Hurricane DARBY
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HURRICANE DARBY DISCUSSION NUMBER 12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
200 PM PDT FRI JUN 25 2010
DARBY REMAINS A WELL-ORGANIZED HURRICANE WITH VISIBLE IMAGERY
SHOWING A DISTINCT EYE AND AN IMPRESSIVE OUTFLOW PATTERN. DVORAK
SATELLITE CLASSIFICATIONS FROM TAFB AND SAB AT 1800 UTC WERE
T5.5...102 KT. SINCE THAT TIME...THE SYSTEM HAS BECOME BETTER
ORGANIZED WITH DEEPER CONVECTION IN THE EYEWALL. THUS...THE INITIAL
INTENSITY IS NUDGED UPWARD TO 105 KT. EASTERLY SHEAR IS FORECAST
BY ALL OF THE GLOBAL MODELS TO INCREASE OVERNIGHT WHICH SHOULD
LIMIT FUTURE STRENGTHENING. THIS SHEAR WILL LIKELY PERSIST FOR
SEVERAL DAYS AND CAUSE DARBY TO GRADUALLY WEAKEN. MOST OF THE
INTENSITY GUIDANCE IS IN REASONABLE AGREEMENT ON THIS SCENARIO...
AND THE NHC FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS
ADVISORY.
THE INITIAL MOTION OF THE TROPICAL CYCLONE IS TOWARD THE
WEST-NORTHWEST OR 285/5. A MID-TROPOSPHERIC RIDGE OVER MEXICO IS
FORECAST BY ALL OF THE GLOBAL MODELS TO WEAKEN DURING THE NEXT 24
HOURS...WHICH SHOULD CAUSE DARBY TO SLOW DOWN AND BECOME NEARLY
STATIONARY. THEREAFTER...THE MODELS HAVE WILDLY DIVERGENT
SOLUTIONS...WITH THE HWRF CONTINUING A WESTWARD MOTION OF DARBY AND
THE ECMWF/UKMET SHOWING AN EASTWARD MOTION. MOST OF THIS
DISAGREEMENT IS CAUSED BY THE HANDLING OF THE SYSTEM OVER THE
NORTHWESTERN CARIBBEAN...AND WHETHER THE MUCH-SMALLER DARBY GETS
CAUGHT UP IN WESTERLY FLOW SOUTH OF MEXICO. IT IS BEST TO STAY
CLOSE TO THE MODEL CONSENSUS FOR NOW...AND THE NHC FORECAST IS
CLOSE TO THE PREVIOUS ONE...A LITTLE WEST OF THE DYNAMICAL MODEL
CONSENSUS.
DARBY IS THE EARLIEST SECOND MAJOR HURRICANE FORMATION IN THE
EASTERN PACIFIC SINCE RELIABLE RECORDS BEGAN IN 1971...ECLIPSING OF
THE PREVIOUS RECORD OF HURRICANE DANIEL ON JUNE 30 1978.
FORECAST POSITIONS AND MAX WINDS
INITIAL 25/2100Z 13.6N 101.5W 105 KT
12HR VT 26/0600Z 13.7N 102.3W 105 KT
24HR VT 26/1800Z 13.5N 103.3W 100 KT
36HR VT 27/0600Z 13.4N 103.8W 90 KT
48HR VT 27/1800Z 13.5N 104.2W 80 KT
72HR VT 28/1800Z 14.0N 103.5W 65 KT
96HR VT 29/1800Z 14.3N 102.7W 55 KT
120HR VT 30/1800Z 14.6N 102.0W 45 KT
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FORECASTER BLAKE
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