Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 101 Issued at 2200Z on 11 Apr 2013
IA. Analysis of Solar Active Regions and Activity from 10/2100Z to
11/2100Z: Solar activity has been at high levels for the past 24 hours.
The largest solar event of the period was a M6 event observed at
11/0716Z from Region 1719 (N10W00). There are currently 6 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares and a slight chance for an X-class flare on
days one, two, and three (12 Apr, 13 Apr, 14 Apr).
IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 507 km/s at
11/1243Z. Total IMF reached 7 nT at 11/0712Z. The maximum southward
component of Bz reached -4 nT at 11/0916Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 114 pfu at 11/1645Z.
Protons greater than 100 MeV at geosynchronous orbit reached a peak
level of 2 pfu at 11/1400Z. Electrons greater than 2 MeV at
geosynchronous orbit reached a peak level of 385 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (12 Apr), quiet to major storm levels
on day two (13 Apr) and unsettled to major storm levels on day three (14
Apr). Protons are expected to cross threshold on day one (12 Apr), have
a chance of crossing threshold on day two (13 Apr) and have a slight
chance of crossing threshold on day three (14 Apr).
III. Event probabilities 12 Apr-14 Apr
Class M 50/50/50
Class X 15/15/15
Proton 99/30/10
PCAF red
CME Update: A bright full-halo Coronal Mass Ejection (CME) is visible within the new Lasco imagery. It appears that a bulk of the plasma is directed towards the east, however there also appears to be a fair sized Earth directed
A moderately strong
solar flare was observed around Sunspot 1719 at 07:16 UTC. A Coronal
Mass Ejection (CME) was generated and looks to be directed mostly to the
east. There is however an Earth directed component that could deliver
at least a glancing blow or more to our geomagnetic field within 48
hours. Energetic Proton Levels streaming past Earth are on the rise
following the flare event. A minor to moderate S2 Level Radiation Storm
is currently in progress.
A couple more solar flares of the smaller variety were observed
following the initial M6.5 event. A minor flare measuring C4.2 was
detected around 1721 in the southeast quadrant at 10:13 UTC. Departed
Sunspot 1713 off the west limb produced a flare measuring C6.2 at 10:46
UTC. SolarSoft has the flare at C6.3.
