:Product: 19980831RSGA.txt
:Issued: 1998 Aug 31 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 243 ISSUED AT 2200Z ON 31 AUG 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  30/2100Z
TO 31/2100Z:  SOLAR ACTIVITY WAS MODERATE. REGION 8307 (N31W76)
PRODUCED AN IMPULSIVE M1/SF FLARE AT 1539Z WHICH WAS ACCOMPANIED BY
A TYPE II RADIO SWEEP. THE REGION ALSO PRODUCED TWO C-CLASS FLARES
DURING THE PAST 24 HOURS. REGION 8319 (N18W54) CONTINUED TO GROW
TODAY, BUT NOT AS RAPIDLY AS YESTERDAY. FLARES FROM THIS GROUP
OCCURRED LESS FREQUENTLY THAN YESTERDAY AND CONSISTED OF A FEW
C-CLASS SUBFLARES. THE GROUP HAS STRONG MAGNETIC FIELDS THAT ARE IN
A BETA CONFIGURATION WITH A NORTH-SOUTH INVERSION LINE. REGION 8323
(S21E54) HAS ROTATED INTO VIEW AS A LARGE COMPACT GROUP. THERE
APPEARS TO BE A DELTA CONFIGURATION IN A PENUMBRAL AREA NEAR THE
MIDDLE OF THE GROUP. IN SPITE OF THE SIZE AND COMPLEXITY OF THE
GROUP IT PRODUCED ONLY A FEW C-CLASS SUBFLARES DURING THE PAST 24
HOURS.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. THERE CONTINUES TO BE A CHANCE, HOWEVER, FOR A MAJOR FLARE
EVENT FROM ANY OF REGIONS 8307, 8319, OR 8323.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 30/2100Z TO 31/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS, WITH SOME
MINOR STORM PERIODS AT HIGH LATITUDES. A QUIET TO UNSETTLED FIELD
BECAME ACTIVE TO MINOR STORM BETWEEN 0600-1200Z. REAL-TIME SOLAR
WIND CONTINUES TO SHOW THE SAME HIGH SPEED, LOW DENSITY SOLAR WIND
THAT HAS PERSISTED OVER THE LAST 4 DAYS. THE INTERPLANETARY MAGNETIC
FIELD, HOWEVER, TRANSITIONED TO A MORE CONSISTENTLY SOUTHWARD
DIRECTION (MOSTLY FROM -3 TO -7 NT), DURING THE ENHANCED GEOMAGNETIC
ACTIVITY INTERVAL. THE FIELD CONTINUED TO BE ACTIVE FROM 1200-1800Z,
BUT APPEARED TO BE CALMING SOMEWHAT DURING THE LAST 3 HOURS. THE
GREATER THAN 2 MEV ELECTRON FLUX CONTINUES TO BE HIGH.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED WITH OCCASIONAL ACTIVE PERIODS OVER
THE NEXT THREE DAYS.
III.  EVENT PROBABILITIES 01 SEP-03 SEP
CLASS M    70/65/60
CLASS X    20/20/15
PROTON     25/20/15
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           31 AUG 179
PREDICTED   01 SEP-03 SEP  180/175/175
90 DAY MEAN        31 AUG 120
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 30 AUG  011/015
ESTIMATED AFR/AP 31 AUG  015/023
PREDICTED AFR/AP 01 SEP-03 SEP  015/015-015/015-015/012
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 01 SEP-03 SEP
A.  MIDDLE LATITUDES
ACTIVE                50/45/40
MINOR STORM           20/20/20
MAJOR-SEVERE STORM    10/10/10
B.  HIGH LATITUDES
ACTIVE                40/40/40
MINOR STORM           30/30/30
MAJOR-SEVERE STORM    15/15/15