Joint USAF/NOAA Report of Solar and Geophysical Activity 4 April 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Apr 04 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 094 Issued at 2200Z on 04 Apr 2011
IA. Analysis of Solar Active Regions and Activity from 03/2100Z
to 04/2100Z: Solar activity was very low. New Region 1185 (N23E72)
was numbered today. Multiple CME’s were observed by Stereo Ahead
COR2 imagery. A long duration B-class event was associated with the
CME that lifted off of the Northeast limb at approximately 04/0509Z.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low with a slight chance for moderate activity (isolated
M-class event) from Region 1183 (N16W38) for the next three days (05
– 07 April).
IIA. Geophysical Activity Summary 03/2100Z to 04/2100Z:
The geomagnetic field was at quiet to unsettled levels. ACE solar
wind data showed wind speeds decreasing from approximately 600 km/s
to approximately 460/km/s as the coronal hole high speed stream (CH
HSS) effects wane. The greater than 2 MeV electron flux at
geosynchronous orbit was at high levels throughout the period.
IIB. Geophysical Activity Forecast: Geomagnetic field activity is
expected to be mostly quiet on days one and two (05 – 06 April).
Activity is expected to increase to quiet to unsettled levels with
isolated active periods on day three (07 April) in response to
coronal hole effects. The CME mentioned above is not expected to be
geo-effective.
III. Event Probabilities 05 Apr-07 Apr
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 04 Apr 113
Predicted 05 Apr-07 Apr 105/105/100
90 Day Mean 04 Apr 099
V. Geomagnetic A Indices
Observed Afr/Ap 03 Apr 011/016
Estimated Afr/Ap 04 Apr 008/010
Predicted Afr/Ap 05 Apr-07 Apr 005/005-005/005-008/008
VI. Geomagnetic Activity Probabilities 05 Apr-07 Apr
A. Middle Latitudes
Active 10/10/20
Minor storm 01/01/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/25
Minor storm 01/01/10
Major-severe storm 01/01/01