[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT41 KNHC 312048
TCDAT1
HURRICANE FRANCES DISCUSSION NUMBER  28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT TUE AUG 31 2004

A RECONNAISSANCE PLANE JUST ENTERED THE EYE OF FRANCES. A DROP
MEASURED A MINIMUM PRESSURE OF 940 MB...AND AN EXTRAPOLATED
PRESSURE OF 938 MB WITH A PEAK WIND OF 144 KNOTS AT 700 MB.  THE
STEPPED FREQUENCY MICROWAVE RADIOMETER...SFMR...ON BOARD OF THE
NOAA P-3 PLANE JUST MEASURED 118 KNOTS SURFACE WINDS. HIGH
RESOLUTION SATELLITE IMAGES INDICATE THAT THE CLOUD PATTERN HAS
IMPROVED SINCE THIS MORNING...THE EYE REMAINS LARGE AND DISTINCT
AND THE OUTFLOW IS EXCELLENT IN ALL QUADRANTS. T-NUMBERS HAVE
REACHED 6.5 ON THE DVORAK SCALE. INITIAL INTENSITY HAS BEEN
INCREASED TO 120 KNOTS...MAKING FRANCES A SOLID CATEGORY FOUR ON
THE SAFFIR/SIMPSON HURRICANE SCALE. SINCE THE HURRICANE IS ALREADY
THIS STRONG...SOME FLUCTUATIONS IN INTENSITY ARE EXPECTED DURING
THE NEXT 3 TO 4 DAYS...AND THOSE FLUCTUATIONS WILL BE CONTROLLED IN
PART BY EYEWALL REPLACEMENT CYCLES. WE WILL DESCRIBE THEM AS THEY
OCCUR SINCE THERE IS NO SKILL IN FORECASTING SUCH PROCESSES.
NEVERTHERLESS...FRANCES IS EXPECTED TO REACH THE U.S. COAST AS A
MAJOR HURRICANE.

SATELLITE AND RECONNAISSANCE FIXES INDICATE THAT THE HURRICANE IS
MOVING TOWARD THE WEST OR 280 DEGREES AT 15 KNOTS.  AS INDICATED
PREVIOUSLY... DURING THE THE FIRST 2 TO 3 DAYS...THE HURRICANE WILL
BE MOVING BETWEEN THE WEST AND WEST-NORTHWEST STEERED BY A STRONG
SUBTROPICAL RIDGE. THEREAFTER...THE INTENSITY OF THE RIDGE VARIES
WITH THE DIFFERENT MODELS AND THE FORECAST BECOMES UNCERTAIN.
HOWEVER...ALL MODELS BRING THE HURRICANE TOWARD THE SOUTHEAST COAST
OF THE UNITED STATES IN TRACKS RANGING FROM SOUTHERN FLORIDA
NORTHWARD TO THE CAROLINAS....WITH A GRADUAL DECREASE IN FORWARD
SPEED. THE OFFICIAL FORECAST IS CLOSE TO THE GLOBAL MODEL CONSENSUS
WHICH...IN FACT...HAS SHIFTED SOUTHWARD A LITTLE BIT TAKING INTO
CONSIDERATION THE NEW NOGAPS AND GFDN RUNS. THE FLORIDA STATE
UNIVERSITY SUPERENSEMBLE HAS ALSO SHIFTED A LITTLE BIT SOUTHWARD.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      31/2100Z 20.5N  65.9W   120 KT
 12HR VT     01/0600Z 21.1N  68.2W   125 KT
 24HR VT     01/1800Z 22.5N  71.0W   130 KT
 36HR VT     02/0600Z 23.7N  73.3W   130 KT
 48HR VT     02/1800Z 25.0N  75.5W   130 KT
 72HR VT     03/1800Z 26.6N  78.0W   125 KT
 96HR VT     04/1800Z 29.0N  81.0W   115 KT
120HR VT     05/1800Z 31.1N  82.5W    55 KT...INLAND


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