000
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

000
WTNT41 KNHC 291432
TCDAT1

TROPICAL DEPRESSION ELEVEN DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112013
1100 AM AST SUN SEP 29 2013

THE DEPRESSION HAS A POORLY ORGANIZED PRESENTATION ON SATELLITE
IMAGES THIS MORNING.  THE LOW-LEVEL CENTER IS NOT WELL DEFINED AND
DEEP CONVECTION IS LIMITED TO A FEW CLUSTERS OF SHOWERS AND
THUNDERSTORMS OVER THE NORTHERN SEMICIRCLE AND A NARROW BAND OVER
THE EASTERN PORTION OF THE CIRCULATION.  DVORAK CLASSIFICATIONS
SUPPORT AN INTENSITY OF NO MORE THAN 25-30 KT...SO THE CURRENT
INTENSITY IS HELD AT 30 KT.  AN UPPER-LEVEL LOW JUST TO THE
NORTHWEST OF THE DEPRESSION CONTINUES TO IMPART SOUTHWESTERLY
SHEAR...AND THE GLOBAL MODELS SUGGEST THAT THIS REGIME SHOULD
CONTINUE FOR THE NEXT 12-24 HOURS.  LATER ON...THE DYNAMICAL
GUIDANCE INDICATES SOME RELAXATION OF THE SHEAR SO SOME
STRENGTHENING IS FORECAST IN A DAY OR SO.  THE LATEST GFS RUN DOES
NOT SHOW THE SYSTEM WEAKENING IN THE LATTER PART OF THE FORECAST
PERIOD...AND THE NEW OFFICIAL FORECAST CALLS FOR THE CYCLONE TO
MAINTAIN ITSELF FOR THE NEXT 5 DAYS. THIS IS VERY CLOSE TO THE
LATEST INTENSITY MODEL CONSENSUS.

THERE IS CONSIDERABLE SPREAD IN CENTER FIXES...AND THE INITIAL
MOTION IS AN UNCERTAIN 050/8.  A MID-LEVEL RIDGE IS PREDICTED BY
THE GLOBAL MODELS TO AMPLIFY TO THE WEST OF THE CYCLONE WITHIN THE
NEXT COUPLE OF DAYS...WHICH SHOULD CAUSE THE SYSTEM TO SLOW DOWN AND
TURN TOWARD THE RIGHT.  THE GFS AND ECMWF GLOBAL MODELS AS WELL AS
THE HFIP STREAM 1.5 MODEL CONSENSUS SHOW THE TROPICAL CYCLONE
EXECUTING A SMALL CLOCKWISE LOOP DURING THE NEXT FEW DAYS...AND SO
DOES THE OFFICIAL TRACK FORECAST.  BY LATE IN THE FORECAST
PERIOD...A LARGE MID-LEVEL TROUGH APPROACHING FROM THE WEST SHOULD
CAUSE THE CYCLONE TO MOVE NORTHEASTWARD.  THE NEW NHC TRACK
FORECAST IS SIMILAR TO THE PREVIOUS ONE...ALBEIT SHIFTED SLIGHTLY
EASTWARD.

FORECAST POSITIONS AND MAX WINDS

INIT  29/1500Z 26.0N  48.6W   30 KT  35 MPH
 12H  30/0000Z 26.7N  47.7W   30 KT  35 MPH
 24H  30/1200Z 26.8N  46.8W   35 KT  40 MPH
 36H  01/0000Z 26.5N  46.3W   40 KT  45 MPH
 48H  01/1200Z 26.5N  47.0W   40 KT  45 MPH
 72H  02/1200Z 26.5N  47.5W   40 KT  45 MPH
 96H  03/1200Z 27.5N  47.5W   40 KT  45 MPH
120H  04/1200Z 29.5N  45.0W   40 KT  45 MPH

$$
FORECASTER PASCH

Pedro C. Fernández ‏@PedroCFernandez 30s

Interacción #JERRY con #vaguada polar, #humedad ya por #Azores