:Product: 19991120RSGA.txt
:Issued: 1999 Nov 20 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 324 ISSUED AT 2200Z ON 20 NOV 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  19/2100Z
TO 20/2100Z:  SOLAR ACTIVITY REMAINED AT LOW LEVELS. SEVERAL
SUBFLARES OCCURRED DURING THE PERIOD, A FEW OF WHICH REACHED
C-CLASS. REGION 8771 (S17E12) WAS RESPONSIBLE FOR MOST OF THE
SUBFLARE ACTIVITY. IT SHOWED NO SIGNIFICANT CHANGES AND MAINTAINED A
MIXED-POLARITY STRUCTURE, POSSIBLY INCLUDING A DELTA CONFIGURATION.
REGION 8765 (S13W47) WAS STABLE, BUT REMAINED THE LARGEST AND MOST
MAGNETICALLY COMPLEX GROUP ON THE DISK WITH STRONG DELTA
CONFIGURATIONS OBSERVED WITHIN ITS INTERMEDIATE AND TRAILER SPOTS.
REGION 8766 (N18W25) SHOWED A SLIGHT INCREASE IN MAGNETIC FIELD
STRENGTH AND MAINTAINED A MIXED-POLARITY STRUCTURE, POSSIBLY
INCLUDING A DELTA CONFIGURATION WITHIN ITS TRAILER SPOTS. REGION
8759 (N12W92) WAS STABLE AS IT DEPARTED THE WEST LIMB. NEW REGION
8776 (S31E24) WAS NUMBERED.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. REGIONS 8765, 8766, AND 8771 EACH APPEAR CAPABLE OF
PRODUCING M-CLASS FLARES. THERE IS ALSO A CHANCE FOR A MAJOR FLARE
DURING THE PERIOD, ESPECIALLY FROM REGION 8765.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 19/2100Z TO 20/2100Z:
GEOMAGNETIC FIELD ACTIVITY RANGED FROM QUIET TO ACTIVE LEVELS. A
UNSETTLED TO ACTIVE PERIOD OCCURRED DURING 20/0100 - 0300Z WITH
MINOR STORM LEVELS DETECTED AT SOME HIGH LATITUDE STATIONS. THIS
ACTIVITY FOLLOWED A BRIEF INCREASE IN SOLAR WIND VELOCITIES.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  GEOMAGNETIC ACTIVITY IS
EXPECTED TO RANGE FROM UNSETTLED TO ACTIVE LEVELS. ACTIVE LEVELS ARE
POSSIBLE ON DAY ONE IN RESPONSE TO RECENT CME ACTIVITY AND AGAIN ON
DAY THREE DUE TO CORONAL HOLE EFFECTS.
III.  EVENT PROBABILITIES 21 NOV-23 NOV
CLASS M    80/80/80
CLASS X    30/30/30
PROTON     20/20/20
PCAF       YELLOW
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           20 NOV 204
PREDICTED   21 NOV-23 NOV  200/200/190
90 DAY MEAN        20 NOV 167
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 19 NOV  009/012
ESTIMATED AFR/AP 20 NOV  012/012
PREDICTED AFR/AP 21 NOV-23 NOV  015/018-012/015-015/018
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 21 NOV-23 NOV
A.  MIDDLE LATITUDES
ACTIVE                30/20/35
MINOR STORM           15/10/15
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                40/30/40
MINOR STORM           20/15/20
MAJOR-SEVERE STORM    01/01/01