[Ips-dsgr] ASWFC Daily Report - 25 April 23 issued 2330 UT on 25 Apr 2023 [SEC=OFFICIAL]

Regional Warning Centre rwc at ips.gov.au
Wed Apr 26 09:30:11 EST 2023


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 25 APRIL AND FORECAST FOR 26 APRIL - 28 APRIL
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 25 Apr:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Apr: 131/85


1B. SOLAR FORECAST
             26 Apr             27 Apr             28 Apr
Activity     R0                 R0, chance of R1   R0, chance of R1
Fadeouts     None expected      Possible           Possible
10.7cm/SSN   130/84             130/84             130/84

COMMENT: Solar activity on UT day 25-Apr was at the R0 level. 
There are currently four numbered sunspots regions visible on 
the solar disk and one unnumbered region. AR3288 (S23E27, beta) 
has recently appeared on the solar disk and displayed development 
over the UT day. An unnumbered region appeared on 25-Apr at around 
N15E10 with beta magnetic characteristics. All other sunspot 
regions are either stable or in decay. Solar activity is expected 
to be at the R0 level over 26-28 Apr, with a chance of R1 on 
27-28 Apr. No Earth directed CMEs were observed. A NE directed 
CME was observed from 25/1012UT in LASCO C2 and STEREO-A imagery. 
No associated on disk activity was observed and this is considered 
a far-side event. Two filament liftoffs were visible over the 
UT day. One at around W50N50 from 25/0521UT, visible in GOES 
SUVI, SDO and H-alpha imagery. No associated CME is visible following 
this liftoff. A second liftoff was observed at around W20S40 
from 25/1933UT in GOES SUVI, SDO and H-alpha imagery. No associated 
CME is visible in currently available coronagraph imagery. Further 
analysis will be performed when more imagery is available. The 
solar wind speed was elevated over 25-Apr, with an increase over 
the first two hours of the UT day. The wind speed ranged from 
472 to 575 km/s and is currently at around 520 km/s. The peak 
total interplanetary field strength (IMF, Bt) was 9 nT and the 
north-south IMF component (Bz) range was +8 to -5 nT. The solar 
wind speed is expected to increase on 26-Apr and remain elevated 
over 27-28 Apr due to high speed wind stream effects from an 
equatorial coronal hole rotating into a geoeffective position.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 25 Apr: G0

Estimated Indices 25 Apr : A   K           
   Australian Region       7   21113232
      Cocos Island         5   11112231
      Darwin               7   21113232
      Townsville           8   21123232
      Learmonth            9   31213232
      Alice Springs        7   20113232
      Gingin               6   20103232
      Canberra             6   20113222
      Hobart               6   11113231    

Estimated Antarctic Regional K Indices 25 Apr :
      Macquarie Island     7   20004232
      Casey               13   33323242
      Mawson              21   21222356

Observed Regional daily pc3 Indices 25 Apr : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             4   (Quiet)
      Hobart              11   (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 25 Apr : A 
           Fredericksburg         7
           Planetary              9                         

Observed AFr/Ap Indices 24 Apr :  A   K
           Fredericksburg        39
           Planetary             72   7876 3334     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
26 Apr    15    G0, chance of G1
27 Apr    20    G0-G1
28 Apr    12    G0, chance of G1

COMMENT: G0 geomagnetic conditions were observed in the Australian 
region. Mostly G0 conditions were observed in the Antarctic region, 
with periods of G1 and G2 at Mawson. G0 geomagnetic conditions, 
with a chance of G1 are expected on 26-Apr due to coronal hole 
high speed wind stream effects. G0-G1 conditions are expected 
on 27-Apr due to a combination of ongoing high speed wind stream 
effects and an anticipated glancing CME impact at around 27/0800UT 
+/- 12 hours. G0 conditions, with a chance of G1 are expected 
on 28-Apr.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
25 Apr      Normal-fair    Normal         Normal         

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
26 Apr      Normal         Normal         Normal-fair
27 Apr      Normal         Normal-fair    Fair
28 Apr      Normal         Normal         Normal-fair

COMMENT: Mostly normal HF propagation conditions were observed 
in the Southern Hemisphere over 24-Apr. Mostly poor HF propagation 
conditions were observed in the Northern Hemisphere over 24-Apr. 
Mostly normal HF propagation conditions are expected over 26-28 
Apr, with degradations possible over 27-28 Apr due to geomagnetic 
activity.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
25 Apr   103

Observed Australian Regional MUFs
   Cocos Island Region:
      Enhanced by 30% during local day.
      Enhanced by 70% during local night.
   Niue Island Region:
      Enhanced by 20% during local day.
      Enhanced by 45% during local night.
   Northern Australian Region:
      Enhanced by 25% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Depressed by 15% 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
26 Apr   110    Near to 15% above predicted monthly values
27 Apr   100    Near to 15% above predicted monthly values
28 Apr    90    Near predicted monthly values

COMMENT: Maximum usable frequencies (MUFs) on UT day 25-Apr in 
the Australian region were enhanced by up to 25% in the Northern 
Australian region and 20% in the Southern Australian region during 
local day. Sporadic E was observed at Learmonth during local 
night. Spread F was observed at Hobart during local night. MUFs 
are expected to be near predicted monthly values to 15% enhanced 
over 26-28 Apr. Mild depressions are possible over 27-28 Apr 
due to geomagnetic activity.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 24 Apr
       Daily Proton Fluence >1 MeV:   1.4E+07
       Daily Proton Fluence >10 MeV:  2.6E+04
       Daily Electron Fluence >2 MeV: 9.40E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B5.4

DSCOVR Satellite Solar Wind Day Averaged Data for 24 Apr
Speed: 528 km/sec  Density:    8.8 p/cc  Temp:   344000 K  Bz:   5 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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