:Product: 19970527RSGA.txt
:Issued: 1997 May 27 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 147 ISSUED AT 2200Z ON 27 MAY 1997
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  26/2100Z
TO 27/2100Z:  SOLAR ACTIVITY WAS LOW. REGION 8045 (N02W85) PRODUCED A
C4/1F FLARE AT 0957UT. THIS GROUP SHOWED AN INCREASE IN ACTIVITY AND
BRIGHTNESS EARLY IN THE PERIOD AND PRODUCED SEVERAL ADDITIONAL
SUBFLARES IN ADDITION TO THE 1F MENTIONED PREVIOUSLY. NEW REGION
8047 (N26E70) ROTATED INTO VIEW TODAY AS A SIMPLE, STABLE BETA
SUNSPOT GROUP. REGION 8046 (S26E14) WAS QUIET AND APPEARS TO BE IN
DECAY.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE VERY
LOW FOR THE NEXT 24 HOURS, BUT WITH A CHANCE FOR AN ISOLATED C-CLASS
X-RAY FLARE FROM REGION 8045 AS IT CROSSES THE WEST LIMB. VERY LOW
CONDITIONS SHOULD PREVIAL FOR THE SECOND AND THIRD DAYS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 26/2100Z TO 27/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED FROM 26/2100-27/0300Z.
MOSTLY ACTIVE CONDITIONS WITH MINOR-MAJOR STORM PERIODS WERE
OBSERVED BETWEEN 0300-0900Z. ACTIVITY ABRUPTLY CEASED AT 0900Z, AND
THE GEOMAGNETIC FIELD HAS BEEN QUIET SINCE THEN. WIND DATA DID NOT
SHOW AN OBVIOUS SOURCE, BUT INDICATED STEADY SOUTHWARD BZ, SLIGHTLY
ENHANCED DENSITY, AND NOMINAL VELOCITIES. THUS THE SIGNATURE WOULD
BE MORE CONSISTENT WITH THE PROPERTIES OF TRANSIENT PHENOMENA THAN
WITH THOSE OF A HIGH-SPEED CORONAL HOLE STREAM.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT THREE DAYS.
III.  EVENT PROBABILITIES 28 MAY-30 MAY
CLASS M    01/01/01
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           27 MAY 078
PREDICTED   28 MAY-30 MAY  075/073/072
90 DAY MEAN        27 MAY 074
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 26 MAY  009/008
ESTIMATED AFR/AP 27 MAY  015/022
PREDICTED AFR/AP 28 MAY-30 MAY  010/015-010/010-010/008
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 28 MAY-30 MAY
A.  MIDDLE LATITUDES
ACTIVE                10/05/05
MINOR STORM           05/05/01
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                10/05/05
MINOR STORM           05/05/01
MAJOR-SEVERE STORM    01/01/01