[Ips-dsgr] ASWFC Daily Report - 26 April 23 issued 2331 UT on 26 Apr 2023 [SEC=OFFICIAL]

Regional Warning Centre rwc at ips.gov.au
Thu Apr 27 09:31:19 EST 2023


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 APRIL 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 26 APRIL AND FORECAST FOR 27 APRIL - 29 APRIL
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 26 Apr:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Apr: 137/91


1B. SOLAR FORECAST
             27 Apr             28 Apr             29 Apr
Activity     R0, chance R1      R0, chance R1      R0, chance R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   135/89             135/89             135/89

COMMENT: Solar activity on UT day 26-Apr was at the R0 level. 
There are currently 3 numbered sunspot regions on the solar disk. 
Regions AR3285 (S19E06, beta) and AR3287 (S25E39, alpha) have 
shown some growth over the 24 hour period. A new region has rotated 
onto the disk near N20E58 but is yet to be classified. All other 
sunspot regions are either stable or in decay. Solar activity 
is expected to be at predominantly R0 levels over 27-29 Apr, 
with a chance of R1. A faint CME was observed from the SW quadrant 
following a filament eruption on 25/1933UT, but is not expected 
to be geoeffective. Several filament eruptions were observed 
on 26-Apr: in the southwest from 0537UT, in the northeast from 
0625UT and in the northwest from 0937UT. CMEs were observed following 
all of these filament eruptions, but none are considered geoeffective. 
No other CMEs were observed. The solar wind speed on UT day 26-Apr 
was on a general inclining trend and ranged between 504 to 701 
km/s, and is currently near 650 km/s. The peak total interplanetary 
field strength (IMF, Bt) was 10 nT and the north-south IMF component 
range was +8 to -7 nT. The solar wind speed is expected to be 
elevated over 27-28 due to an equatorial coronal hole high speed 
wind stream, with further enhancements from an anticipated impact 
from a CME on 27-Apr. Solar wind speeds may begin to decline 
on 29-Apr.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 26 Apr: G1

Estimated Indices 26 Apr : A   K           
   Australian Region      12   22234332
      Cocos Island         8   22123321
      Darwin              11   22234322
      Townsville          12   22234332
      Learmonth           16   22245332
      Alice Springs       12   21234332
      Gingin              15   22235332
      Canberra             9   12233322
      Hobart              11   22234322    

Estimated Antarctic Regional K Indices 26 Apr :
      Macquarie Island    26   23356432
      Casey               15   33334332
      Mawson              27   34543453

Observed Regional daily pc3 Indices 26 Apr : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        2   (Quiet)
      Gingin              22   (Quiet to unsettled)
      Canberra            29   (Quiet to unsettled)
      Hobart              44   (Unsettled)

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 26 Apr : A 
           Fredericksburg        11
           Planetary             13                         

Observed AFr/Ap Indices 25 Apr :  A   K
           Fredericksburg         7
           Planetary              8   2011 2233     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
27 Apr    20    G0-G1
28 Apr    14    G0-G1
29 Apr    10    G0

COMMENT: Mostly G0 geomagnetic conditions were observed in the 
Australian region on UT day 26-Apr, with isolated periods of 
G1 observed at Learmonth and Gingin. Mostly G0-G1 geomagnetic 
conditions were observed in the Antarctic region, with a period 
of G2 observed at Macquarie Island. G0-G1 geomagnetic conditions 
are expected over 27-28 Apr due to the combination of an equatorial 
coronal hole high speed wind steam and anticipated CME impact. 
Mostly G0 geomagnetic conditions are expected on 29-Apr.

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

PCA Event : No event.

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

COMMENT: Mildly degraded HF propagation conditions were observed 
in the Australian region on 26-Apr, primarily due to sporadic-E 
at most sites. Mildly degraded HF propagation conditions are 
expected over 27-28 Apr due to anticipated geomagnetic activity, 
with normal conditions expected by 29-Apr.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
26 Apr    99

Observed Australian Regional MUFs
   Cocos Island Region:
      Enhanced by 50% during local day.
      Enhanced by 20% during local night.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Enhanced by 20% during local day.
      Near predicted monthly values during local night.
   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
Mar      132
Apr      84
May      84

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
27 Apr    90    Near predicted monthly values to 15% depressed
28 Apr    85    Near predicted monthly values to 15% depressed
29 Apr    85    Near predicted monthly values

COMMENT: Maximum usable frequencies (MUFs) on UT day 26-Apr in 
the Australian region were enhanced by 20% in the northern region 
in local day time, and near predicted monthly values otherwise. 
Sporadic-E was observed at most sites during local night hours. 
Spread F was observed at Hobart. MUFs are expected to be near 
predicted monthly values to 15% depressed over 27-28 Apr due 
to anticipated geomagnetic activity. MUFs are expected to be 
near predicted values on 29-Apr.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 25 Apr
       Daily Proton Fluence >1 MeV:   1.1E+06
       Daily Proton Fluence >10 MeV:  2.2E+04
       Daily Electron Fluence >2 MeV: 1.30E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B6.1

DSCOVR Satellite Solar Wind Day Averaged Data for 25 Apr
Speed: 527 km/sec  Density:    9.2 p/cc  Temp:   385000 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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