[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 231459
TCDAT1
TROPICAL STORM FRANKLIN DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT SAT JUL 23 2005

RECENT REPORTS FROM AN AIR FORCE RECON AIRCRAFT INDICATE FRANKLIN
HAS BECOME MUCH BETTER ORGANIZED AND HAS STRENGTHENED...POSSIBLY
EVEN TO HURRICANE STRENGTH. A DROPSONDE REPORT AT 1337Z MEASURED
SURFACE WINDS OF 59 KT IN THE SOUTHEAST QUADRANT WHERE THE FLIGHT
CREW HAS BEEN ESTIMATING 60-65 KT WINDS...EVEN THOUGH THE CENTRAL
PRESSURE IS STILL ABOVE 1000 MB. THE INITIAL INTENSITY IS BEING
INCREASED TO 60 KT FOR THIS ADVISORY...BUT THE INTENSITY COULD BE
HIGHER SINCE FRANKLIN IS EMBEDDED IN A REGION OF MUCH HIGHER THAN
AVERAGE SURFACE PRESSURES.

THE INITIAL MOTION ESTIMATE IS 055/08...BASED ON THE PAST 9 HOURS OF
RECON FIXES. THE CENTER OF FRANKLIN IS LOCATED NEAR THE NORTHWEST
PORTION OF THE COLD CDO CLOUD SHIELD AND IS SHOWING SIGNS OF
BECOMING BETTER ORGANIZED IN SATELLITE IMAGERY THAN WHAT MOST OF
THE GLOBAL MODELS HAVE BEEN INDICATING. THE STRONG SHORTWAVE NOW
APPROACHING THE U.S. EAST COAST HAS MOST OF ITS ENERGY FROM NORTH
CAROLINA NORTHWARD...WITH ONLY 5-10 WEST-NORTHWESTERLY MID-LEVEL
FLOW INDICATED SOUTH OF THE CAROLINAS. MOST OF THE MODEL GUIDANCE
...EXCLUDING THE MUCH FASTER GFS AND GFDL MODELS...NOW SLOWS DOWN
FRANKLIN THROUGH 72 HOURS AND EITHER DISSIPATED THE CYCLONE OR
WAITS FOR ANOTHER SHORTWAVE TROUGH TO PICK UP THE CYCLONE AND
ACCELERATE IT QUICKLY TO THE NORTHEAST. JUST ONE PROBLEM...ALL OF
THE MODELS...TO SOME DEGREE...MOVE THE MID-LEVEL CIRCULATION SLOWLY
BACK TO THE SOUTH AND SOUTHWEST AFTER 72 HOURS. THIS SCENARIO IS
SIMILAR TO THE MEDIUM AND DEEP BAM MODELS. GIVEN THAT FRANKLIN IS
CURRENTLY SOUTH OF AND SLOWER THAN ALL OF THE NHC MODEL GUIDANCE
FROM 06Z...AND THAT ALL OF THE MODELS FORECAST THE MID-LEVEL FLOW
TO BECOME NORTHWEST TO NORTHERLY BY 72 HOURS...THE OFFICIAL TRACK
HAS BEEN SHIFTED TO THE RIGHT...OR SOUTH...OF AND A LITTLE SLOWER
THAN THE PREVIOUS FORECAST. THIS TRACK IS CONSISTENT WITH THE GUNS
MODEL CONSENSUS.

FRANKLIN REMAINS RELATIVELY SMALL TROPICAL CYCLONE...BUT WITH A
WELL-DEFINED INNER CORE WIND FIELD. AS SUCH...SMALL CHANGES IN THE
CENTRAL DEEP CONVECTION CAN RESULT IN SIGNIFICANT CHANGES IN
INTENSITY. GIVEN THE TENACITY OF THIS CYCLONE OVER THE PAST FEW
DAYS THAT HAS DEFIED FAIRLY SIGNIFICANT VERTICAL SHEAR...IT APPEARS
THAT THIS SYSTEM WILL PROBABLY GO ON AND BECOME A HURRICANE WITH A
CENTRAL PRESSURE ABOVE 995 MB IN THE NEXT 12-24 HOURS. AFTER
THAT...INCRESING NORTHWEST TO NORTHWESTERLY MID- TO UPPER-LEVEL
FLOW SHOULD INDUCE SOME SLOW WEAKENING.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL      23/1500Z 29.4N  75.0W    60 KT
 12HR VT     24/0000Z 30.1N  73.8W    65 KT
 24HR VT     24/1200Z 30.7N  72.1W    65 KT
 36HR VT     25/0000Z 31.1N  70.4W    60 KT
 48HR VT     25/1200Z 31.5N  68.7W    55 KT
 72HR VT     26/1200Z 32.3N  66.0W    50 KT
 96HR VT     27/1200Z 33.0N  63.5W    45 KT
120HR VT     28/1200Z 35.0N  59.0W    40 KT

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