:Product: 19990525RSGA.txt
:Issued: 1999 May 25 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 145 ISSUED AT 2200Z ON 25 MAY 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  24/2100Z
TO 25/2100Z:  SOLAR ACTIVITY WAS LOW.  THE PERIOD WAS CHARACTERIZED
BY A NUMBER OF VERY WEAK C-CLASS X-RAY AND OPTICAL FLARES.  TWO
REGIONS WERE NUMBERED TODAY.  THE FIRST, REGION 8553 (N25W02) ,
BEGAN THE PERIOD AS A SOUTHWEST EXTENSION TO REGION 8551 (N32E10).
THE SECOND, REGION 8554 (N27E39), FORMED OVERNIGHT.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO REMAIN
LOW WITH A SLIGHT CHANCE FOR AN ISOLATED M-CLASS X-RAY FLARE.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 24/2100Z TO 25/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO MINOR STORM LEVELS.  THE
MOST ACTIVE CONDITIONS WERE SEEN OVERNIGHT AND IN THE EARLY MORNING
HOURS.  THESE CONDITIONS WERE DUE TO THE EFFECT OF A SMALL CORONAL
HOLE AS WELL AS THE IMPACT OF A TRANSIENT FEATURE THAT BROUGHT A
SUSTAINED PERIOD OF SOUTHWARD BZ.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED.  AS THE EFFECT OF THE CURRENT
CORONAL HOLE DIMINISHES, ANOTHER RECURRENT HOLE IS EXPECTED BY THE
SECOND DAY OF THE FORECAST PERIOD.
III.  EVENT PROBABILITIES 26 MAY-28 MAY
CLASS M    30/30/30
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           25 MAY 143
PREDICTED   26 MAY-28 MAY  145/145/150
90 DAY MEAN        25 MAY 129
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 24 MAY  011/011
ESTIMATED AFR/AP 25 MAY  015/019
PREDICTED AFR/AP 26 MAY-28 MAY  012/012-010/010-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 26 MAY-28 MAY
A.  MIDDLE LATITUDES
ACTIVE                20/20/20
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                25/25/25
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01