:Product: 19991220RSGA.txt
:Issued: 1999 Dec 20 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Environment Center and the U.S. Air Force.
#
JOINT USAF/NOAA REPORT OF SOLAR AND GEOPHYSICAL ACTIVITY
SDF NUMBER 354 ISSUED AT 2200Z ON 20 DEC 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  19/2100Z
TO 20/2100Z:  SOLAR ACTIVITY HAS BEEN LOW.  SOLAR X-RAY BACKGROUND IS
RUNNING NEAR THE C LEVEL, RESULTING IN NUMEROUS SMALL C CLASS
EVENTS.  THERE ARE TWO MAJOR COMPLEXES CURRENTLY VISIBLE, REGION
8798 (S12 W20) AND REGION 8806 (N18E37).  BOTH THESE REGIONS ARE
MAGNETICALLY COMPLEX, WITH DELTAS, HOWEVER, ONLY MINOR PLAGE
ENHANCEMENTS ARE BEING OBSERVED.  SMALL REGION 8803 (S12W30) IS
EMBEDDED IN THE LEADING POLARITY PLAGE OF REGION 8798.  REGION 8807
(N10 E43) IS LOCATED IN AN OLD PLAGE JUST SOUTH OF REGION 8806.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE, HOWEVER, MAJOR FLARES ARE POSSIBLE FROM REGIONS 8798
(S12W20) AND 8806 (N18E37).
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 19/2100Z TO 20/2100Z:
THE GEOMAGNETIC FIELD HAS BEEN BASICALLY QUIET.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED.  THERE IS AN INCREASING CHANCE
FOR AN ENERGETIC PARTICLE EVENT FROM EITHER THE REGION 8798 OR
REGION 8806 COMPLEXES NOW VISIBLE.
III.  EVENT PROBABILITIES 21 DEC-23 DEC
CLASS M    50/50/50
CLASS X    15/20/20
PROTON     05/05/10
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           20 DEC 209
PREDICTED   21 DEC-23 DEC  205/200/195
90 DAY MEAN        20 DEC 171
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 19 DEC  006/004
ESTIMATED AFR/AP 20 DEC  003/003
PREDICTED AFR/AP 21 DEC-23 DEC  008/012-010/012-007/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 21 DEC-23 DEC
A.  MIDDLE LATITUDES
ACTIVE                25/25/10
MINOR STORM           10/10/01
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                25/25/15
MINOR STORM           10/10/01
MAJOR-SEVERE STORM    01/01/01