238 
 WTPZ41 KNHC 290851
 TCDEP1
 TROPICAL STORM ALETTA DISCUSSION NUMBER   9
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP012006
 200 AM PDT MON MAY 29 2006
  
 MICROWAVE SATELLITE IMAGERY AROUND 03Z INDICATED THE CENTER OF 
 ALETTA HAD REMAINED WELL-DEFINED AS THE CYCLONE CONTINUED TO
 DRIFT SLOWLY NORTHWARD. HOWEVER...SINCE THE LAST MICROWAVE
 OVERPASS... INFRARED SATELLITE IMAGERY INDICATES DEEP CONVECTION 
 AND POSSIBLY A SMALL CDO HAVE DEVELOPED OVER THE LOW-LEVEL CENTER.
 THE INITIAL INTENSITY OF 40 KT IS BASED ON A BLEND OF SATELLITE
 ESTIMATES OF 35 KT FROM TAFB AND SAB...45 KT FROM AFWA...AND THE
 RECENT DEVELOPMENT OF THE CDO-LIKE CONVECTIVE FEATURE.
  
 THE INITIAL MOTION ESTIMATE REMAINS 360/02 KT...BASED ON MICROWAVE
 POSITION ESTIMATES BETWEEN 00Z AND 03Z. ALL OF THE NHC MODEL 
 GUIDANCE SUGGESTS THAT A GRADUAL TURN TOWARD THE NORTHWEST OR
 WEST-NORTHWEST SHOULD OCCUR WITHIN THE NEXT 24 HOURS AS MID-LEVEL
 RIDGING TO THE NORTH AND NORTHWEST OF ALETTA SLOWLY DEVELOPS
 EASTWARD. THE MODELS ARE IN EXCELLENT AGREEMENT ON THIS EVOLVING
 SCENARIO...AND THE ONLY DIFFERENCE BETWEEN THE MODELS LIES IN HOW
 FAST THEY MOVE ALETTA WESTWARD AFTER 72 HOURS. THE UKMET APPEARS TO
 BE TOO FAST IN THE LATTER PERIODS...WHICH HAS CONTAMINATED THE GUNA
 AND GUNS CONSENSUS FORECASTS. AS A RESULT...THE OFFICIAL FORECAST IS
 SLOWER THAN GUNA AND IS SIMILAR TO THE PREVIOUS FORECAST TRACK.
 
 THE MUCH ADVERTISED DECREASE IN THE VERTICAL SHEAR OVER THE PAST
 COUPLE OF DAYS FINALLY APPEARS TO BE OCCURRING. UPPER-LEVEL OUTFLOW
 HAS IMPROVED TO THE WEST...AND THE DEVELOPMENT OF THE CDO-LIKE
 FEATURE COULD BE THE ONSET OF MORE SIGNIFICANT INTENSIFICATION...
 MAINLY IN THE SHORT TERM. THE SHIPS MODEL DECREASES THE VERTICAL
 SHEAR TO ABOUT 5 KT BY 24 HOURS...AND THEN GRADUALLY INCREASES THE
 WEST TO SOUTHWESTERLY SHEAR TO 20-25 BY 48 HOURS AND BEYOND.
 THEREFORE... THE INTENSIFICATION TREND WAS INCREASED A LITTLE BIT
 ABOVE THE SHIPS MODEL FORECASTS THROUGH 48 HOURS...AND THEN IS CLOSE
 TO THE SHIPS INTENSITY FORECASTS AFTER THAT.
  
 FORECASTER STEWART
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      29/0900Z 16.2N 101.0W    40 KT
  12HR VT     29/1800Z 16.4N 101.2W    45 KT
  24HR VT     30/0600Z 16.4N 102.0W    50 KT
  36HR VT     30/1800Z 16.4N 102.7W    55 KT
  48HR VT     31/0600Z 16.4N 103.4W    55 KT
  72HR VT     01/0600Z 16.3N 104.7W    50 KT
  96HR VT     02/0600Z 16.0N 106.0W    50 KT
 120HR VT     03/0600Z 16.0N 107.5W    45 KT
  
 $$