000
WTNT42 KNHC 091435
TCDAT2
HURRICANE OTTO DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL172010
1100 AM AST SAT OCT 09 2010

THE CLOUD PATTERN ASSOCIATED WITH OTTO HAS GRADUALLY BEEN DECREASING
IN ORGANIZATION DURING THE LAST SEVERAL HOURS.  THE CENTRAL DENSE
OVERCAST THAT THE CYCLONE HAD BEEN MAINTAINING HAS BECOME
INCREASINGLY DISTORTED...AND CONVECTIVE CLOUD TOPS HAVE WARMED.  A
SERIES OF MICROWAVE OVERPASSES SUGGEST THAT THE CENTER IS LOCATED
ON THE SOUTHWEST SIDE OF THE DEEPEST CONVECTION...AND GIVE EVIDENCE
OF A PRONOUNCED TILT OF THE VORTEX DUE TO THE EFFECT OF MODERATE
SOUTHWESTERLY SHEAR.  THE INITIAL INTENSITY IS LOWERED TO 65 KT
BASED UPON DVORAK T-NUMBERS OF 3.5 AND 4.0 FROM SAB AND TAFB...
RESPECTIVELY.  FURTHER WEAKENING IS LIKELY OVER THE NEXT SEVERAL
DAYS AS OTTO ENTERS A STRONGLY SHEARED ENVIRONMENT AND MOVES OVER
PROGRESSIVELY COOLER WATERS.  GLOBAL MODELS SUGGEST THAT
EXTRATROPICAL TRANSITION MAY HAVE ALREADY BEGUN...AND THE COMPLETION
OF THIS PROCESS...ALTHOUGH STILL A BIT UNCERTAIN...IS FORECAST BY
ABOUT 48 HOURS.  THE OFFICIAL INTENSITY FORECAST IS ADJUSTED
DOWNWARD BASED UPON RECENT TRENDS AND IS IN GOOD AGREEMENT
WITH THE STATISTICAL-DYNAMICAL GUIDANCE.

THE MICROWAVE FIXES WERE HELPFUL IN FINDING THE CENTER OF OTTO AND
SUGGEST THAT THE HURRICANE HAS CONTINUED TO ACCELERATE...WITH AN
INITIAL MOTION ESTIMATE OF 055/25.  OTTO IS FORECAST TO ACCELERATE
FURTHER ON A GENERALLY NORTHEASTWARD COURSE DURING THE NEXT 24-36
HOURS IN BETWEEN A LARGE DEEP-LAYER TROUGH OVER THE NORTHWEST
ATLANTIC AND A SUBTROPICAL RIDGE TO ITS EAST.  ONCE POST-
TROPICAL...OTTO IS EXPECTED TO ABRUPTLY DECELERATE AND TURN
EASTWARD AND SOUTHEASTWARD AS IT ROUNDS THE TOP OF A SHORTWAVE
RIDGE AND DIVES INTO THE WEST SIDE OF A TROUGH OVER THE NORTHEAST
ATLANTIC.  ALTHOUGH THE MODEL GUIDANCE CONTINUES TO HAVE DIFFICULTY
IN PREDICTING THE SHARPNESS OF THIS TURN...THE SPREAD IN THE MODEL
SOLUTIONS HAS DECREASED SOME SINCE THE LAST CYCLE.  THE OFFICIAL
TRACK FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE AND IS
CLOSE TO THE MULTI-MODEL CONSENSUS.


FORECAST POSITIONS AND MAX WINDS

INITIAL      09/1500Z 30.7N  55.7W    65 KT
 12HR VT     10/0000Z 32.9N  51.4W    60 KT
 24HR VT     10/1200Z 36.2N  44.2W    55 KT
 36HR VT     11/0000Z 39.7N  36.7W    50 KT
 48HR VT     11/1200Z 42.5N  31.0W    45 KT...POST-TROP/EXTRATROP
 72HR VT     12/1200Z 43.0N  26.0W    35 KT...POST-TROP/EXTRATROP
 96HR VT     13/1200Z 39.6N  24.0W    30 KT...POST-TROP/EXTRATROP
120HR VT     14/1200Z 36.5N  21.5W    30 KT...POST-TROP/EXTRATROP

$$
FORECASTER KIMBERLAIN