:Product: 0518RSGA.txt
:Issued: 2012 May 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 139 Issued at 2200Z on 18 May 2012
IA.  Analysis of Solar Active Regions and Activity from  17/2100Z
to 18/2100Z:  Solar activity was at low levels.  The largest flare
was a C3 at 18/0823Z from old Region 1476 (N10, L=180), which
rotated off the disk.  A filament eruption was observed in SDO/AIA
304 imagery beginning at 18/0510Z near Region 1482 (N15W17).  An
associated CME was observed in STEREO A COR 2 imagery beginning at
18/0709Z with an estimated plane-of-sky speed of approximately 482
km/s.  The majority of the ejecta appeared to be slightly north of
the ecliptic plane, however a glancing blow is likely.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
low levels with a slight chance for an M-class flare all three days
(19 - 21 May).
IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was at quiet to unsettled levels.  The greater
than 100 MeV proton event at geosynchronous orbit that began at
17/0200Z, reached a maximum of 20.4 pfu at 17/0230Z and ended at
17/1725Z.  The greater than 10 MeV proton event is currently
hovering close to the 10 pfu threshold (S1).
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at quiet to unsettled levels with isolated active
periods on day 1 (19 May) due to a possible shock arrival from the
17 May CME.  Quiet to unsettled conditions are expected on day 2 (20
May).  Mostly quiet conditions are expected on day 3 (21 May). 
There is a slight chance for shock enhancement of the greater than
10 MeV protons above 10 pfu on day 1.
III.  Event Probabilities 19 May-21 May
Class M    10/10/10
Class X    01/01/01
Proton     20/05/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           18 May 132
Predicted   19 May-21 May  135/135/130
90 Day Mean        18 May 115
V.  Geomagnetic A Indices
Observed Afr/Ap 17 May  005/004
Estimated Afr/Ap 18 May  008/008
Predicted Afr/Ap 19 May-21 May  009/010-008/008-006/005
VI.  Geomagnetic Activity Probabilities 19 May-21 May
A.  Middle Latitudes
Active                25/10/05
Minor storm           15/05/01
Major-severe storm    05/01/01
B.  High Latitudes
Active                30/15/10
Minor storm           20/10/05
Major-severe storm    05/01/01