Joint USAF/NOAA Report of Solar and Geophysical Activity 21 March 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Mar 21 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 080 Issued at 2200Z on 21 Mar 2011
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity increased to low levels. Isolated
C-class flares were observed, the largest of which was a
long-duration C4 at 21/1719Z from newly-numbered Region 1176
(S13E81). Region 1176 was the return of old Region 1165, which
produced M-class flares during its previous rotation. SOHO/LASCO
images showed a halo-CME, first visible in C2 images at 21/0236Z.
The halo-CME was determined to be a backside event associated with a
flare from old Region 1169 (N20, L=061).
IB. Solar Activity Forecast: Solar activity is expected to be low
during days 1 – 3 (22 – 24 March) with a chance for an M-class flare
from Region 1176.
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
Geomagnetic field activity was at quiet levels. A greater than 10 MeV
proton event at geosynchronous orbit began at 21/1950Z and was in
progress at the time of this report. Stereo-A EUVI 195 images
indicated the source for the proton event was likely a flare from
old Region 1169 which also spawned the back sided halo-CME mentioned
above.
IIB. Geophysical Activity Forecast: Geomagnetic activity is
expected to be at quiet levels during days 1 – 2 (22 – 23 March).
Geomagnetic activity is expected to increase to quiet to unsettled
levels on day 3 (24 March) as a coronal hole high-speed stream
begins to disturb the field. The greater than 10 MeV event at
geosynchronous orbit is expected to end on day 1 (March 22).
III. Event Probabilities 22 Mar-24 Mar
Class M 30/30/30
Class X 05/05/05
Proton 10/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 21 Mar 101
Predicted 22 Mar-24 Mar 115/125/135
90 Day Mean 21 Mar 094
V. Geomagnetic A Indices
Observed Afr/Ap 20 Mar 004/004
Estimated Afr/Ap 21 Mar 002/004
Predicted Afr/Ap 22 Mar-24 Mar 005/005-005/005-008/008
VI. Geomagnetic Activity Probabilities 22 Mar-24 Mar
A. Middle Latitudes
Active 10/10/15
Minor storm 01/01/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/20
Minor storm 01/01/10
Major-severe storm 01/01/01