Joint USAF/NOAA Report of Solar and Geophysical Activity 10 April 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Apr 10 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 100 Issued at 2200Z on 10 Apr 2011
IA. Analysis of Solar Active Regions and Activity from 09/2100Z
to 10/2100Z: Solar activity was very low. Only B-class events were
observed. Region 1185 (N18E01) grew from an area of 30 millionths to
60 millionths. Region 1186 (N23E06) grew from 40 millionths to 70
millionths. Regions 1188 (S24W34) and 1189 (N23W16) are now plage
regions. A CME was observed on SOHO/LASCO C2 imagery on the
Northeast limb at approximately 10/0312Z.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low with a slight chance for C-class flares for the next
three days (11 – 13 April).
IIA. Geophysical Activity Summary 09/2100Z to 10/2100Z:
The geomagnetic field was at quiet levels.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels, with isolated active
levels at mid-latitudes on day one (11 April). The increase in
activity is due to a coronal hole high-speed stream. Activity is
expected to decrease to mostly quiet levels on days two and three
(12 – 13 April) as the coronal hole high-speed stream effects wane.
The CME referenced in paragraph 1A, is not expected to be
geoeffective.
III. Event Probabilities 11 Apr-13 Apr
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 10 Apr 105
Predicted 11 Apr-13 Apr 095/100/100
90 Day Mean 10 Apr 101
V. Geomagnetic A Indices
Observed Afr/Ap 09 Apr 004/010
Estimated Afr/Ap 10 Apr 005/005
Predicted Afr/Ap 11 Apr-13 Apr 010/012-005/005-005/005
VI. Geomagnetic Activity Probabilities 11 Apr-13 Apr
A. Middle Latitudes
Active 35/20/10
Minor storm 05/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 40/25/15
Minor storm 10/01/01
Major-severe storm 05/01/01