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

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Oct 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 299 Issued at 2200Z on 26 Oct 2011
IA. Analysis of Solar Active Regions and Activity from 25/2100Z
to 26/2100Z: Solar activity was at low levels due to a single C1
x-ray event at 26/1001Z from Region 1324 (N12W38). Associated with
this event was a partial-halo CME, first observed in LASCO C2
imagery lifting off the NW limb at 26/1000Z. GOES-15 SXI imagery
first observed material movement from Region 1324 in a W-NW
direction at about 26/0800Z. Limited imagery prevented a thorough
analysis of the CME’s potential geoeffectiveness. The region
exhibited significant decay in area and spot count and was
classified as a beta magnetic configuration. Regions 1325 (N17W12)
and 1327 (S20W67) also indicated decay in both area coverage and
spot count. The remaining regions were unchanged.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a slight chance for M-class activity all three days (27 – 29
October).
IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z:
The geomagnetic field was quiet at all latitudes. Solar wind speeds
decayed through the period from near 550 km/s to about 400 km/s
while the Bz component of the interplanetary magnetic field did not
vary much beyond +/- 4 nT.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet on day one (27 October). Quiet to unsettled
conditions are expected on days two and three (28 – 29 October) as a
recurrent coronal hole high speed stream rotates into a geoeffective
position.
III. Event Probabilities 27 Oct-29 Oct
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 26 Oct 132
Predicted 27 Oct-29 Oct 130/130/130
90 Day Mean 26 Oct 124
V. Geomagnetic A Indices
Observed Afr/Ap 25 Oct 027/033
Estimated Afr/Ap 26 Oct 003/005
Predicted Afr/Ap 27 Oct-29 Oct 005/005-007/007-007/008
VI. Geomagnetic Activity Probabilities 27 Oct-29 Oct
A. Middle Latitudes
Active 05/10/10
Minor storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 10/15/20
Minor storm 05/10/10
Major-severe storm 01/01/01