Tropical Depression FOUR-E

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TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP042008
200 AM PDT WED JUL 02 2008

SATELLITE IMAGES SHOW THAT THE TROPICAL CYCLONE IS SLOWLY BECOMING
BETTER ORGANIZED.  THERE ARE VERY COLD CLOUD TOPS WITHING
DEVELOPING BANDS OVER THE SOUTHERN AND WESTERN PORTIONS OF THE
SYSTEM.  HOWEVER THE BANDS DO NOT YET WRAP SUFFICIENTLY AROUND THE
CENTER TO CLASSIFY THE CYCLONE AS A TROPICAL STORM VIA THE DVORAK
TECHNIQUE.  A QUIKSCAT PASS FROM A FEW HOURS AGO SUGGESTED THAT THE
SYSTEM WAS CLOSE TO TROPICAL STORM INTENSITY EVEN THOUGH AN
AMBIGUITY ANALYSIS OF THE SCATTEROMETER DATA SHOWED A BROAD AND NOT
PARTICULARLY WELL-DEFINED CENTER.  I AM HOLDING OFF ON UPGRADING
FOUR-E ON THIS ADVISORY...BUT SINCE THE CURRENT ENVIRONMENT APPEARS
MODESTLY FAVORABLE WITH WARM WATERS AND MODERATE EASTERLY
SHEAR...THE CYCLONE WILL PROBABLY STRENGTHEN INTO A TROPICAL STORM
TODAY.  WITHIN 36-48 HOURS...THE INTENSITY GUIDANCE IS IN GOOD
AGREEMENT THAT THE SYSTEM WILL BEGIN WEAKENING AS IT NEARS MARGINAL
SEA SURFACE TEMPERATURES.  THIS IS ALSO INDICATED BY THE OFFICIAL
FORECAST...WHICH IS SIMILAR TO THE PREVIOUS ONE AND IN GOOD
AGREEMENT WITH THE SHIPS GUIDANCE.

SINCE THE CENTER IS ILL-DEFINED THERE IS A SOMEWHAT GREATER THAN
USUAL UNCERTAINTY IN THE INITIAL LOCATION AND MOTION.  THE LATTER
IS ESTIMATED TO BE 315/6.  THE DEPRESSION IS ON THE SOUTHERN SIDE OF
A MID-LEVEL RIDGE THAT EXTENDS FROM THE SOUTHWESTERN U.S. INTO
MEXICO.  GLOBAL MODELS SHOW SOME WEAKENING OF THE RIDGE OVER THE
NEXT FEW DAYS.  CONSEQUENTLY THE FORWARD MOTION OF THE TROPICAL
CYCLONE IS LIKELY TO SLOW DURING THE FORECAST PERIOD.  THE OFFICIAL
TRACK FORECAST IS A LITTLE TO THE RIGHT OF THE PREVIOUS NHC
FORECAST AND CLOSE TO A CONSENSUS OF THE GFS...HWRF...GFDL AND U.K.
MET OFFICE FORECAST TRACKS THROUGH 72 HOURS.  AT DAYS 4 AND 5...THE
SYSTEM IS LIKELY TO TURN WESTWARD AS IT WEAKENS AND FOLLOWS THE
LOWER-TROPOSPHERIC FLOW.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/0900Z 16.6N 107.4W    30 KT
 12HR VT     02/1800Z 17.2N 107.9W    35 KT
 24HR VT     03/0600Z 17.9N 108.6W    40 KT
 36HR VT     03/1800Z 18.6N 109.4W    45 KT
 48HR VT     04/0600Z 19.1N 110.1W    40 KT
 72HR VT     05/0600Z 19.8N 111.5W    35 KT
 96HR VT     06/0600Z 20.5N 113.0W    25 KT
120HR VT     07/0600Z 20.5N 114.0W    20 KT...REMNANT LOW
 
$$
FORECASTER PASCH
 
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