Hurricane DARBY

ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION DARBY DISCUSSION NUMBER  20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT SAT JUL 31 2004
 
DARBY IS A WEAKENING SWIRL OF LOW CLOUD THAT IS CURRENTLY VOID OF
CENTRAL CONVECTION.  SATELLITE INTENSITY ESTIMATES ARE 25 KT FROM
ALL AGENCIES.  HOWEVER...IN DEFERENCE TO THE QUIKSCAT DATA
MENTIONED IN THE LAST ADVISORY AND WINDS FROM A 0603Z SSM/I
OVERPASS...THE INITIAL INTENSITY WILL BE 30 KT FOR THIS ADVISORY.

THE INITIAL MOTION IS 275/13.  DARBY IS SOUTH OF A STRONG LOW/MID
LEVEL RIDGE...WHICH SHOULD CONTINUE TO STEER THE SYSTEM GENERALLY
WESTWARD DURING THE REMAINDER OF ITS LIFE.  THE FORECAST TRACK IS
AN UPDATE OF THE PREVIOUS PACKAGE FOR THE FIRST 48 HR...THEN
SHIFTED WEST OF THE PREVIOUS PACKAGE FROM 48-96 HR.

WHILE DARBY SHOULD BE MOVING OVER WARMER WATER FROM HERE ON...
SATELLITE IMAGERY AND LARGE SCALE MODELS INDICATE STRONG
SOUTHWESTERLY VERTICAL SHEAR DEVELOPING OVER THE CYCLONE THROUGH
THE FORECAST PERIOD.  THIS SHOULD CONTINUE THE CURRENT WEAKENING
TREND...WITH DARBY BECOMING A REMNANT LOW IN 36-48 HR AND WEAKENING
TO AN EASTERLY WAVE AFTER 96 HR.  DARBY MAY DISSIPATE EVEN FASTER
THAN CURRENTLY FORECAST.

FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      31/1500Z 18.9N 138.0W    30 KT
 12HR VT     01/0000Z 19.0N 140.1W    25 KT
 24HR VT     01/1200Z 19.0N 143.3W    25 KT
 36HR VT     02/0000Z 19.0N 146.6W    25 KT...DISSIPATING
 48HR VT     02/1200Z 19.0N 149.5W    20 KT...REMNANT LOW
 72HR VT     03/1200Z 19.5N 154.5W    20 KT...REMNANT LOW
 96HR VT     04/1200Z 20.5N 158.0W    20 KT...REMNANT LOW
120HR VT     05/1200Z...DISSIPATED
 
 
$$
NNNN