548 
 WTPZ41 KNHC 251432
 TCDEP1
 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