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

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 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 233 Issued at 2200Z on 21 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was very low to low. Region 1271
(N16W01) produced a C2/Sf event at 20/2258Z. Region 1272 (S21E03)
produced several B-class/Sf events in the past 24 hours followed by
a C1/Sf at 21/1840Z. Regions 1271 and 1272 showed significant growth
in trailer areas. Region 1275 (N06E68) was numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a slight chance for moderate activity.
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was quiet to unsettled due to the arrival of a
favorably positioned negative polarity coronal hole.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled with a chance for active conditions at high
latitudes on Days 1 and 2 (22-23 Aug) with the arrival of a second
coronal hole high speed stream (HSS). Day 3 (24 Aug) is expected to
decrease to quiet conditions as effects from the HSS subside.
III. Event Probabilities 22 Aug-24 Aug
Class M 20/20/20
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 21 Aug 101
Predicted 22 Aug-24 Aug 103/105/105
90 Day Mean 21 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 20 Aug 004/005
Estimated Afr/Ap 21 Aug 005/005
Predicted Afr/Ap 22 Aug-24 Aug 010/012-008/010-005/005
VI. Geomagnetic Activity Probabilities 22 Aug-24 Aug
A. Middle Latitudes
Active 25/20/15
Minor storm 10/05/01
Major-severe storm 05/01/01
B. High Latitudes
Active 40/40/15
Minor storm 20/15/05
Major-severe storm 10/05/01