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

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 May 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 141 Issued at 2200Z on 21 May 2011
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was very low. Four magnetically simple,
unipolar regions were observed on the visible disk, Region 1216
(S15E01) was the largest. New Region 1219 (N15E71) rotated on the
east limb and was numbered today.
IB. Solar Activity Forecast: Solar activity is expected to remain
very low to low. There is a slight chance of a C-class x-ray flare
during the next three days (22 May – 24 May).
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was quiet. Solar wind speed measured at the
ACE spacecraft increased to about 400 km/.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet for the next three days (22 May – 24 May).
III. Event Probabilities 22 May-24 May
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 21 May 084
Predicted 22 May-24 May 080/080/080
90 Day Mean 21 May 108
V. Geomagnetic A Indices
Observed Afr/Ap 20 May 002/003
Estimated Afr/Ap 21 May 005/005
Predicted Afr/Ap 22 May-24 May 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 22 May-24 May
A. Middle Latitudes
Active 15/15/10
Minor storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 20/30/15
Minor storm 05/05/05
Major-severe storm 01/01/01