Joint USAF/NOAA Report of Solar and Geophysical Activity 12 April 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Apr 12 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 102 Issued at 2200Z on 12 Apr 2011
IA. Analysis of Solar Active Regions and Activity from 11/2100Z
to 12/2100Z: Solar activity was low. Region 1190 (N15E12) produced
three C-class flares during the period. The largest was a C3 event
at 12/0607Z. Region 1190 increased in area from 40 millionths to
approximately 70 millionths. New Regions 1191 (N09E73) and 1192
(N10E03) were numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be low.
C-class flares are likely for the next three days (13 – 15 April).
IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field was at quiet to minor storm levels. Two periods
of K=5 were observed at high latitudes during the period. The
increase was in response to a coronal hole high-speed stream. Solar
wind speeds measured at the ACE Spacecraft increased from
approximately 550 km/s to approximately 650 km/s during the past 24
hours.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at mostly quiet levels for the next three days (13 –
15 April) as the coronal hole high-speed stream effects decrease.
III. Event Probabilities 13 Apr-15 Apr
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 12 Apr 110
Predicted 13 Apr-15 Apr 110/110/110
90 Day Mean 12 Apr 101
V. Geomagnetic A Indices
Observed Afr/Ap 11 Apr 005/009
Estimated Afr/Ap 12 Apr 015/015
Predicted Afr/Ap 13 Apr-15 Apr 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 13 Apr-15 Apr
A. Middle Latitudes
Active 20/10/10
Minor storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 25/15/15
Minor storm 01/01/01
Major-severe storm 01/01/01