:Product: 19990723RSGA.txt
:Issued: 1999 Jul 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 204 ISSUED AT 2200Z ON 23 JUL 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY BECAME MODERATE. NEW REGION 8644
(S24E69) PRODUCED AN M1 AT 23/1601Z. THE BIG BEAR OBSERVATORY
REPORTED A FLARE BRIGHT KNOT OF MATERIAL AT THE SOUTHEAST LIMB AT
THE TIME OF THE X-RAY BURST. THERE MAY BE A REGION BEHIND 8644 THAT
WAS THE PRIMARY SOURCE OF THE X-RAY BURST. THIS WOULD BE NEAR THE
LOCATION OF THE RETURN OF OLD REGION 8611 THAT PRODUCED 5 M-CLASS
EVENTS LAST ROTATION. REGION 8636 (N21W02) GREW SLOWLY DURING THE
PERIOD AND SIMPLIFIED. THE WEAK DELTA CONFIGURATION VISIBLE IN THIS
REGION ON 22 JUL FADED. REGION 8636 PRODUCED A VERY LONG DURATION
M1/2F THAT BEGAN AT 23/1832Z AND REACHED MAXIMUM AT 23/2005Z.
SEVERAL MID TO HIGH LEVEL C-CLASS FLARES WERE PRODUCED BY THIS
REGION.  REGION 8639 (N38W60) GREW AT A MODERATE PACE AND EXHIBITED
A STRAIGHT BIPOLAR, BUT REVERSE POLARITY, CONFIGURATION.
IB.  SOLAR ACTIVITY FORECAST:  AT A MINIMUM, SOLAR ACTIVITY SHOULD
CONTINUE AT MODERATE LEVELS FOR THE NEXT THREE DAYS. REGIONS 8636,
8639, AND 8644 (OR THE REGION BEHIND IT) ARE CAPABLE OF PRODUCING
M-CLASS EVENTS. REGION 8636 COULD PRODUCE AN X-CLASS EVENT DURING
THE PERIOD.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
THE GEOMAGNETIC FIELD WAS PREDOMINANTLY UNSETTLED WITH BRIEF QUIET
PERIODS. SOLAR WIND VELOCITY BEGAN TO DECREASE DURING THE PERIOD BUT
REMAINED ABOVE NORMAL.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
QUIET TO UNSETTLED FOR THE NEXT THREE DAYS. ISOLATED ACTIVE
CONDITIONS ARE POSSIBLE ON 24-25 JUL. SHOULD REGION 8636 PRODUCE A
LARGE FLARE, IT WOULD LIKELY HAVE THE CHARACTERISTICS (LARGE AREA,
LONG DURATION, AND CME CREATION) TO PRODUCE A SOLAR PROTON EVENT AT
THE EARTH.
III.  EVENT PROBABILITIES 24 JUL-26 JUL
CLASS M    90/90/90
CLASS X    20/20/20
PROTON     20/20/20
PCAF       YELLOW
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 JUL 194
PREDICTED   24 JUL-26 JUL  175/178/180
90 DAY MEAN        23 JUL 155
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 JUL  023/024
ESTIMATED AFR/AP 23 JUL  010/012
PREDICTED AFR/AP 24 JUL-26 JUL  012/012-012/012-008/008
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 JUL-26 JUL
A.  MIDDLE LATITUDES
ACTIVE                30/20/20
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/05/01
B.  HIGH LATITUDES
ACTIVE                40/35/30
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/05/01