:Product: 19980903RSGA.txt
:Issued: 1998 Sep 03 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 246 ISSUED AT 2200Z ON 03 SEP 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  02/2100Z
TO 03/2100Z:  SOLAR ACTIVITY REMAINED AT MODERATE LEVELS WITH TWO
M-CLASS FLARES DETECTED DURING THE PERIOD. THE FIRST OCCURRED AT
03/0421Z AND WAS LINKED (VIA YOHKOH SXT OBSERVATIONS) TO NEW REGION
8326 (N19E73) BY VIRTUE OF A BRIGHT LOOP STRUCTURE SEEN ABOVE THE
REGION FOLLOWING THE FLARE. A LOOP PROMINENCE SYSTEM WAS ALSO
OBSERVED ABOVE THIS REGION LATER IN THE DAY FOLLOWING A SUBFAINT
FLARE. NEW REGION 8326 APPEARS TO BE THE RETURN OF OLD REGION 8299,
WHICH PRODUCED ISOLATED M-CLASS FLARES DURING ITS PREVIOUS ROTATION.
THE SECOND WAS A LONG-DURATION M1/SF FROM REGION 8323 (S22E03) AT
03/1608Z. THIS REGION ALSO PRODUCED A LONG-DURATION C3/SF FLARE AT
03/1430Z ACCOMPANIED BY A STRONG TYPE II RADIO SWEEP AND MINOR
DISCRETE RADIO EMISSIONS. REGION 8323 REMAINED LARGE WITH MODERATE
MAGNETIC COMPLEXITY, BUT SHOWED NO SIGNIFICANT CHANGES AS IT BEGAN
CROSSING INTO THE WESTERN HEMISPHERE. NEW REGION 8327 (N30E78) WAS
ALSO NUMBERED.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. M-CLASS FLARES ARE POSSIBLE FROM REGIONS 8323 AND 8326.
THERE IS ALSO A FAIR CHANCE FOR A MAJOR FLARE FROM REGION 8323.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 02/2100Z TO 03/2100Z:
THE GEOMAGNETIC FIELD WAS AT MOSTLY QUIET TO UNSETTLED LEVELS WITH
ISOLATED ACTIVE PERIODS REPORTED AT SOME HIGH LATITUDE STATIONS. THE
GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ALTITUDE WAS AT
MODERATE TO HIGH LEVELS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO CONTINUE AT QUIET TO UNSETTLED LEVELS WITH BRIEF ACTIVE
PERIODS POSSIBLE AT HIGH LATITUDES DURING THE FIRST DAY. THE GREATER
THAN 2 MEV ELECTRON FLUX IS EXPECTED TO DECLINE TO NORMAL TO
MODERATE LEVELS ON THE LAST DAY OF THE FORECAST PERIOD.
III.  EVENT PROBABILITIES 04 SEP-06 SEP
CLASS M    70/70/70
CLASS X    20/20/20
PROTON     20/20/20
PCAF       YELLOW
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           03 SEP 163
PREDICTED   04 SEP-06 SEP  160/160/155
90 DAY MEAN        03 SEP 122
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 02 SEP  007/008
ESTIMATED AFR/AP 03 SEP  007/008
PREDICTED AFR/AP 04 SEP-06 SEP  012/012-010/012-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 04 SEP-06 SEP
A.  MIDDLE LATITUDES
ACTIVE                30/25/20
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    05/01/01
B.  HIGH LATITUDES
ACTIVE                35/30/25
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    05/01/01