Joint USAF/NOAA Report of Solar and Geophysical Activity 23 July 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Jul 23 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 204 Issued at 2200Z on 23 Jul 2011
IA. Analysis of Solar Active Regions and Activity from 22/2100Z
to 23/2100Z: Solar activity was very low. Region 1254 (S26W54) and
Region 1259 (N23E02) are classified as Cao type spot groups. Both
regions remained quiet and stable. Multiple B class x-ray events
were observed, the largest a B5 at 23/1449 Z. The origin of the
activity is just beyond the east limb and is likely returning Region
1246 (L=329).
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low for the next three days (24-26 July).
IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field has been quiet to unsettled during the past 24
hours. Solar wind data observed at the ACE spacecraft indicated a
decrease in velocity from 600 km/s to about 500 km/s during the
period. The greater than 2 MeV electron flux at geosynchronous orbit
reached high levels during the period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with a slight chance of isolated
active periods for the next three days (24-26 July). The activity is
forecast due to the expected arrival of another coronal hole high
speed stream.
III. Event Probabilities 24 Jul-26 Jul
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 23 Jul 088
Predicted 24 Jul-26 Jul 088/088/086
90 Day Mean 23 Jul 096
V. Geomagnetic A Indices
Observed Afr/Ap 22 Jul 010/010
Estimated Afr/Ap 23 Jul 008/008
Predicted Afr/Ap 24 Jul-26 Jul 006/006-005/005-009/009
VI. Geomagnetic Activity Probabilities 24 Jul-26 Jul
A. Middle Latitudes
Active 10/10/15
Minor storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 10/10/15
Minor storm 05/05/05
Major-severe storm 01/01/01