible. Mildly degraded conditions are possible 
during local night hours on 19-Apr for southern Australian regions 
due to possible arrival of a weak CME component.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 16 Apr
       Daily Proton Fluence >1 MeV:   3.3E+04
       Daily Proton Fluence >10 MeV:  2.3E+04
       Daily Electron Fluence >2 MeV: 1.30E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: C1.2

DSCOVR Satellite Solar Wind Day Averaged Data for 16 Apr
Speed: 335 km/sec  Density:    2.0 p/cc  Temp:    42700 K  Bz:   0 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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