Report of Solar-Geophysical Activity

Issued: 2012 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 110 Issued at 2200Z on 19 Apr 2012

IA.  Analysis of Solar Active Regions and Activity from  18/2100Z
to 19/2100Z:  Solar activity was low. The largest event of the period
was a C7 x-ray flare at 19/1126Z associated with Types II and IV
radio sweeps and a non-Earth-directed CME. This event may have
originated in old Region 1455 (N05, L=206), now about two days
beyond the west limb. Regions 1460 (N16W01) and 1463 (S26W49) each
produced a low-level C-class flare. Region 1460 showed spot growth
in its intermediate portion. Region 1462 (S24W31) produced a C1
flare at 19/1515Z associated with a CME that may have had an
Earthward component. Further analysis is required to determine if
the CME is likely to be geoeffective. New Region 1464 (N23E01,
Bxo-Beta) was numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
during days 1 - 3 (20 - 22 April) with a chance for an isolated
M-class flare.
IIA.  Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field was quiet.
IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is
expected to be at quiet to unsettled levels on day 1 (20 April) with
a chance for brief active levels due to a recurrent solar sector
boundary crossing. Quiet levels are expected during days 2- 3 (21 -
22 April).
III.  Event Probabilities 20 Apr-22 Apr
Class M    30/30/30
Class X    01/01/01
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           19 Apr 138
Predicted   20 Apr-22 Apr  135/135/135
90 Day Mean        19 Apr 112
V.  Geomagnetic A Indices
Observed Afr/Ap 18 Apr  007/008
Estimated Afr/Ap 19 Apr  004/005
Predicted Afr/Ap 20 Apr-22 Apr  007/008-004/005-003/005
VI.  Geomagnetic Activity Probabilities 20 Apr-22 Apr
A.  Middle Latitudes
Active                25/10/10
Minor storm           05/01/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                35/15/15
Minor storm           15/01/01
Major-severe storm    01/01/01