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 507 
 WTNT41 KNHC 290847
 TCDAT1
  
 TROPICAL DEPRESSION ELEVEN DISCUSSION NUMBER   2
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112013
 500 AM AST SUN SEP 29 2013
  
 NIGHTTIME VISIBLE IMAGERY INDICATES THE DEPRESSION HAS A ROBUST
 LOW-LEVEL CIRCULATION...BUT THE ASSOCIATED DEEP CONVECTION IS
 SHEARED WELL TO THE NORTH AND NORTHEAST OF THE CENTER. SOME WEAK
 CURVED BAND FEATURES HAVE DEVELOPED RECENTLY IN THE EASTERN
 SEMICIRCLE...SUGGESTING THAT THE SYSTEM IS TRYING TO GET BETTER
 ORGANIZED. FOR NOW...HOWEVER...AN INTENSITY OF 30 KT IS BEING
 MAINTAINED BASED ON A SATELLITE INTENSITY ESTIMATE OF 30 KT FROM
 TAFB AND UW-CIMSS ADT.
  
 THE INITIAL MOTION ESTIMATE IS 040/08 KT. THERE IS NO SIGNIFICANT
 CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. THE SMALL
 DEPRESSION IS EXPECTED TO MOVE NORTHEASTWARD AND SLOW DOWN AS IT
 MOVES AROUND THE NORTH SIDE OF A WEAKENING MID-LEVEL RIDGE WHILE A
 SHORTWAVE TROUGH TO THE NORTH GRADUALLY LIFTS OUT. THIS SHOULD
 RESULT IN VERY WEAK STEERING FLOW FOR THE NEXT COUPLE OF DAYS. A
 NEW RIDGE IS THEN FORECAST BY THE MODELS TO BUILD IN AND BECOME
 HIGHLY AMPLIFIED TO THE WEST AND NORTH OF THE CYCLONE BY 48
 HOURS...WHICH SHOULD ACT TO TURN THE CYCLONE WESTWARD THROUGH 72
 HOURS...COMPLETING A SMALL CLOCKWISE LOOP IN THE PROCESS. AFTER
 THAT...A SECOND AND STRONGER MID-/UPPER-LEVEL TROUGH WILL MOVE
 EASTWARD FROM THE UNITED STATES...AND ACT TO LIFT OUT THE CYCLONE
 AND ACCELERATE IT TO THE NORTHEAST ON DAYS 4 AND 5. THE NEW NHC
 FORECAST TRACK IS ALMOST IDENTICAL TO THE PREVIOUS TRACK...AND LIES
 CLOSE TO A BLEND OF THE GFS AND ECMWF MODELS.
  
 ALTHOUGH THE GFS-BASED SHIPS INTENSITY MODEL IS ONLY INDICATING 9 KT
 OF SOUTH-SOUTHWESTERLY VERTICAL SHEAR ACROSS THE DEPRESSION...WHICH
 IS SIGNIFICANTLY LOWER THAN IT WAS ON THE PREVIOUS ADVISORY...
 SATELLITE IMAGERY AND THE ASSOCIATED CONVECTIVE CLOUD PATTERN OF
 THE DEPRESSION SUGGESTS THAT THE SHEAR IS CONSIDERABLY STRONGER...
 LIKELY DUE TO THE PRESENCE OF A MID-/UPPER-LEVEL LOW LOCATED ONLY
 ABOUT 300 NMI TO THE NORTHWEST OF THE CYCLONE. THAT LOW IS FORECAST
 BY MOST OF THE MODELS...ESPECIALLY THE GFS AND ECMWF...TO MOVE IN
 TANDEM WITH THE CYCLONE OVER THE NEXT 72 HOURS OR SO AS IT MAKES A
 CLOCKWISE LOOP. AS A RESULT...THIS SYSTEM WILL LIKELY BE PLAGUED BY
 AT LEAST MODERATE SHEAR FOR THE NEXT 2 TO 3 DAYS...WHICH SHOULD
 PREVENT ANY SIGNIFICANT STRENGTHENING FROM OCCURRING. THE NHC
 INTENSITY FORECAST IS IDENTICAL TO THE PREVIOUS PACKAGE AND REMAINS
 CLOSE TO THE INTENSITY CONSENSUS MODEL...ICON. HOWEVER...IF THE
 AFOREMENTIONED UPPER-LEVEL SHOULD DISSIPATE OR MOVE AWAY FROM THE
 CYCLONE SOONER THAN CURRENTLY EXPECTED...THEN THE SYSTEM COULD BE
 SOMEWHAT STRONGER THAN CURRENTLY FORECAST ON DAYS 4 AND 5.  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  29/0900Z 25.6N  49.7W   30 KT  35 MPH
  12H  29/1800Z 26.4N  48.8W   35 KT  40 MPH
  24H  30/0600Z 27.0N  47.6W   40 KT  45 MPH
  36H  30/1800Z 26.8N  46.8W   40 KT  45 MPH
  48H  01/0600Z 26.4N  46.6W   40 KT  45 MPH
  72H  02/0600Z 26.3N  47.8W   35 KT  40 MPH
  96H  03/0600Z 27.7N  48.6W   35 KT  40 MPH
 120H  04/0600Z 30.0N  47.0W   30 KT  35 MPH
  
 $$
 FORECASTER STEWART
  
 
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