latest Report of Solar and Geophysical Activity 18 Aug 2012

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 231 Issued at 2200Z on 18 Aug 2012

IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity was high. Region 1548 (N19E86) produced
an M5/Sf flare at 18/0102Z, accompanied by a Tenflare (150 pfu). An
M1/Sn flare from the same region followed at 18/0323Z, also
accompanied by a Tenflare (120 pfu). Finally, an M2/1N occurred at
18/1607Z. Several coronal mass ejections (CMEs) were observed in
the past 24 hours, none appear to have a geoeffective component.
SDO 304 imagery showed a filament eruption in the vicinity of Region
1543 (N23W74) around 17/16Z. A CME was subsequently observed in
LASCO C2 coronagraph imagery at 17/1836Z, and in LASCO C3 imagery at
17/1918Z. A second filament eruption and CME was observed near
Region 1543 between 17/22Z and 18/0034Z. It was visible in STEREO-B
COR2 imagery at 18/0110Z and in LASCO C3 imagery at 18/0454Z. This
CME was directed well north of the ecliptic.

IB. Solar Activity Forecast: Solar activity is expected to be low
with moderate activity likely for the next three days (19-21
August).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was quiet to active. Solar wind speed at the
ACE spacecraft ranged between about 350-420 km/s during the period.
The Bz component of the interplanetary magnetic field ranged between
-8 and +12 nT. Solar wind density at ACE increased sharply after
18/19Z. The geomagnetic field reached active levels during the last
period (18-21Z) coincident with a change to the positive sector and
the arrival of the corotating active region.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled for the next three days (19-21
August) as a corotating interaction region and coronal hole high
speed stream become geoeffective.

III. Event Probabilities 19 Aug-21 Aug
Class M 55/55/55
Class X 05/05/05
Proton 01/01/01
PCAF Green