:Product: 19980613RSGA.txt
:Issued: 1998 Jun 13 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 164 ISSUED AT 2200Z ON 13 JUN 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  12/2100Z
TO 13/2100Z:  SOLAR ACTIVITY WAS MODERATE DUE TO AN M1 X-RAY EVENT AT
0420Z. AN EXAMINATION OF GOES X-RAY DATA SHOWED THAT THIS LEVEL
RESULTED FROM THE SUPERPOSITION OF A SHORT, IMPULSIVE 1N FLARE FROM
REGION 8242 (S23E42) ON TOP OF A LONG DURATION X-RAY EVENT. THE LONG
DURATION EVENT BEGAN AT ABOUT 03Z AND CONTINUED THROUGH ABOUT 08Z.
DURING THIS SAME INTERVAL A SERIES OF LASCO IMAGES (STARTING AT 0355
AND ENDING AT 0730Z) SHOWED TRANSIENT MATERIAL MOVING OFF OF THE
WEST LIMB. REGION 8242 PRODUCED ADDITIONAL C-CLASS SUBFLARES DURING
THE DAY. REGION 8237 (S24W08) PRODUCED A C-CLASS EVENT AT 1554Z
WHICH WAS ACCOMPANIED BY PARALLEL H-ALPHA FLARE RIBBONS. NEW REGION
8245 (S19E15) EMERGED ON THE DISK AND SHOWED STEADY GROWTH. NEW
REGION 8246 WAS ASSIGNED TO THE SPOTS THAT EMERGED NEAR N14W48, JUST
EAST OF REGION 8234 (N16W57). REGION 8240 HAS NOW ROTATED BEYOND THE
WEST LIMB.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
PREDOMINANTLY LOW. THERE IS A SLIGHT CHANCE FOR AN ISOLATED M-CLASS
EVENT, WITH REGION 8242 AS THE MOST LIKELY SOURCE.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 12/2100Z TO 13/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET FROM THE BEGINNING OF THE PERIOD
THROUGH 1927Z WHEN A WEAK (BUT NOT SUDDEN) IMPULSE WAS OBSERVED ON
THE DAYSIDE MAGNETOMETERS. THE IMPULSE WAS PRECEDED BY COMPRESSION
SIGNATURE AT ACE AT 1855Z. THE L1 DATA SHOWED MANY FEATURES SIMILAR
TO A SHOCK (ENHANCED VELOCITY, DENSITY, TEMPERATURE AND MAGNETIC
FIELDS), BUT CHANGED OVER A LONGER TIME INTERVAL THAN A TRUE SHOCK
(ABOUT 5 MINUTES), SUGGESTING THAT L1 WAS EITHER ON THE FLANKS OF A
FAST CME OR WAS AHEAD OF A RELATIVELY SLOW CME. THE FORMER SEEMS
MORE LIKELY, GIVEN THE CLEAR OBSERVATIONS OF TRANSIENT ACVITITY FROM
THE EAST LIMB ON THE 11TH. THE GEOMAGNETIC ACTIVITY LEVELS RESPONDED
MILDLY BY INCREASING FROM QUIET TO UNSETTLED LEVELS FOR THE
REMAINDER OF THE PERIOD.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE GENERALLY UNSETTLED FOR THE NEXT 24 HOURS. QUIET TO
UNSETTLED LEVELS ARE EXPECTED TO PREDOMINATE FOR THE SECOND AND
THIRD DAYS.
III.  EVENT PROBABILITIES 14 JUN-16 JUN
CLASS M    20/20/20
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           13 JUN 111
PREDICTED   14 JUN-16 JUN  110/105/105
90 DAY MEAN        13 JUN 110
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 12 JUN  006/008
ESTIMATED AFR/AP 13 JUN  005/005
PREDICTED AFR/AP 14 JUN-16 JUN  005/010-005/010-005/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 14 JUN-16 JUN
A.  MIDDLE LATITUDES
ACTIVE                10/10/10
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                10/10/10
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01