Joint USAF/NOAA Report of Solar and Geophysical Activity 18 February 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Feb 18 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 049 Issued at 2200Z on 18 Feb 2011
IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity was high during the past 24 hours.
Region 1158 (S19W64) produced several C-class events with a C1 at
17/2135Z that was associated with a Type II Sweep and an M1 event at
18/1303Z. Region 1161 (N12W02) grew slightly in area and maintained
a beta-gamma magnetic classification. New Region 1162 (N18W06) was
numbered today and developed rapidly into a Dai-type sunspot group
with a beta-gamma magnetic classification. The bulk of the activity
originated from this new region, including two M1 events and an M6
event at 18/1011Z.
IB. Solar Activity Forecast: Solar activity is expected to be
moderate with a chance for isolated high level activity for the next
three days (19-21 February).
IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was unsettled to active with an isolated minor
storm period at high latitudes. This activity was due to the
effects of the CMEs associated with two M-class events and an
X-class event observed from 13-15 February. A sudden impulse of 33
nT was observed at 18/0136Z at the Boulder magnetometer in
association with this event. The ACE spacecraft indicated solar wind
velocities increased to approximately 700 km/s along with a
sustained period of southward Bz between -10 and -15 nT from
18/0200-0300Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with a chance for isolated active
periods for day one (19 February) due to the residual effects of the
recent CMEs. Days two and three (20-21 February) are expected to be
mostly quiet.
III. Event Probabilities 19 Feb-21 Feb
Class M 75/75/75
Class X 15/15/15
Proton 10/10/10
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 18 Feb 125
Predicted 19 Feb-21 Feb 120/120/110
90 Day Mean 18 Feb 086
V. Geomagnetic A Indices
Observed Afr/Ap 17 Feb 005/002
Estimated Afr/Ap 18 Feb 018/022
Predicted Afr/Ap 19 Feb-21 Feb 010/012-005/005-005/005
VI. Geomagnetic Activity Probabilities 19 Feb-21 Feb
A. Middle Latitudes
Active 25/15/05
Minor storm 10/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 25/20/05
Minor storm 10/05/01
Major-severe storm 01/01/01