Joint USAF/NOAA Report of Solar and Geophysical Activity 26 April 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Apr 26 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 116 Issued at 2200Z on 26 Apr 2011
IA. Analysis of Solar Active Regions and Activity from 25/2100Z
to 26/2100Z: Solar activity has been at been at very low levels for
the past 24 hours. Region 1195 (S17W25) has started to decay , with
a decrease in both sunspot number and areal coverage. Two new
Regions were numbered today, Region 1199 (N21W23) and Region 1200
(S17E42). Region 1199 emerged quickly on the disk and is already
classified as a C-type group.
IB. Solar Activity Forecast: Solar activity is expected to be at
very low to low levels for the next three days (27-29 April).
IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z:
The geomagnetic field has been at quiet levels for the past 24 hours.
Solar wind speed, as measured by the ACE spacecraft, has continued
to decrease from around 450 – 400 km/s.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at mostly quiet levels for the next three days (27-29
April).
III. Event Probabilities 27 Apr-29 Apr
Class M 10/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 26 Apr 109
Predicted 27 Apr-29 Apr 105/105/105
90 Day Mean 26 Apr 106
V. Geomagnetic A Indices
Observed Afr/Ap 25 Apr 002/006
Estimated Afr/Ap 26 Apr 003/003
Predicted Afr/Ap 27 Apr-29 Apr 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 27 Apr-29 Apr
A. Middle Latitudes
Active 10/05/10
Minor storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/05/10
Minor storm 01/01/01
Major-severe storm 01/01/01