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TROPICAL DEPRESSION OLIVIA DISCUSSION NUMBER  29
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT MON OCT 09 2000
 
OLIVIA IS DEVOID OF AN DEEP CONVECTION NEAR THE FULLY EXPOSED LOW-
LEVEL CENTER...ALTHOUGH A FEW WEAK CONVECTIVE BANDS HAVE REDEVELOPED
ON THE SOUTH SIDE DURING THE PAST COUPLE OF HOURS.  SATELLITE
INTENSITY ESTIMATES FROM TAFB AND KGWC YIELD 30 KT WITH 25 KT COMING
IN FROM SAB...SO THE INITIAL INTENSITY IS HELD AT 30 KT.
 
THE INITIAL MOTION IS NOW 310/9.  ALL OF THE MODELS AGREE ON GRADUAL
RECURVATURE TO THE NORTHEAST IN ABOUT 24 TO 36 HOURS...EXCEPT FOR
CLIPER WHICH KEEPS OLIVIA TRACKING TO THE NORTHWEST.  HOWEVER...THE
STRONG SURFACE RIDGE TO THE NORTH AND NORTHWEST SHOULD PREVENT ANY
SIGNIFICANT NORTHWEST MOTION.  THE MAIN QUESTION IS HOW DEEP WILL
THE REMNANT CIRCULATION OF OLIVIA BE IN 24 HOURS.  THE DEEP LAYER
STEERING FLOW SUGGESTS RECURVATURE...BUT A SHALLOW SYSTEM WOULD MOST
LIKELY TAKE A SLOWER NORTHWEST TRACK...STALL...AND THEN DISSIPATE. 
THE OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS TRACK AND RECURVES
OLIVIA TO THE NORTHEAST IN THE MIDDLE OF MOST OF THE MODEL GUIDANCE.
 
WATER VAPOR AND INFRARED IMAGERY SUGGEST THAT THE EASTERLY VERTICAL
SHEAR IS DECREASING AS OLIVIA MOVES POLEWARD BENEATH A 200 MB RIDGE
AXIS.  THIS PATTERN WOULD GENERALLY FAVOR INTENSIFICATION...EXCEPT
THAT THE CYCLONE IS MOVING OVER COOL WATER WITH SSTS BELOW 26C. 
THERE ARE ALSO COLD AIR STRATOCUMULUS CLOUDS BEGINNING TO WRAP INTO
THE WESTERN HALF OF THE LOW-LEVEL CIRCULATION.  HOWEVER...THERE IS
STILL ENOUGH WARM UNSTABLE AIR TO THE SOUTHEAST AND SOUTH THAT COULD
PROVIDE ENOUGH ENERGY FOR ONE FINAL BURST OF CONVECTION TONIGHT
DURING THE DIURNAL CONVECTIVE MAXIMUM PERIOD.  FOR THAT REASON...I
AM A LITTLE HESITANT TO DISSIPATE OLIVIA IN 24 TO 36 HOURS. 
HOWEVER...IF CONVECTION DOES NOT REDEVELOP TONIGHT...THEN THE SYSTEM
WILL LIKELY SPIN DOWN AND DISSIPATE BY TOMORROW...IF NOT SOONER. 
THE SHIPS MODEL DISSIPATES OLIVIA BY 36 HOURS.

NOTE...12 FT SEAS RADII WERE ADDED TO THE MARINE/FORECAST ADVISORY
BASED ON A 14 FT REPORT AT 09/12Z FROM SHIP VRVS5 TO THE SOUTHWEST.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     09/1500Z 20.3N 117.7W    30 KTS
12HR VT     10/0000Z 21.2N 118.3W    25 KTS
24HR VT     10/1200Z 22.7N 118.3W    25 KTS
36HR VT     11/0000Z 24.6N 116.8W    20 KTS...DISSIPATING
48HR VT     11/1200Z 26.5N 113.5W    20 KTS...DISSIPATED
 
 
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