Tropical Storm HERNAN

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TROPICAL STORM HERNAN DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092008
800 AM PDT THU AUG 07 2008
 
THE CLOUD PATTERN HAS CONTINUED TO BECOME BETTER ORGANIZED...BUT
NORTHEASTERLY SHEAR IS KEEPING THE CENTER LOCATED IN THE NORTHERN
PORTION OF VERY STRONG CONVECTION.  THE UPPER-LEVEL OUTFLOW IS
WELL-ESTABLISHED EXCEPT TO THE NORTHEAST. THE DVORAK T-NUMBERS HAVE
NOT CHANGED BUT THE CLOUD PATTERN HAS BECOME A LITTLE BETTER
ORGANIZED SINCE THE 12 UTC CLASSIFICATION.  SO...THE INITIAL
INTENSITY IS INCREASED TO 50 KNOTS.  THE SHEAR IS EXPECTED TO RELAX
A LITTLE ALLOWING HERNAN TO STRENGTHEN SOME AND THE CYCLONE COULD
REACH HURRICANE STRENGTH BEFORE IT MOVES OVER COOLER WATERS IN A
COUPLE OF DAYS.   A GRADUAL DECLINE IN STRENGTH IS FORECAST TO
COMMENCE AT THAT TIME.  THE OFFICIAL FORECAST IS A LITTLE BIT
HIGHER THAN GUIDANCE AND FOLLOWS THE PREVIOUS FORECAST. IN
FACT...THE GFDL IS THE ONLY MODEL WHICH BRIEFLY BRINGS HERNAN TO
HURRICANE STATUS.
 
HERNAN IS MOVING TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 10
KNOTS AROUND THE PERIPHERY OF A SUBTROPICAL RIDGE. SINCE THIS
PATTERN IS FORECAST TO PERSIST...THIS GENERAL MOTION IS EXPECTED TO
CONTINUE FOR THE NEXT 2 TO 3 DAYS. THEREAFTER...AS HERNAN WEAKENS
AND BECOMES A SHALLOW SYSTEM...IT SHOULD TURN MORE TO WEST STEERED
BY THE LOW-LEVEL FLOW. THIS OFFICIAL FORECAST IS CLOSE TO THE
DYNAMICAL MODEL CONSENSUS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/1500Z 14.8N 115.1W    50 KT
 12HR VT     08/0000Z 15.4N 116.7W    55 KT
 24HR VT     08/1200Z 16.0N 118.5W    60 KT
 36HR VT     09/0000Z 17.0N 120.0W    65 KT
 48HR VT     09/1200Z 17.5N 122.0W    55 KT
 72HR VT     10/1200Z 18.5N 125.5W    45 KT
 96HR VT     11/1200Z 19.0N 128.5W    35 KT
120HR VT     12/1200Z 19.0N 132.0W    25 KT...REMNANT LOW
 
$$
FORECASTER AVILA
 
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