Tropical Storm PATRICIA

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TROPICAL STORM PATRICIA DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP192009
800 PM PDT SUN OCT 11 2009
 
LAST-LIGHT VISIBLE IMAGERY SHOWED THAT THE WELL-DEFINED CENTER OF
THE TROPICAL CYCLONE BECAME MORE EMBEDDED WITHIN THE VERY COLD
CLOUD TOPS THAN IT WAS EARLIER TODAY.  BASED UPON INCREASED
ORGANIZATION OF THE DEEP CONVECTION OVER THE PAST SEVERAL HOURS AND
CONSENSUS T2.5 DVORAK CLASSIFICATIONS FROM TAFB AND SAB...THE
SYSTEM IS UPGRADED TO A 35-KT TROPICAL STORM.  TROPICAL STORM
PATRICIA IS THE 16TH NAMED CYCLONE OF THIS RELATIVELY BUSY EASTERN
NORTH PACIFIC SEASON.

A 2055Z AQUA MICROWAVE PASS ALONG WITH THE LAST FEW VISIBLE
GEOSTATIONARY IMAGES ALLOWS FOR A MODERATELY CONFIDENT INITIAL
MOTION ESTIMATE OF 350/06.  THE CYCLONE IS BEING STEERED BY A DEEP-
LAYERED RIDGE TO ITS EAST AND A MID- TO UPPER-LEVEL TROUGH TO ITS
NORTHWEST.  A NORTH TO NORTH-NORTHWESTWARD MOTION OF PATRICIA
SHOULD CONTINUE THROUGH 48 HOURS.  THEREAFTER THE CYCLONE IS
PROJECTED TO TURN MORE WESTWARD AS THE TROUGH LIFTS OUT AND THE
RIDGE BUILDS IN TO THE NORTH OF THE TROPICAL CYCLONE.  AT THE
LONGER RANGE...THE GLOBAL MODELS TEND TO LEAVE A WEAKENING VORTEX
IN THE VICINITY OF SOUTHERN BAJA CALIFORNIA OR SOUTHERN GULF OF
CALIFORNIA...WHILE THE REGIONAL HURRICANE MODELS MAINTAIN A
STRONGER SYSTEM AND ADVECT IT AWAY FROM THE BAJA PENINSULA.  THE
OFFICIAL FORECAST LEANS MORE TOWARD THE LATTER SCENARIO AND IS A
BLEND OF THE MODEL CONSENSUS AND THE PREVIOUS NHC FORECAST.

PATRICIA HAS TWO...PERHAPS THREE...DAYS OF LOW VERTICAL SHEAR BEFORE
IT MOVES NORTH OF THE UPPER-LEVEL RIDGE AND BEGINS TO ENCOUNTER 
STRONGER SOUTHWESTERLY WINDS ALOFT.  CONVERSELY...THE
THERMODYNAMICS ARE MORE MIXED WITH QUITE WARM SSTS ALONG THE
CYCLONE'S PROJECTED TRACK...BUT FAIRLY STABLE ATMOSPHERIC
CONDITIONS ANTICIPATED BY THE SHIPS MODEL.  THE STATISTICAL LGEM
AND SHIPS MODELS PEAK PATRICIA NEAR 50 KT AT 48 TO 72 HOURS...WHILE
THE DYNAMICAL HWRF AND GFDL MODELS SHOW A MUCH STRONGER CYCLONE. 
THE OFFICIAL INTENSITY FORECAST IS CLOSE TO LGEM/SHIPS...BUT DOES
INDICATE A MORE INTENSE TROPICAL STORM THAN THE PREVIOUS NHC
FORECAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0300Z 17.9N 108.5W    35 KT
 12HR VT     12/1200Z 18.9N 108.7W    40 KT
 24HR VT     13/0000Z 20.1N 109.0W    45 KT
 36HR VT     13/1200Z 21.1N 109.2W    50 KT
 48HR VT     14/0000Z 21.8N 109.6W    50 KT
 72HR VT     15/0000Z 22.5N 111.0W    45 KT
 96HR VT     16/0000Z 23.0N 113.0W    35 KT
120HR VT     17/0000Z 23.0N 116.0W    25 KT...REMNANT LOW
 
$$
FORECASTER LANDSEA/PASCH
 
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