:Product: 19991228RSGA.txt
:Issued: 1999 Dec 28 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 362 ISSUED AT 2200Z ON 28 DEC 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  27/2100Z
TO 28/2100Z:  SOLAR ACTIVITY WAS MODERATE.  REGION 8806 (N20W65)
PRODUCED AN M4/2B FLARE AT 28/0039UT.  THIS EVENT WAS ACCOMPANIED BY
MODERATE RADIO EMISSIONS, INCLUDING A TYPE II SWEEP.  REGION 8806
CONTINUES TO DECLINE AS IT APPROACHES THE WEST LIMB.  ONLY MINOR
ACTIVITY WAS OBSERVED IN THE OTHER THREE SPOTTED REGIONS.  THE
PROMINENCE THAT ERUPTED AROUND 27/2100UT APPEARS IN THE SOHO IMAGERY
TO COVER MUCH OF THE NORTHERN POLAR AREA.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 27/2100Z TO 28/2100Z:
THE GEOMAGNETIC FIELD WAS MOSTLY QUIET.  A SHORT PERIOD OF UNSETTLED
CONDITIONS WAS OBSERVED AROUND 0300UT.  THERE WERE ONLY MINOR
PARTICLE ENHANCEMENTS FOLLOWING THE 28/0039UT M4/2B FLARE.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED EARLY IN THE PERIOD.  THE FIELD IS
EXPECTED TO BECOME DISTURBED STARTING ON 31 DEC AS A RESULT OF A
LARGE EQUATORIAL CORONAL HOLE EAST OF CENTRAL MERIDIAN.
III.  EVENT PROBABILITIES 29 DEC-31 DEC
CLASS M    50/50/50
CLASS X    10/10/10
PROTON     10/10/10
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           28 DEC 150
PREDICTED   29 DEC-31 DEC  145/140/135
90 DAY MEAN        28 DEC 176
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 27 DEC  006/006
ESTIMATED AFR/AP 28 DEC  004/005
PREDICTED AFR/AP 29 DEC-31 DEC  005/005-008/010-012/012
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 29 DEC-31 DEC
A.  MIDDLE LATITUDES
ACTIVE                10/15/15
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                15/20/20
MINOR STORM           05/10/10
MAJOR-SEVERE STORM    01/01/01