WTNT44 KNHC 281443
TCDAT4
TROPICAL DEPRESSION FOURTEEN DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL142007
1100 AM EDT FRI SEP 28 2007
 
SATELLITE IMAGES...MICROWAVE DATA AND SHIP OBSERVATIONS INDICATE
THAT THE AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE NEAR
THE CAPE VERDE ISLANDS HAS DEVELOPED INTO A TROPICAL DEPRESSION.
THE CYCLONE HAS DEEP ORGANIZED CONVECTION NEAR THE CENTER WITH WELL
ESTABLISHED OUTFLOW. A SHIP LOCATED JUST TO THE NORTH OF THE CENTER
REPORTED 29 KNOTS. BASED ON THE ABOVE INFORMATION...THE INITIAL
INTENSITY IS SET AT 30 KNOTS. THE DEPRESSION HAS THE OPPORTUNITY TO
STRENGTHEN A LITTLE DURING THE NEXT DAY OR TWO...WHILE THE SHEAR IS
LOW.  

THE DEPRESSION IS LOCATED TO THE SOUTHEAST OF A RATHER STRONG
MID-LEVEL TROUGH AND ON THE WESTERN EDGE OF A MID-LEVEL RIDGE. THIS
PATTERN WOULD FAVOR A GRADUAL TURN TOWARD THE NORTHWEST AND NORTH
THROUGH THE FORECAST PERIOD. ON THIS TRACK...THE CYCLONE SHOULD
ENCOUNTER HIGHER SHEAR AND COOLER WATERS BEYOND 48 HOURS. THIS
SHOULD RESULT IN WEAKENING. THE OFFICIAL INTENSITY FORECAST IS MUCH
LOWER THAN THE SHIPS MODEL WHICH IN FACT MAKES THE DEPRESSION A
HURRICANE IN ABOUT 2 DAYS. 

NUMERICAL GUIDANCE IS LIMITED AT THIS TIME BUT WE SHOULD HAVE MORE
INFORMATION FROM GLOBAL MODELS AFTER THE 12Z RUN. 

  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/1500Z 14.1N  26.5W    30 KT
 12HR VT     29/0000Z 14.4N  27.3W    35 KT
 24HR VT     29/1200Z 15.0N  28.5W    40 KT
 36HR VT     30/0000Z 16.0N  30.0W    40 KT
 48HR VT     30/1200Z 17.0N  31.5W    35 KT
 72HR VT     01/1200Z 18.5N  34.0W    30 KT
 96HR VT     02/1200Z 21.0N  36.0W    25 KT
120HR VT     03/1200Z 25.0N  36.6W    20 KT...REMNANT LOW
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 282024
TCDAT4
TROPICAL DEPRESSION FOURTEEN DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL142007
500 PM EDT FRI SEP 28 2007
 
THE CLOUD PATTERN HAS NOT BECOME ANY BETTER ORGANIZED SINCE EARLIER
TODAY. THERE ARE PATCHES OF DEEP CONVECTION BUT THE OUTFLOW IS
BECOMING DISRUPTED. IN FACT...MICROWAVE DATA SHOWS THAT THE CENTER
HAS BECOME EXPOSED AND LOCATED TO THE SOUTHWEST OF THE CONVECTION.
INITIAL INTENSITY REMAINS AT 30 KNOTS. SHIPS MODEL HAS CHANGED ITS
TUNE AND SHOWS INCREASING WIND SHEAR OVER THE DEPRESSION.
CONSEQUENTLY...THE MODEL SHOWS ONLY A SLIGHT INTENSIFICATION AND SO
DOES THE OFFICIAL FORECAST. THE DEPRESSION HAS THE CHANCE...
ALTHOUGH SMALL...TO BECOME A TROPICAL STORM BEFORE THE SHEAR
INCREASES FURTHER.  THE DEPRESSION IS NOT EXPECTED TO SURVIVE
BEYOND THREE DAYS.
 
THE LOW-LEVEL CENTER IS DIFFICULT TO LOCATE AND THE BEST ESTIMATE OF
THE INITIAL MOTION IS 270/4 KNOTS. THE DEPRESSION IS EXPECTED TO
TURN TOWARD THE WEST-NORTHWEST AND NORTHWEST AROUND THE PERIPHERY
OF A NARROW HIGH PRESSURE RIDGE. THE OFFICIAL FORECAST FOLLOWS THE
GLOBAL MODELS GUIDANCE EXCEPT BEYOND 48 HOURS WHEN GLOBAL GUIDANCE
DISSIPATE THE CYCLONE.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/2100Z 14.0N  27.0W    30 KT
 12HR VT     29/0600Z 14.4N  27.7W    30 KT
 24HR VT     29/1800Z 15.0N  29.0W    35 KT
 36HR VT     30/0600Z 15.5N  30.5W    35 KT
 48HR VT     30/1800Z 16.5N  32.5W    35 KT
 72HR VT     01/1800Z 18.5N  34.5W    25 KT
 96HR VT     02/1800Z 20.0N  35.5W    20 KT...REMNANT LOW
120HR VT     03/1800Z 22.5N  36.5W    20 KT...REMNANT LOW
 
$$
FORECASTER AVILA
 

WTNT44 KNHC 290231
TCDAT4
TROPICAL DEPRESSION FOURTEEN DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL142007
1100 PM EDT FRI SEP 28 2007
 
CONVECTION ASSOCIATED WITH TROPICAL DEPRESSION FOURTEEN HAS
INCREASED DURING THE EVENING...BUT IS BEING DISPLACED EAST OF THE
CENTER BY WESTERLY VERTICAL WIND SHEAR.  AN EARLIER QUIKSCAT
OVERPASS DID NOT SHOW ANY WINDS HIGHER THAN 25 KT OUTSIDE THE
CONVECTION...WITH HIGHER SPEEDS IN THE CONVECTION LOOKING SUSPECT
DUE TO RAIN CONTAMINATION.  THE INITIAL INTENSITY REMAINS 30 KT
BASED MAINLY ON PERSISTENCE FROM THE PREVIOUS ADVISORY.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 280/4.  THE DEPRESSION IS
ON THE SOUTH SIDE OF A WEAK LOW/MID-LEVEL RIDGE...WHICH THE
LARGE-SCALE MODELS SUGGEST WILL WEAKEN AS A MID/UPPER-LEVEL TROUGH
APPROACHES FROM THE NORTH.  THIS EVOLUTION IS FORECAST TO STEER THE
DEPRESSION WEST-NORTHWESTWARD AND THEN NORTHWESTWARD.  MOST OF THE
TRACK GUIDANCE AGREES WITH THIS SCENARIO...ALTHOUGH THE ECMWF
MODELS KEEPS A STRONGER RIDGE AND IN CONSEQUENCE SHOWS A MORE
WESTERLY TRACK.  THE NEW FORECAST TRACK IS SHIFTED A LITTLE TO THE
LEFT OF THE PREVIOUS TRACK AND IS IN THE MIDDLE OF THE ENVELOPE OF
GUIDANCE.

THE LARGE-SCALE MODELS FORECAST UPPER-LEVEL WINDS TO BE MARGINALLY
FAVORABLE FOR STRENGTHENING ALONG THE FORECAST TRACK FOR PERHAPS 24
HR.  AFTER THAT...THE CYCLONE SHOULD ENCOUNTER SLIGHTLY COOLER
WATERS AND INCREASING SHEAR.  THE INTENSITY FORECAST THUS CALLS FOR
SLIGHT STRENGTHENING IN THE FIRST 12-24 HR...FOLLOWED BY WEAKENING
TO A DEPRESSION BY 36 HR AND TO A REMNANT LOW BY 96 HR.  NONE OF
THE DYNAMICAL MODELS FORECAST THE SYSTEM TO EXIST AS A CLOSED
CIRCULATION BY 120 HR...SO THE NEW INTENSITY FORECAST CALLS FOR
DISSIPATION BY THAT TIME.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/0300Z 14.2N  27.5W    30 KT
 12HR VT     29/1200Z 14.5N  28.5W    35 KT
 24HR VT     30/0000Z 15.1N  30.0W    35 KT
 36HR VT     30/1200Z 15.8N  31.8W    30 KT
 48HR VT     01/0000Z 16.8N  33.2W    30 KT
 72HR VT     02/0000Z 18.5N  35.0W    25 KT...DISSIPATING
 96HR VT     03/0000Z 20.5N  37.0W    20 KT...REMNANT LOW
120HR VT     04/0000Z...DISSIPATED
 
$$
FORECASTER BEVEN
 

