:Product: 19991221RSGA.txt
:Issued: 1999 Dec 21 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 355 ISSUED AT 2200Z ON 21 DEC 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  20/2100Z
TO 21/2100Z:  SOLAR ACTIVITY WAS MODERATE. REGION 8806 (N19E24)
PRODUCED AN M1/1N AT 21/1719UT. REGION 8806 IS THE LARGEST REGION ON
THE DISK AND CONTINUES TO BE MAGNETICALLY COMPLEX.  REGION 8798
(S13W33), THE SECOND LARGEST REGION ON THE DISK, HAS ONLY PRODUCED
SMALL C FLARES.  A CME WAS OBSERVED BY SOHO AROUND 1600UT ON THE
20TH, BUT APPEARED TO BE A BACKSIDE EVENT.  THE OBSERVED 10CM RADIO
FLUX REPORTED IN PART IV MAY BE FLARE ENHANCED.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE.  THERE IS A FAIR CHANCE FOR MAJOR ACTIVITY FROM EITHER
REGION 8798 OR REGION 8806.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 20/2100Z TO 21/2100Z:
THE GEOMAGNETIC FIELD HAS BEEN BASICALLY QUIET.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED.
III.  EVENT PROBABILITIES 22 DEC-24 DEC
CLASS M    50/50/50
CLASS X    15/15/15
PROTON     05/05/10
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           21 DEC 217
PREDICTED   22 DEC-24 DEC  200/195/190
90 DAY MEAN        21 DEC 172
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 20 DEC  004/003
ESTIMATED AFR/AP 21 DEC  004/005
PREDICTED AFR/AP 22 DEC-24 DEC  007/010-007/007-005/007
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 22 DEC-24 DEC
A.  MIDDLE LATITUDES
ACTIVE                25/10/10
MINOR STORM           10/01/01
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                25/20/15
MINOR STORM           10/05/01
MAJOR-SEVERE STORM    01/01/01