Joint USAF/NOAA Report of Solar and Geophysical Activity 17 August 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 17 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 229 Issued at 2200Z on 17 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 16/2100Z
to 17/2100Z: Solar activity was low. Both Regions 1271 (N16E50) and
1272 (S19E55) produced C-class events during the summary period.
The largest was a C3 from Region 1271 at 17/1119Z. Region 1271
ended the period as an Esi type spot group with beta-gamma-delta
magnetic characteristics. New Region 1273 (S18W03) was numbered
today and classified as a Bxo type spot group with simple beta
magnetic characteristics. A CME from Region 1272 was observed in
SOHO/LASCO C2 imagery at 17/0248Z with a plane-of-sky speed of about
550 km/s. This CME is not expected to be geoeffective.
IB. Solar Activity Forecast: Solar activity is expected to be low.
Continued C-class events are expected from Regions 1271 and 1272,
There is a slight chance for an M-class event given the increasing
size and complexity of Region 1271.
IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z:
The geomagnetic field was quiet to unsettled. Wind speed at the ACE
spacecraft continued to decline through the summary period, ending
near 420 km/s.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly quiet for the next three days (18-20 August).
III. Event Probabilities 18 Aug-20 Aug
Class M 15/15/15
Class X 01/05/05
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 17 Aug 098
Predicted 18 Aug-20 Aug 098/100/100
90 Day Mean 17 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 16 Aug 006/008
Estimated Afr/Ap 17 Aug 008/008
Predicted Afr/Ap 18 Aug-20 Aug 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 18 Aug-20 Aug
A. Middle Latitudes
Active 10/05/10
Minor storm 01/01/05
Major-severe storm 00/00/05
B. High Latitudes
Active 20/05/20
Minor storm 05/05/05
Major-severe storm 05/01/05