Joint USAF/NOAA Report of Solar and Geophysical Activity 31 July 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Jul 31 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 212 Issued at 2200Z on 31 Jul 2011
IA. Analysis of Solar Active Regions and Activity from 30/2100Z
to 31/2100Z: Solar activity was low during the past 24 hours.
Region 1261 (N16E05) produced a C3/SN at 31/0254Z. This region has
grown in area and magnetic complexity, and classified as a
Beta-Gamma-Delta type spot group. Region 1260 (N19W22) and Region
1263 (N18E34) remained relatively unchanged.
IB. Solar Activity Forecast: Solar activity is expected to be
predominately low, with a chance for an M-class x-ray event from
Region 1260 and Region 1261 for the next three days (August 01-03).
IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z:
The geomagnetic field has been quiet to unsettled during the past 24
hours. Data observed at the ACE spacecraft indicated the
continuation of a coronal hole high speed stream, with wind
velocities reaching 690 km/s.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with a chance for isolated active
periods on day one (August 01) due to the effects from the coronal
hole high speed stream. Quiet to unsettled conditions are expected
on days two and three (02-03 August) as the effects of the coronal
hole high speed stream wane.
III. Event Probabilities 01 Aug-03 Aug
Class M 45/45/45
Class X 05/05/05
Proton 05/05/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 31 Jul 119
Predicted 01 Aug-03 Aug 120/120/120
90 Day Mean 31 Jul 095
V. Geomagnetic A Indices
Observed Afr/Ap 30 Jul 010/016
Estimated Afr/Ap 31 Jul 009/016
Predicted Afr/Ap 01 Aug-03 Aug 012/012-007/007-005/005
VI. Geomagnetic Activity Probabilities 01 Aug-03 Aug
A. Middle Latitudes
Active 35/15/05
Minor storm 15/05/01
Major-severe storm 05/01/01
B. High Latitudes
Active 40/20/05
Minor storm 20/10/01
Major-severe storm 10/01/01