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

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Jul 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 199 Issued at 2200Z on 18 Jul 2011
IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity has been at low levels for the past 24
hours. Region 1254 (S22E11) produced the largest event of the
period, a C1/Sf flare at 18/1028Z. Two new regions were numbered
today: Region 1258 (N11W37) emerged on the disk and is magnetically
classified as a beta and Region 1259 (N26E69) rotated on the disk as
a Dao-beta group. Early in the period, two CME’s were observed in
LASCO C2 and C3 imagery but neither appear to be Earth directed.
IB. Solar Activity Forecast: Solar activity is expected to be at
very low to low levels for the next two days (19-20 July). Activity
is expected to decrease to very low levels on day three (21 July) as
Region 1257 (N20W69) rotates off the west limb.
IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was at quiet to unsettled levels for the past
24 hours. Measurements by the ACE spacecraft indicated a solar
sector boundary crossing (from positive to negative) at around
18/0230Z. Following the crossing, coronal hole high-speed stream
characteristics were monitored, with solar wind speeds increasing
from 370 km/s to around 460 km/s.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels on day one (19 July),
and at quiet to active levels on days two and three (20-21 July), as
another coronal hole high-speed stream becomes geoeffective.
III. Event Probabilities 19 Jul-21 Jul
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 18 Jul 102
Predicted 19 Jul-21 Jul 102/100/096
90 Day Mean 18 Jul 097
V. Geomagnetic A Indices
Observed Afr/Ap 17 Jul 003/005
Estimated Afr/Ap 18 Jul 006/008
Predicted Afr/Ap 19 Jul-21 Jul 010/010-012/012-012/012
VI. Geomagnetic Activity Probabilities 19 Jul-21 Jul
A. Middle Latitudes
Active 25/30/30
Minor storm 01/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 30/35/35
Minor storm 01/10/10
Major-severe storm 01/01/01