Report of Solar-Geophysical Activity

Issued: 2012 Aug 19 2200 UTC
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Weather Prediction Center and the U.S. Air Force.

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 232 Issued at 2200Z on 19 Aug 2012

IA.  Analysis of Solar Active Regions and Activity from  18/2100Z
to 19/2100Z:  Solar activity was moderate.  Region 1548 (N19E62)
produced two M-class flares, an M1/Sf at 18/2254Z and an M1/Sn flare
at 18/2322Z.  Activity then decreased to low levels for the
remainder of the period.  Region 1548 decreased in area and ended
the period as a Cso type group with beta magnetic characteristics. 
New Region 1549 (S16W30) was numbered today and also a simple
Cso-beta type group.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
with a chance for an M-class event for the next three days (20-22
August).
IIA.  Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field ranged from quiet to unsettled levels.  A
coronal hole high speed stream became geoeffective during the past
24 hours.  At approximately 18/08Z, solar wind speed at the ACE
spacecraft began increasing from about 400 km/s to 580 km/s. 
Shortly after, the Bz component of the interplanetary magnetic field
(IMF) became negative, eventually reaching -12nT.  Bz returned to
positive values around 14Z.  Earth is currently in the positive
sector of the IMF.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at mostly unsettled levels with a chance for active
conditions on day 1 (20 August), decreasing to a slight chance on
days 2-3 (21-22 August).  The disturbed conditions are expected in
response to the continued presence of the coronal hole high speed
stream.
III.  Event Probabilities 20 Aug-22 Aug
Class M    20/20/20
Class X    01/01/01
Proton     01/01/01
PCAF       Green
IV.  Penticton 10.7 cm Flux
Observed           19 Aug 096
Predicted   20 Aug-22 Aug  100/100/105
90 Day Mean        19 Aug 125
V.  Geomagnetic A Indices
Observed Afr/Ap 18 Aug  011/013
Estimated Afr/Ap 19 Aug  010/013
Predicted Afr/Ap 20 Aug-22 Aug  012/012-007/008-007/008
VI.  Geomagnetic Activity Probabilities 20 Aug-22 Aug
A.  Middle Latitudes
Active                20/10/10
Minor storm           05/05/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/15/15
Minor storm           30/20/20
Major-severe storm    25/15/20