[Ips-dsgr] SWS Daily Report - 17 May 21 issued 2343 UT on 17 May 2021

rwc rwc at ips.gov.au
Tue May 18 09:43:53 EST 2021


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 MAY 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 17 MAY AND FORECAST FOR 18 MAY - 20 MAY
STATUS INDICATORS SOL:GREEN   MAG:** YELLOW **     ION: GREEN
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1A. SOLAR SUMMARY
Activity 17 May:  Very low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 17 May:  75/13


1B. SOLAR FORECAST
             18 May             19 May             20 May
Activity     Very low           Very low           Very low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    76/14              75/13              74/11

COMMENT: Solar activity was very low on UT day 17 May. AR2822 
(Hsx/Alpha) is now the only spotted region on the visible disk 
of the Sun and is approaching the North Western limb. However 
there is a new region just appearing on the North Eastern limb 
that is showing flare potential with a series of weak B-class 
flares. There were no significant Earth directed CMEs observed 
in the available coronagraph images up to 17/1436 UT. Solar activity 
is expected to be very low for the next three UT days 18-20 May 
with a slight chance of C-class flares. On the UT day 17 May 
the solar wind was slightly enhanced for the first half of the 
day peaking at 425 km/s, but dropped down to 330 km/s at 14 UT. 
Then there was a sudden jump in solar wind speed from 330 km/s 
to 350 km/s at 1545 UT, with a corresponding increase in density 
and the IMF component (Bz) was mostly southwards from 16-20 UT. 
This weak shock was most likely the arrival of the 13 May CME. 
The IMF (Bt) peaked at 8 nT and the north-south IMF component 
(Bz) range was +4/-8 nT. The solar wind speed is expected to 
be enhanced on UT days 18-20 May due to an equatorial coronal 
hole wind stream. The slow 14 May CME is expected to arrive on 
18 May but only weak effects are expected.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 17 May: Quiet

Estimated Indices 17 May : A   K           
   Australian Region       3   11100222
      Cocos Island         2   01100221
      Darwin               3   11101212
      Townsville           4   11110222
      Learmonth            4   11101222
      Alice Springs        3   11100122
      Gingin               4   11100232
      Canberra             2   11100121
      Hobart               3   11110122    

Estimated Antarctic Regional K Indices 17 May :
      Macquarie Island     1   00110011
      Casey                6   23211122
      Mawson              18   23312255

Observed Regional daily pc3 Indices 17 May : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             0   (Quiet)
      Melbourne           NA

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 May : A 
           Fredericksburg         8
           Planetary             12                         

Observed AFr/Ap Indices 16 May :  A   K
           Fredericksburg         4
           Planetary              5   1002 2122     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
18 May    20    Quit to Active with possible minor storm periods.
19 May    20    Quit to Active with possible minor storm periods.
20 May    12    Quit to unsettled with possible active periods.

COMMENT: SWS Geomagnetic Warning 18 was issued on 15 May and 
is current for 17-18 May. Geomagnetic conditions in the Australian 
region were mostly quiet on UT day 17 May. In the Antarctic region 
mostly quiet to unsettled levels with one minor storm period 
were observed. Global geomagnetic conditions are expected to 
be quiet to active with possible minor storm periods on UT days 
18-19 May, due to coronal hole effects plus the possible arrival 
of a weak CME that occurred on 14 May. Mostly quiet to unsettled 
geomagnetic conditions with possible active periods are expected 
on UT day 20 May.

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

PCA Event : No event.

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

COMMENT: Mostly normal HF propagation conditions are expected 
on UT days 18-20 May with some possible mild to moderate degradations.

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


Date   T index
17 May    15

Observed Australian Regional MUFs
   Cocos Island Region:
      No data available.
   Niue Island Region:
      Depressed by 15% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values 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
Apr      12
May      21
Jun      24

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
18 May    15    Near predicted monthly values
19 May     5    Near predicted monthly values/depressed 10 to 
                30%
20 May     5    Near predicted monthly values/depressed 10 to 
                30%

COMMENT: MUFs in the Australian region on UT day 17 May were 
near predicted monthly values with some mild depressions in the 
Niue Island Region occurring during the local day. There were 
also some moderate enhancements in the Southern Australian region 
during the local night. MUFs are expected to be near predicted 
monthly values on UT days 18-20 May with some possible mild to 
moderate depressions due to the expected increase in geomagnetic 
activity.

-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 16 May
       Daily Proton Fluence >1 MeV:   6.3E+04
       Daily Proton Fluence >10 MeV:  4.3E+04
       Daily Electron Fluence >2 MeV: 1.90E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: A4.1

DSCOVR Satellite Solar Wind Day Averaged Data for 16 May
Speed: 369 km/sec  Density:    3.9 p/cc  Temp:    64600 K  Bz:  -1 nT

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

Space Weather Services              email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386                         WWW: http://www.sws.bom.gov.au
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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