:Product: 19980823RSGA.txt
:Issued: 1998 Aug 23 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 235 ISSUED AT 2200Z ON 23 AUG 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY WAS MODERATE. REGION 8307 (N31E22)
PRODUCED AN M2/1N FLARE AT 23/0934Z WITH A 2695 MHZ BURST OF 500
SFU. THIS REGION BEGAN A DECAY TREND DURING THE PERIOD. THE DELTA
CONFIGURATION REMAINED IN THE NORTHERN PORTION OF THE REGION BUT
OVERALL, THE MAGNETIC COMPLEXITY IS DECREASING. REGION 8310 (N24E33)
PRODUCED A C3/SF FLARE AT 23/1125Z.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BECOME
LOW TO MODERATE. CONTINUED DECAY AND SIMPLIFICATION IN REGION 8307
COULD RESULT IN A RAPID DECREASE OF FLARE PRODUCTION.  ONLY
OCCASIONAL M-CLASS EVENTS ARE EXPECTED FOR THE NEXT THREE DAYS.
X-CLASS FLARES REMAIN SLIGHTLY POSSIBLE FROM THIS REGION THAT
PRODUCED A TOTAL OF 4 X-CLASS EVENTS EARLY IN ITS VISIBLE HEMISPHERE
TRANSIT.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
THE GEOMAGNETIC FIELD WAS UNSETTLED AT MIDDLE LATITUDES AND UNSETTLED
TO MINOR STORM LEVELS AT HIGH LATITUDES. THE MOST DISTURBED PERIOD
WAS FROM 23/0000-0900Z. RECENT SOLAR WIND DATA SHOW AN INCREASE OF
SOLAR WIND VELOCITY TO NEAR 600 KM/S AND DECREASE OF DENSITY TO 2-3
P/CC. THESE PARAMETERS INDICATE THE EARTH IS EMBEDDED IN A CORONAL
HOLE STREAM. MAGNETIC DATA IMPLICATE THE EQUATORWARD EXTENSION OF
THE NORTHERN CORONAL HOLE AS THE SOURCE OF THIS STREAM. THE
ENERGETIC (GT 10 MEV) PROTON ENHANCEMENT THAT BEGAN ON 20 AUG
CONTINUED THROUGH THE PERIOD AT A FLUX OF APPROXIMATELY 2 PFU.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD
CONTINUE AT PREDOMINANTLY UNSETTLED TO ACTIVE LEVELS THROUGH 24 AUG.
MINOR STORM INTERVALS ARE POSSIBLE DURING THAT TIME. A SLIGHTLY MORE
INTENSE DISTURBANCE IS EXPECTED ON 25-26 AUG AS A RESULT OF THE M9
FLARE AND SUSPECTED CME OF 22 AUG. ACTIVE TO MINOR STORM LEVELS WITH
ISOLATED PERIODS OF MAJOR STORMING ARE POSSIBLE FOR THAT PERIOD. THE
PROTON ENHANCEMENT SHOULD DECAY SLOWLY OVER THE NEXT SEVERAL DAYS.
III.  EVENT PROBABILITIES 24 AUG-26 AUG
CLASS M    55/55/55
CLASS X    20/20/20
PROTON     20/20/20
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 AUG 126
PREDICTED   24 AUG-26 AUG  127/128/130
90 DAY MEAN        23 AUG 116
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 AUG  013/023
ESTIMATED AFR/AP 23 AUG  015/020
PREDICTED AFR/AP 24 AUG-26 AUG  020/020-025/020-025/030
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 AUG-26 AUG
A.  MIDDLE LATITUDES
ACTIVE                40/30/30
MINOR STORM           20/30/30
MAJOR-SEVERE STORM    05/15/15
B.  HIGH LATITUDES
ACTIVE                40/30/30
MINOR STORM           25/30/30
MAJOR-SEVERE STORM    10/20/20