[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 210901
TCDAT3
TROPICAL STORM CRISTOBAL DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032008
500 AM EDT MON JUL 21 2008

THIS EVENING'S RECONNAISSANCE SFMR DATA INDICATED 40 KT IN THE EAST
QUADRANT AND 51 KT AT 850 MB.  OF 45 KT IN THE EAST AND SOUTHEAST
QUADRANTS. ADDITIONALLY...SFMR RECORDED 59 KT ON AN INBOUND LEG OVER
THE NORTHEAST PORTION OF THE CYCLONE.  THIS ANOMALOUS WIND APPEARS
TO HAVE BEEN DUE TO A LARGE CLUSTER OF THUNDERSTORMS WITH AN
ASSOCIATED WELL DEFINED OUTFLOW BOUNDARY...THAT EARLIER DETACHED
FROM THE LARGE ARE OF DEEP CONVECTION OVER THE EASTERN SIDE.
CONSEQUENTLY...THE INITIAL INTENSITY IS KEPT AT 45 KT AS A
COMPROMISE.  THE INTENSITY FORECAST REMAINS UNCHANGED...WITH THE
CYCLONE HOLDING ON TO THE CURRENT INTENSITY DURING THE NEXT 3
DAYS...INCLUDING WHEN THE SYSTEM COMPLETES AN EXTRATROPICAL
TRANSITION AROUND THE 48 HOUR PERIOD.

THE INITIAL MOTION IS ESTIMATED AT 045/11...SLIGHTLY FASTER.  THE
CYCLONE SHOULD CONTINUE TO GRADUALLY INCREASE IT'S SPEED OF ADVANCE
IN RESPONSE TO AN APPROACHING MID-TROPOSPHERIC TROUGH...WITH
FURTHER INCREASE IN SPEED AS IT MOVES INTO THE UPPER WESTERLY FLOW.
THE LARGE-SCALE MODELS KEEP CRISTOBAL AS A SEPARATE ENTITY DURING
THE NEXT 72 HOURS BEFORE BECOMING ABSORBED BY THE BAROCLINIC ZONE.
A FEW OF THE MODELS ARE SUGGESTING THAT A WEAK SURFACE CIRCULATION
WILL SURVIVE AND DRIFT SOUTHEASTWARD AROUND THE NORTHEAST PERIPHERY
OF THE SUBTROPICAL HIGH...WHICH COULD HAPPEN.  THE OFFICIAL
FORECAST IS A BIT SLOWER THAN THE PREVIOUS FORECAST AND FOLLOWS A
BEND OF THE DYNAMICAL MODELS.

FORECAST POSITIONS AND MAX WINDS

INITIAL      21/0900Z 36.1N  73.9W    45 KT
 12HR VT     21/1800Z 37.2N  72.1W    45 KT
 24HR VT     22/0600Z 39.7N  69.0W    45 KT
 36HR VT     22/1800Z 42.5N  65.0W    45 KT...EXTRATROPICAL
 48HR VT     23/0600Z 44.4N  61.0W    45 KT...EXTRATROPICAL
 72HR VT     24/0600Z 45.0N  52.0W    45 KT...EXTRATROPICAL
 96HR VT     25/0600Z...ABSORBED

$$
FORECASTER ROBERTS/PASCH




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