Joint USAF/NOAA Report of Solar and Geophysical Activity 19 April 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Apr 19 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 109 Issued at 2200Z on 19 Apr 2011
IA. Analysis of Solar Active Regions and Activity from 18/2100Z
to 19/2100Z: Solar activity has been at low levels for the past 24
hours. New Region 1195 (S16E68) rotated onto the visible disk, early
in the period, as a Dao sunspot group. Before being numbered, Region
1195 produced several C-class events off the east limb, as well as
the largest event of the past 24 hours, a C1 flare at 18/0512Z.
Region 1193 (N17W08) continues to evolve and has grown into a
beta-gamma magnetic classification.
IB. Solar Activity Forecast: Solar activity is expected to be at
low levels with a slight chance for M-class activity for the next
three days (20-22 April).
IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field has been at quiet levels for the past 24 hours.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels with a chance for
isolated active periods for the next three days (20-22 April).
Heightened activity levels are expected due to the arrival, early on
day 1, of a coronal hole high-speed stream (CH HSS). Effects from
the CH HSS are expected to last about 2 days. Late on day 2, a
slow-moving CME is expected to become geoeffective with effects
lasting through day 3.
III. Event Probabilities 20 Apr-22 Apr
Class M 15/15/15
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 19 Apr 111
Predicted 20 Apr-22 Apr 110/110/110
90 Day Mean 19 Apr 104
V. Geomagnetic A Indices
Observed Afr/Ap 18 Apr 008/010
Estimated Afr/Ap 19 Apr 005/005
Predicted Afr/Ap 20 Apr-22 Apr 010/010-010/010-010/010
VI. Geomagnetic Activity Probabilities 20 Apr-22 Apr
A. Middle Latitudes
Active 35/25/25
Minor storm 10/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 30/30/30
Minor storm 15/10/10
Major-severe storm 05/01/01