Weekly Highlights of Solar and Geomagnetic Activity, 04 - 10 March 2013

Weekly Highlights of Solar and Geomagnetic Activity, 04 - 10 March 2013

Post by SWPC.Webmas.. » Tue, 12 Mar 2013 20:30:09

:Product: Weekly Highlights and Forecasts
:Issued: 2013 Mar 11 0413 UTC
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#                Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
04 - 10 March 2013

Solar activity ranged from very low to moderate levels. A majority
of the week was dominated by very low levels with only B-class
events observed on 04, 06 and 08 - 10 March. Activity increased to
moderate levels on 05 March when Region 1686 (S13, L=263, class/area
Dac/140 on 06 March) produced an impulsive M1/Sf flare at 05/0754
UTC. Associated with this event were weak, low frequency radio
emissions including a Type II signature with an estimated shock
velocity of 1011 km/s. Later on 05 March, this region produced a C1
event at 2044 UTC as well as another C1 event at 08/1644 UTC as it
rotated off the visible disk. The other spotted regions on the disk
were quiet and stable through the period. No Earth-directed CMEs
were detected during the week.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels 04 - 08 March, reaching a peak flux of 7905 pfu at
06/1925 UTC. Flux levels decayed to moderate levels on 09 - 10
March.

Geomagnetic field activity was at predominately quiet levels with an
isolated unsettled period observed at 05/0000 - 0300 UTC. Solar wind
speed, as measured at the ACE spacecraft, ranged from a high of
about 500 km/s early on 04 March and exhibited a slow, steady decay
in speed through the week, ending the period near 340 km/s. Total
field measurements ranged from 1 nT to 9 nT while interplanetary
magnetic field Bz ranged between +/- 5 nT. The Phi angle began the
period in a mostly negative (towards) orientation through about
06/0800 UTC. Through the remainder of the period, field orientation
was variable, shifting from negative to positive (away).

Forecast of Solar and Geomagnetic Activity
11 March - 06 April 2013

Solar activity is likely to be low through the period. A slight
chance for M-class activity exists through 16 March while Region
1689 remains on the disk, and again from 21 March - 03 April with
the return of old Region 1686 (S12, L=263).

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at normal to moderate levels through 28 March.
Moderate to high levels are possible from 29 March - 04 April with
the return of a recurrent coronal hole high speed stream (CH HSS).
Normal to moderate levels are expected for the remainder of the
period.

Geomagnetic field activity is expected to be predominately quiet to
unsettled. Active periods are possible on 28 March due to CH HSS
effects.