[NCEP Logo] HOME ARCHIVES FORECASTS IMAGERY ABOUT TPC RECONNAISSANCE

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TROPICAL STORM CRISTINA DISCUSSION NUMBER  21
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT SUN JUL 14 2002
 
THERE REMAINS SOME UNCERTAINTY IN THE EXACT LOCATION OF THE
LOW-LEVEL CENTER AND...THEREFORE...THE INTENSITY.  EARLIER SSMI AND
TRMM MICROWAVE SUGGESTED THAT THE MID-LEVEL CIRCULATION/PARTIAL EYE
WAS DISPLACED TO THE EAST OF THE LOW-LEVEL CIRCULATION.  HOWEVER...
DURING THE PAST 6 HOURS...INFRARED DATA SUGGESTS THAT THE TWO
CENTERS ARE PERHAPS BECOMING MORE VERTICALLY ALIGNED.  THE INITIAL
INTENSITY ESTIMATE OF 55 KT IS BASED ON A BLEND OF SATELLITE
INTENSITY ESTIMATES OF 65 KT...55 KT...AND 45 KT FROM TAFB...SAB...
AND AFWA...RESPECTIVELY.  THE INTENSITY WAS HELD DOWN A LITTLE
BELOW THE TAFB ESTIMATE UNTIL VISIBLE IMAGERY BECOMES AVAILABLE WHEN
A BETTER CENTER ESTIMATE CAN BE MADE.

THE INITIAL MOTION ESTIMATE IS 325/07.  CRISTINA APPEARS TO BE
REMAINING ON TRACK...SO THE OFFICIAL FORECAST IS JUST AN UPDATE OF
THE PREVIOUS FORECAST TRACK.  WITH THE EXCEPTION OF THE NOGAPS AND
LBAR MODELS...THE REMAINDER OF THE NHC MODEL GUIDANCE REMAINS
TIGHTLY PACKED AROUND THE PAST 24 HOURS OF OFFICIAL FORECAST TRACKS.
WATER VAPOR IMAGERY SHOWS A STRONG TROUGH DIGGING SOUTHWARD TO THE
WEST OF CRISTINA...WHICH SHOULD ACT TO LIFT THE SYSTEM STEADILY
POLEWARD THROUGH THE NEXT 24 TO 36 HOURS.  AFTER THAT...THE CYCLONE
IS EXPECTED TO WEAKEN RAPIDLY AND...THEREFORE...DECOUPLE FROM THE
DEEP NORTHWESTWARD STEERING FLOW AND BE FORCED MORE WESTWARD BY THE
LOW-LEVEL EASTERLIES.  THE OFFICIAL FORECAST IS VERY CLOSE TO THE
AVN SOLUTION...GIVEN ITS OUTSTANDING PERFORMANCE THUS FAR WITH
ERRORS UNDER 100 NMI AT ALL TIME PERIODS.

THE WINDOW OF OPPORTUNITY FOR CRISTINA TO CONTINUE TO STRENGTHEN IS 
RAPIDLY CLOSING AS THE SYSTEM MOVES CLOSER TO MUCH COOLER SSTS. IN 
24 HOURS...THE CYCLONE IS EXPECTED TO MOVE OVER SUB 23C SST WATER... 
WHICH SHOULD START A RAPID WEAKENING TREND. HOWEVER...THERE IS STILL 
THE POSSIBILITY THAT CRISTINA COULD REACH MINIMAL HURRICANE STRENGTH 
WITHIN THE NEXT 12 HOURS BEFORE INCREASING VERTICAL SHEAR AND 
DECREASING WATER TEMPERATURES BRING ABOUT A RAPID DEMISE OF THIS 
CYCLONE.
  
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     14/1500Z 17.1N 118.4W    55 KTS
12HR VT     15/0000Z 18.1N 119.1W    60 KTS
24HR VT     15/1200Z 19.3N 120.4W    45 KTS
36HR VT     16/0000Z 19.6N 121.7W    35 KTS
48HR VT     16/1200Z 20.0N 123.5W    30 KTS...DISSIPATING
72HR VT     17/1200Z 20.3N 126.7W    20 KTS...DISSIPATING
 
 
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