:Product: 19980821RSGA.txt
:Issued: 1998 Aug 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 233 ISSUED AT 2200Z ON 21 AUG 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  20/2100Z
TO 21/2100Z:  SOLAR ACTIVITY BECAME LOW. REGION 8307 (N31E47)
PRODUCED A C1/SF FLARE AT 21/1620Z. SEVERAL OTHER SMALL TO MID
C-CLASS EVENTS OCCURRED BUT WERE NOT OPTICALLY CORRELATED WITH A
SPECIFIC REGION. CONFLICTING DATA HAVE BEEN RECEIVED REGARDING THE
GROWTH OR DECAY OF REGION 8307. TIGHT MAGNETIC GRADIENTS REMAINED IN
THIS REGION BUT BY TECHNICAL DEFINITION, THE DELTA CONFIGURATION
FADED. VECTOR MAGNETOGRAPH DATA ON REGION 8307 FROM 20 AUG DID NOT
SHOW LARGE AREAS OF HIGH SHEAR.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD BE GENERALLY LOW
TO MODERATE. REGION 8307 HAS SHOWN ITS CAPABILITY OF PRODUCING
X-CLASS EVENTS AND MORE REMAIN POSSIBLE.  HOWEVER, RECENT TRENDS
INDICATE A LESSENING IN THE RATE OF FLARE PRODUCTION FROM THIS
REGION.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 20/2100Z TO 21/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. SOLAR WIND DATA SHOW A
LOW VELOCITY FLOW IN THE EARTH'S VICINITY WITH PREDOMINANTLY
NORTHWARD BZ.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
QUIET TO SLIGHTLY ACTIVE FOR THE NEXT THREE DAYS. AN EQUATORWARD
EXTENSION OF THE NORTHERN POLAR CORONAL HOLE IS EXPECTED TO BEGIN TO
DISTURB THE GEOMAGNETIC FIELD DURING THE PERIOD.
III.  EVENT PROBABILITIES 22 AUG-24 AUG
CLASS M    70/70/70
CLASS X    30/30/30
PROTON     15/20/20
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           21 AUG 132
PREDICTED   22 AUG-24 AUG  135/138/139
90 DAY MEAN        21 AUG 115
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 20 AUG  014/018
ESTIMATED AFR/AP 21 AUG  005/008
PREDICTED AFR/AP 22 AUG-24 AUG  015/020-015/015-012/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 22 AUG-24 AUG
A.  MIDDLE LATITUDES
ACTIVE                30/30/30
MINOR STORM           15/15/15
MAJOR-SEVERE STORM    05/05/05
B.  HIGH LATITUDES
ACTIVE                30/30/30
MINOR STORM           15/15/15
MAJOR-SEVERE STORM    05/05/05