Tropical Storm EMILIA

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TROPICAL STORM EMILIA DISCUSSION NUMBER  17
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP062006
800 AM PDT TUE JUL 25 2006
 
SATELLITE IMAGERY INDICATES THAT EMILIA HAS STRENGTHENED WITH
INCREASING CONVECTION SEEN OVER THE SOUTHERN SEMICIRCLE.  THE
INITIAL INTENSITY IS INCREASED TO 55 KT IN AGREEMENT WITH SATELLITE
INTENSITY ESTIMATES FROM BOTH SAB AND TAFB.  DESPITE THE RECENT
ORGANIZATION...EMILIA'S OPPORTUNITY FOR STRENGTHENING APPEARS SMALL
AS THE CYCLONE MOVES INTO PROGRESSIVELY COOLER WATER AND A MORE
STABLE AIRMASS.  THE OFFICIAL FORECAST SHOWS A LITTLE MORE
STRENGTHENING THROUGH 12 HOURS WITH WEAKENING INDICATED THEREAFTER.  
 
EMILIA IS LOCATED WITHIN A LARGE LOWER TO MID LEVEL CYCLONIC
CIRCULATION IN BETWEEN A DEEP LAYER RIDGE OVER THE SOUTHWEST U.S.
AND A SECOND RIDGE EXTENDING ACROSS SOUTHERN MEXICO AND NORTHERN
CENTRAL AMERICA. THIS PATTERN HAS RESULTED IN A NORTHWESTWARD
MOTION WHICH MANY OF THE DYNAMICAL MODELS HAVE NOT HANDLED WELL.
MOST OF THE GUIDANCE CONTINUE AN OVERALL NORTHWEST MOTION THROUGH 36
HOURS.  THEREAFTER...THE GFDL AGAIN TURNS THE CYCLONE NORTHWARDS
WHILE THE GFS-BASED BAM MODELS TURN THE CYCLONE WESTWARD.  GIVEN
THE RECENT PERFORMANCE OF THE DYNAMICAL MODELS...THE OFFICIAL
FORECAST IS ESSENTIALLY UNCHANGED AND ALONG THE FAR RIGHT SIDE OF
THE GUIDANCE SUITE THROUGH 24 HOURS.  SUBSEQUENTLY...A GRADUAL TURN
MORE TOWARDS THE WEST IS SHOWN UNDER THE ASSUMPTION THAT AN
INCREASINGLY SHALLOW SYSTEM WILL BE STEERED BY THE LOWER LEVEL
EASTERLIES.  ONE CAVEAT IS THAT THE GLOBAL MODELS SUGGEST THAT
EMILIA COULD BE TOO FAR EAST FOR THE LOW LEVEL RIDGING TO TURN IT
WESTWARD.  GIVEN THE SPREAD OF THE GUIDANCE AT THE LATER STAGES OF
THE FORECAST...A SLOW WESTWARD MOTION IS SHOWN.  
 
NEARBY SHIP OBSERVATIONS AND SSM/I DERIVED OCEAN WINDS REQUIRE AN
EXPANSION OF THE WIND RADII OVER THE NORTHEASTERN QUADRANT.  THIS
CHANGE NOW WARRANTS THE ISSUANCE OF A TROPICAL STORM WATCH FOR
SOUTHERN PORTIONS OF THE BAJA PENINSULA. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      25/1500Z 20.6N 111.3W    55 KT
 12HR VT     26/0000Z 21.8N 112.3W    60 KT
 24HR VT     26/1200Z 23.3N 114.0W    50 KT
 36HR VT     27/0000Z 24.3N 115.5W    40 KT
 48HR VT     27/1200Z 25.2N 116.8W    30 KT...DISSIPATING
 72HR VT     28/1200Z 25.8N 119.6W    25 KT...REMNANT LOW
 96HR VT     29/1200Z...DISSIPATED
 
$$
FORECASTER RHOME/BEVEN
 
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