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Tropical Storm JULIO


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TROPICAL STORM JULIO DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP112008
800 PM PDT SAT AUG 23 2008
 
A SERIES OF MICROWAVE PASSES JUST BEFORE 0000 UTC INDICATES THAT THE
CENTER OF JULIO IS A LITTLE EAST OF THE PREVIOUS TRACK...BUT STILL
NEAR THE EASTERN EDGE OF THE LARGE AREA OF DEEP CONVECTION.  SUCH A
CENTER PLACEMENT SUGGESTS THAT VERTICAL SHEAR CONTINUES TO HINDER
THE DEVELOPMENT OF THE CYCLONE.  IN ADDITION...LATEST DVORAK
INTENSITY ESTIMATES ALONG WITH A COUPLE OF SHIP OBSERVATIONS
SUPPORT KEEPING THE INITIAL INTENSITY AT 35 KT.  WITH JULIO
EXPECTED TO BE OVER SUFFICIENTLY WARM WATER DURING THE NEXT 12-24
HOURS...THE SHORT-TERM INTENSITY FORECAST HINGES ON THE VERTICAL
SHEAR.  UNFORTUNATELY...GLOBAL MODELS ARE NOT IN GOOD AGREEMENT ON
THE FORECAST UPPER-LEVEL PATTERN WITH SOME SHOWING AN INCREASE IN
SHEAR WHILE OTHERS IMPLY SOME DECREASE IN SHEAR.  THE OFFICIAL
FORECAST ASSUMES THAT JULIO WILL ENCOUNTER AN ENVIRONMENT OF
SLIGHTLY WEAKER VERTICAL SHEAR ALLOWING SOME OPPORTUNITY FOR A
LITTLE STRENGTHENING DURING THE NEXT DAY OR SO BEFORE INTERACTION
WITH LAND RESULTS IN WEAKENING. 

BASED ON THE AFOREMENTIONED MICROWAVE PASSES...JULIO IS NOW MOVING 
TOWARD THE NORTH-NORTHWEST OR 335/11.  THE SHORT-TERM TRACK
FORECAST IS A CHALLENGE TO SAY THE LEAST...AS IT IS DIFFICULT TO
ANTICIPATE WHETHER THE CENTER OF JULIO WILL REMAIN CONNECTED WITH
THE DEEP CONVECTION.  SHOULD THE CENTER BECOME DETACHED...IT WOULD
MOVE NORTHWESTWARD WITH THE SHALLOW STEERING.  HOWEVER...IF THE
CENTER REMAINS CONNECTED...IT WOULD TEND TO MOVE MORE NORTH-
NORTHWESTWARD AS SHOWN BY THE GFDL.  THIS RESULTS IN CONSIDERABLE
UNCERTAINTY AS TO WHETHER JULIO WILL TRACK EAST OF...WEST OF...OR
OVER THE BAJA CALIFORNIA PENINSULA.  GIVEN THE GFDL'S RESPECTABLE
TRACK RECORD IN SIMILAR SITUATIONS...THE OFFICIAL FORECAST LEANS
TOWARD THAT MODEL AND IS A LITTLE TO THE RIGHT OF THE DYNAMICAL
MODEL CONSENSUS.  THIS REASONING COUPLED WITH A SLIGHT INITIAL
CENTER RELOCATION NECESSITATES AN EASTWARD SHIFT OF THE OFFICIAL
TRACK FORECAST.  THE NEW FORECAST ALSO REQUIRES A NORTHWARD
EXTENSION OF THE TROPICAL STORM WATCHES AND WARNINGS FOR THE
SOUTHERN BAJA CALIFORNIA PENINSULA.

THE TROPICAL STORM WIND RADII ARE BASED ON NEARBY SHIPS DHER AND
DDFD2

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/0300Z 20.5N 108.6W    35 KT
 12HR VT     24/1200Z 21.8N 109.2W    45 KT
 24HR VT     25/0000Z 23.2N 109.9W    45 KT
 36HR VT     25/1200Z 24.6N 110.6W    40 KT
 48HR VT     26/0000Z 25.7N 111.3W    35 KT
 72HR VT     27/0000Z 27.5N 112.5W    30 KT
 96HR VT     28/0000Z 29.5N 113.0W    25 KT...REMNANT LOW
120HR VT     29/0000Z...DISSIPATED
 
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FORECASTER RHOME
 
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