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Here is this week's space weather and geophysical report, issued 2015 Mar 16 0717 UTC.
Highlights of Solar and Geomagnetic Activity
09 - 15 March 2015
Solar activity ranged from moderate to high levels with Region 2297
(S17, L=196, class/area Dkc/420 on 13 March) responsible for all the
M-class and X-class activity. High levels were observed from 09-12
March as Region 2297 produced several greater than M5 flares during
this time period including an X2/2b flare at 11/1622 UTC with an
associated Tenflare (160 sfu), Type II (1461 km/s) and IV radio
sweeps, and a non-Earth directed coronal mass ejection (CME). Also,
on 11 March was a 22 degree long filament eruption, centered near
N16W30 that lifted off the visible disk between 11/0625-0815 UTC
that produced a partially Earth directed CME visible in SOHO/LASCO
C2 imagery at 11/0848 UTC. By 13 March through the end of the
period, solar activity declined to moderate levels as Region 2297
underwent decay. On 15 March, a sequence of events led to an Earth
directed asymmetric halo CME. The events began with a 14 degree long
filament eruption, centered near S24W38, lifting off between
15/0045-0200 UTC. This was followed by a C2/Sf flare at 15/0041 UTC
and a long duration C9/1f flare at 15/0213 UTC, both from Region
2297. Associated with the C9 flare were low-frequency radio
emissions including Type II (745 km/s) and Type IV radio sweeps.
WSA/ENLIL modelling showed an approximate arrival time around
17/2000 UTC. Altogether, Region 2297 produced 83 C-flares, 20
M-flares, and 1 X-flare during its transit to date.
A greater than 10 MeV proton enhancement was observed at
geosynchronous orbit on 15 March beginning around 15/0300 UTC and
reaching a maximum flux level of 4 pfu at 15/0940 UTC before slowly
receding to the 1 pfu level by the end of the period. The
enhancement was the result of the combination of a filament eruption
and C9 flare activity from Region 2297 early on 15 March.
The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels on 09 and 10 March reaching a maximum flux level of
1,150 pfu at 09/1840 UTC. Moderate levels were observed from 11-13
March, while normal levels were observed from 14-15 March.
Geomagnetic field activity was mostly quiet to unsettled levels
during the period. Solar wind speed was in decline at the beginning
of the period from initial values near 570 km/s. By 10 March, solar
wind speed was near 400 km/s with total field measurement between 4
and 7 nT. Solar wind conditions continued under a nominal solar wind
regime through the rest of the period with only minor enhancements
in total field measurements to 11 nT. By late on 14 March, a solar
sector boundary crossing was observed at 14/2138 UTC switching from
a mostly positive into a negative sector. By 15 March, a brief
enhancement of the total field was observed at 15/1727 UTC to 15 nT.
This enhancement was possibly a glancing blow that was expected from
the 11 March CME. The geomagnetic field was mostly quiet to
unsettled throughout with quiet conditions observed on 10 and 14
March.
Forecast of Solar and Geomagnetic Activity
16 March - 11 April 2015
Solar activity is expected to continue at moderate levels until 19
March when Region 2297 transits off the visible disk. Conditions are
expected to decrease to very low to low levels through 31 March. By
01 April and through the rest of the forecast period, the return of
Region 2297 is expected to increase activity to low levels with a
chance for M-class activity.
A chance for a greater than 10 MeV proton event exists from 16-21
March due to further potential significant flare activity from
Region 2297 as well as a possible enhancement of the proton flux
levels when the 15 March CME arrives late on 17 March.
The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels from 20-25 March, 28-31 March, and
again from 03-05 April due to recurrent coronal hole high speed
stream (CH HSS) activity.
Geomagnetic field activity is expected to be at unsettled to active
levels with minor storm periods likely on 18 March due to a
combination of CH HSS effects as well as the arrival of the 15 March
CME by mid to late on 17 March. Unsettled to active periods are also
likely from 22-24 March, 27-31 March, and 02-04 April with minor
storming possible on 28-29 March due to recurrent CH HSS activity.
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