Weekly Highlights of Solar and Geomagnetic Activity, 11 - 17 March 2013

Weekly Highlights of Solar and Geomagnetic Activity, 11 - 17 March 2013

Post by SWPC.Webmas.. » Tue, 19 Mar 2013 20:30:07

:Product: Weekly Highlights and Forecasts
:Issued: 2013 Mar 18 0210 UTC
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#                Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
11 - 17 March 2013

Solar activity was low to moderate. Low activity dominated the week
with only low level C-class events observed on 11-14 and 16-17
March. A long duration C2/1f flare associated with a filament
eruption near N20E05 occurred at around 12/1107 UTC. An associated
asymmetric full halo was assessed to be Earth-directed with a
velocity in the low 700 km/s range at departure. Activity increased
to moderate levels on 15 March when Region 1692 (N09, L=077,
class/area Hhx/250 on 09 March) produced an M1/1f long duration
flare at 15/0658 UTC. This flare appeared in H-alpha imagery to
erupt along a NE to SW oriented filament channel and partially
through Region 1692 beginning at 15/0615 UTC. Associated with this
flare were a 150 sfu Tenflare, a Type IV radio sweep, and an
asymmetrical full-halo CME (estimated plane-of-sky speed of 1399
km/s). The CME first appeared in SOHO/LASCO C2 imagery at 15/0712
UTC.

A greater than 10 MeV proton event associated with the 15 March CME
began at 16/1940 UTC, reached a maximum flux of 16 pfu at 17/0700
UTC, and ended at 17/0825 UTC.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels throughout the period.

Geomagnetic field activity was quiet from 11-14 March. Activity
increased slightly to yield a few isolated unsettled periods on
15-16 March due to weak effects from the 12 March CME. The
geomagnetic field began at quiet levels on 17 March. At 17/0601 UTC,
a geomagnetic Sudden Impulse (41 nT on the Boulder magnetometer) was
observed as the 15 March CME became geoeffective. Minor to major
storm periods were subsequently observed with major to severe storm
periods at high latitudes for the 17/0900-2100 UTC periods.

Forecast of Solar and Geomagnetic Activity
18 March - 13 April 2013

Solar activity is expected to be low throughout the period. A slight
chance for M-class activity exists through 20 March while Regions
1696 (N04, L=095, class/area Eai/190 on 16 March) and 1698 (S19,
L=118, class/area Eao/200 on 17 March) remain on the disk, and again
from 01-13 April when the two regions are expected to return to the
visible disk.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to begin the period at moderate levels but rise to high
levels from 19-24 March due to effects from the 15 March CME. A
decrease to normal to moderate levels is then expected through 28
March. High levels are expected from 29 March-04 April due to
effects from a recurrent coronal hole high speed stream (CH HSS). A
return to normal to moderate levels is expected for the remainder of
the period.

Geomagnetic field activity is expected to be at quiet to minor storm
levels on 18 March due to continued effects from the 15 March CME.
Quiet to unsettled levels are expected to prevail throughout the
remainder of the period with the exception of possible active
periods on 28 March due to CH HSS effects.