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TROPICAL STORM AGATHA DISCUSSION NUMBER  15
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT SUN JUN 14 1998

IN SPITE OF BEING OVER SEA SURFACE TEMPERATURES ESTIMATED AROUND 23
DEGREES CELSIUS...THE STORM HAS MAINTAINED SOME DEEP CONVECTION
AROUND ITS CENTER.  CURRENT INTENSITY IS HELD AT 45 KNOTS FOLLOWING
DVORAK ESTIMATES FROM TAFB MIAMI AND SAB WASHINGTON.  SOUTHWESTERLY
VERTICAL SHEAR IS FORECAST TO INCREASE OVER AGATHA AND COOLER WATERS
SHOULD EVENTUALLY TAKE THEIR TOLL ON THE TROPICAL CYCLONE. 
WEAKENING TO A DEPRESSION IS FORECAST WITHIN 24 HOURS OR SO.  THE
SYSTEM SHOULD BE DISSIPATING LATER IN THE FORECAST PERIOD.

AGATHA IS NEARING THE WESTERN PERIPHERY OF A MID-TROPOSPHERIC RIDGE
AND IS CURRENTLY MOVING NORTHWESTWARD AROUND 9 KNOTS.  SOME FURTHER
SLOWING OF THE FORWARD SPEED IS EXPECTED.  IF THIS WERE A STRONGER
SYSTEM...AGATHA WOULD PROBABLY BEGIN TO RECURVE AROUND THE RIDGE AND
BE STEERED NORTHWARD AND NORTH-NORTHEASTWARD DUE TO A MID- TO UPPER-
LEVEL TROUGH OR CYCLONIC SHEAR AXIS EXTEND SOUTHWESTWARD FROM
NORTHERN BAJA.  AGATHA IS A RATHER WEAK STORM HOWEVER...AND ITS
MOTION IS MORE LIKELY TO BE CONTROLLED BY SHALLOWER-LAYER
STEERING...I.E. THE TRADEWINDS.  OUR TRACK MODELS CONTINUE TO BE
HIGHLY DIVERGENT...AND AT THIS TIME THE MOST PRUDENT FORECAST SEEMS
TO BE A MAINTENANCE OF A SLOW NORTHWEST TO WEST-NORTHWEST MOTION. 
THIS IS SIMILAR TO THE PREVIOUS FORECAST. 

PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     15/0300Z 19.2N 120.9W    45 KTS
12HR VT     15/1200Z 20.0N 122.0W    35 KTS
24HR VT     16/0000Z 20.7N 123.2W    30 KTS
36HR VT     16/1200Z 21.2N 124.0W    25 KTS...DISSIPATING
48HR VT     17/0000Z 21.5N 124.5W    25 KTS...DISSIPATING
72HR VT     18/0000Z 22.0N 125.5W    20 KTS...DISSIPATING
 
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