[Ips-dsgr] SWS Daily Report - 24 September 21 issued 2331 UT on 24 Sep 2021

Regional Warning Centre rwc at ips.gov.au
Sat Sep 25 09:31:01 EST 2021


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/24 SEPTEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 24 SEPTEMBER AND FORECAST FOR 25 SEPTEMBER - 27 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: GREEN
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1A. SOLAR SUMMARY
Activity 24 Sep:  Low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Sep:  88/32


1B. SOLAR FORECAST
             25 Sep             26 Sep             27 Sep
Activity     Low to moderate    Low to moderate    Low to moderate
Fadeouts     Possible           Possible           Possible
10.7cm/SSN    88/32              86/29              82/23

COMMENT: Solar activity was low on UT day 24 September. Currently 
there are 5 numbered regions on the visible solar disk. AR2871 
produced a C2.9 flare at 0701 UT and could produce more M-class 
flares. There was a narrow CME towards the west in Lasco & Stereo-A 
images starting at 24/1248 UT, but a source could not be found 
on the visible disk and it is unlikely to have an Earth directed 
component. Also there was a filament eruption near E05S23 around 
24/1440 UT observed in H-alpha images. There was another filament 
eruption observed in SDO images near S30W05 around 24/1748 UT. 
No Earth-directed CMEs were observed in the available coronagraph 
data over the previous 24 hours. Solar activity is expected to 
be low to moderate on UT days 25-27 September. On UT day 24 September, 
the solar wind speed followed an increasing trend from 400 km/s 
up to 500 km/s. The total IMF (Bt) peaked at 10 nT and the north-south 
IMF (Bz) varied between 7 nT and -5 nT. For UT day 25 September, 
light to moderate solar wind speeds are expected. The solar wind 
parameters may become disturbed on UT days 26-27 September due 
to the combined effects of a northern polar coronal hole with 
extension down to low latitudes, plus a glancing blow from the 
23 September CMEs caused by two M-class flares.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 24 Sep: Quiet to Unsettled

Estimated Indices 24 Sep : A   K           
   Australian Region       5   22210301
      Cocos Island         4   12210300
      Darwin               6   22211302
      Townsville           6   22221311
      Learmonth            5   22211300
      Alice Springs        5   22210301
      Gingin               6   22210401
      Canberra             4   22210300
      Hobart               5   21210311    

Estimated Antarctic Regional K Indices 24 Sep :
      Macquarie Island     6   11201420
      Casey               17   45431311
      Mawson              13   33221334

Observed Regional daily pc3 Indices 24 Sep : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin              32   (Quiet to unsettled)
      Canberra            11   (Quiet)
      Hobart              34   (Quiet to 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 24 Sep : A 
           Fredericksburg         7
           Planetary             10                         

Observed AFr/Ap Indices 23 Sep :  A   K
           Fredericksburg        10
           Planetary              8   2242 2111     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
25 Sep    10    Quiet to Unsettled
26 Sep    20    Quiet to Active with possible isolated minor 
                storms
27 Sep    20    Quiet to Active with possible isolated minor 
                storms

COMMENT: On UT day 24 September, geomagnetic conditions in the 
Australian region were mostly quiet to unsettled. In the Antarctic 
region, quiet to active levels were observed with one minor storm 
period. Quiet to unsettled conditions are expected for UT day 
25 September. An increase in geomagnetic activity up to unsettled 
and active levels with possible isolated minor storms is expected 
on UT days 26-27 September. This disturbance is due to the combined 
effects of a northern polar coronal hole with extension down 
to low latitudes, plus a glancing blow from the 23 September 
CMEs caused by two M-class flares.

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

PCA Event : No event.

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

COMMENT: Mostly normal HF propagation conditions are expected 
on UT day 25 September. There is a chance of Short-wave fadeouts 
on UT days 25-27 September. Mildly degraded conditions are likely 
on UT days 26-27 September due to the expected increase in geomagnetic 
activity.

-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
24 Sep    31

Observed Australian Regional MUFs
   Cocos Island Region:
      Near predicted monthly values during local day.
      Enhanced by 20% during local night.
   Niue Island Region:
      No data available.
   Northern Australian Region:
      Depressed by 15% during local day.
      Enhanced by 20% during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Enhanced by 15% over the UT day.

Monthly T index:
Month  T index
Aug      14
Sep      27
Oct      30

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
25 Sep    25    Near predicted monthly values
26 Sep    20    Near predicted monthly values/depressed 10 to 
                20%
27 Sep    15    Near predicted monthly values/depressed 10 to 
                20%

COMMENT: SWS SWF HF Communications Warning 24 was issued on 23 
September and is current for 23-25 Sep. MUFs in the Australian 
region on UT day 24 September were mostly near predicted monthly 
values, with some enhancements during the local night. There 
were also some mild MUF depressions during the local day in the 
Northern Australian region. MUFs in the Australian region are 
expected to be near predicted monthly values on UT day 25 September. 
Some mild MUF depressions are possible on UT days 26-27 September 
due to the expected increase in geomagnetic activity.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 23 Sep
       Daily Proton Fluence >1 MeV:   1.3E+05
       Daily Proton Fluence >10 MeV:  4.6E+04
       Daily Electron Fluence >2 MeV: 1.60E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B1.3

DSCOVR Satellite Solar Wind Day Averaged Data for 23 Sep
Speed: 383 km/sec  Density:   10.0 p/cc  Temp:    69900 K  Bz:   1 nT

(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------

Space Weather Services              email: asfc at bom.gov.au
Bureau of Meteorology
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Haymarket NSW 1240  AUSTRALIA       FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010                fax: +61 2 9213 8060 

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