[Ips-dsgr] SWS Daily Report - 25 April 17 issued 2330 UT on 25 Apr 2017 [SEC=UNCLASSIFIED]

Regional Warning Centre rwc at sws.bom.gov.au
Wed Apr 26 09:30:20 EST 2017


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 APRIL 2017 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 25 APRIL AND FORECAST FOR 26 APRIL - 28 APRIL
STATUS INDICATORS SOL:GREEN   MAG:GREEN     ION: GREEN
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 25 Apr:  Very low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Apr:  81/22


1B. SOLAR FORECAST
             26 Apr             27 Apr             28 Apr
Activity     Very low to low    Very low to low    Very low to low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    81/22              81/22              82/23

COMMENT: Solar activity was very low for the UT day, 25 April, 
with only B-class flares. The strongest was B7.2 flare occurring 
at 25/2025 UT. Very low levels of solar activity is expected 
for the next 3 UT days (26-29 April) with chance of C-class flares. 
Our model runs for the 24 April CME that was triggered by an 
eruptive filament indicate that this CME could cause a weak glancing 
blow at earth on 28 April or thereabout. No earthward directed 
CMEs were observed on UT day 25 April. The solar wind speed continued 
to decline towards nominal level over the last 24 hours, decreasing 
from 650 km/s at the beginning of the UT day to 550 km/s by the 
end of UT day, as the effect of the coronal hole slowly fades 
away. The IMF Bt was steady near 5 nT during the UT day. The 
Bz component varied between -4 nT and +4 nT. The two day outlook 
(26-27 April) is for the solar winds to continue to trend towards 
nominal levels as the effect of the coronal hole wanes.

-----------------------------------------------------------
2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 25 Apr: Quiet to Unsettled

Estimated Indices 25 Apr : A   K           
   Australian Region       8   22233221
      Cocos Island         6   11223121
      Darwin               8   12233221
      Learmonth           13   22235321
      Alice Springs        8   12233221
      Norfolk Island       6   22232111
      Culgoora             8   22233221
      Gingin              12   22234332
      Camden               9   22333221
      Canberra             7   11233220
      Launceston          11   22334221
      Hobart               9   22333221    

Estimated Antarctic Regional K Indices 25 Apr :
      Macquarie Island    25   22465331
      Casey               16   34433232
      Mawson              41   65433555

Observed Regional daily pc3 Indices 25 Apr : 
      Darwin               0   (Quiet)
      Townsville           8   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin              35   (Quiet to unsettled)
      Canberra            26   (Quiet to unsettled)
      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 25 Apr : A 
           Fredericksburg        15
           Planetary             16                         

Observed AFr/Ap Indices 24 Apr :  A   K
           Fredericksburg        19
           Planetary             22   4444 3343     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
26 Apr    15    Unsettled to Active
27 Apr    12    Unsettled
28 Apr     8    Quiet to Unsettled

COMMENT: Magnetic conditions were from quiet to unsettled levels 
across the Australian region during the UT day, 25 April. Active 
conditions were experienced in the Antarctic regions. The Earth 
is still under the influence of moderately high solar wind speed 
from a recurrent,negative polarity coronal hole, which is causing 
these moderately disturbed magnetic conditions. Mostly quiet 
to unsettled conditions are expected for the UT days 26-27 April 
as the coronal hole effects wane. Isolated active conditions 
are possible on 26 April.

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

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         Normal-fair
28 Apr      Normal         Normal         Normal-fair

COMMENT: MUFs were mostly near monthly predicted values in the 
low latitude regions on the UT day 25 April. Mild depressions 
occurred over the mid and high latitude regions. Similar MUF 
conditions are expected for today, 26 April.

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


Date   T index
25 Apr    10

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

Monthly T index:
Month  T index
Mar      11
Apr      14
May      14

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
26 Apr    10    Near predicted monthly values
27 Apr    10    Near predicted monthly values
28 Apr    15    Near predicted monthly values

COMMENT: For the UT day, 25 April, MUFs were enhanced over the 
equatorial and low latitude regions. Mild depressions occurred 
over the mid-latitude and southern Australian regions. The outlook 
for the next two days (26 and 27 April) is for similar MUF gradients. 
The southern and mid-latitude degradations of MUFs are due to 
the storm induced ionospheric depression, extending from the 
polar into the mid-latitude regions. MUFs to expect recover to 
mostly near monthly predicted level by 28 April

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

GOES satellite data for 24 Apr
       Daily Proton Fluence >1 MeV:   6.1E+07
       Daily Proton Fluence >10 MeV:  1.5E+04
       Daily Electron Fluence >2 MeV: 1.20E+09   (very high fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:32%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B1.0

ACE Satellite Solar Wind Day Averaged Data for 24 Apr
Speed: 690 km/sec  Density:    7.0 p/cc  Temp:   659000 K  Bz:  -1 nT

(Courtesy Space Weather Prediction Center, Boulder USA)
ACE data can be incorrect during strong proton events.
-----------------------------------------------------------

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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