:Product: 19971123RSGA.txt
:Issued: 1997 Nov 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 327 ISSUED AT 2200Z ON 23 NOV 1997
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY WAS LOW. REGION 8108 (N19W52) PRODUCED
TWO SMALL C-CLASS EVENTS. THE DELTA CONFIGURATION IN THIS REGION
FADED AND AREAL COVERAGE IN WHITE LIGHT DECREASED. SOME MINOR MIXED
POLARITIES REMAINED BUT OVERALL THE REGION SIMPLIFIED. OLD REGION
8100 RETURNED AS A BROAD DIFFUSE PLAGE WITH ONE SMALL SPOT. THIS
AREA IS NOW NUMBERED AS REGION 8112 (S17E59).
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD CONTINUE AT A
LOW LEVEL. REGION 8108 SHOULD PRODUCE INFREQUENT C-CLASS EVENTS.
CONTINUED DECAY IN THIS REGION WILL REDUCE THE ACTIVITY LEVEL TO
VERY LOW.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
THE GEOMAGNETIC FIELD BEGAN THE PERIOD AT ACTIVE TO MINOR STORM
LEVELS AND QUICKLY ESCALATED TO MINOR TO SEVERE STORM FROM
23/0000-1500Z. A MODERATE (7 PERCENT) FORBUSH DECREASE PEAKED NEAR
22/2200Z. THE REMAINDER OF THE PERIOD SAW QUIET TO UNSETTLED
CONDITIONS. SOLAR WIND VELOCITY REACHED OVER 600 KM/S AT THE END OF
THE PERIOD. IT IS POSSIBLE THE EARTH IS ENGULFED IN A MAGNETIC
CLOUD. THIS POSSIBILITY IS BASED UPON VERY LITTLE BZ DATA FROM LATE
ON 22 NOV SO THIS DETERMINATION MUST BE CONSIDERED SPECULATIVE.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
QUIET TO ACTIVE ON 24 NOV AS THE CURRENT DISTURBANCE SUBSIDES.
ISOLATED MINOR TO POSSIBLY MAJOR STORM PERIODS COULD BE EXPERIENCED
EARLY ON THAT DAY. UNSETTLED CONDITIONS ARE FORECAST FOR 25 NOV AND
QUIET SHOULD RETURN ON 26 NOV.
III.  EVENT PROBABILITIES 24 NOV-26 NOV
CLASS M    15/15/15
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 NOV 100
PREDICTED   24 NOV-26 NOV  100/100/098
90 DAY MEAN        23 NOV 092
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 NOV  034/045
ESTIMATED AFR/AP 23 NOV  041/060
PREDICTED AFR/AP 24 NOV-26 NOV  020/015-010/010-005/005
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 NOV-26 NOV
A.  MIDDLE LATITUDES
ACTIVE                35/20/10
MINOR STORM           20/10/05
MAJOR-SEVERE STORM    10/05/01
B.  HIGH LATITUDES
ACTIVE                40/20/10
MINOR STORM           25/10/05
MAJOR-SEVERE STORM    15/05/01