000
WTNT41 KNHC 242040
TCDAT1
TROPICAL STORM DANIELLE DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062010
500 PM AST TUE AUG 24 2010
 
WITH JUST A LITTLE BIT OF UNEXPECTED WESTERLY SHEAR...DANIELLE HAS
UNRAVELED DURING THE DAY.  THE LOW-LEVEL CENTER HAS OCCASIONALLY
BEEN EXPOSED TO THE WEST OF A DISORGANIZED CLUSTER OF DEEP
CONVECTION...AND THE DVORAK ESTIMATES HAVE DECREASED ACCORDINGLY.
FINAL-T AND CI ESTIMATES FROM THE UW-CIMSS ADT ARE NOW NEAR
T3.5/4.5 AND SUPPORT DOWNGRADING DANIELLE TO A 60-KT TROPICAL
STORM.  WITHOUT SUFFICIENT OBSERVATIONAL DATA IN THE CYCLONE
ENVIRONMENT...OPERATIONALLY WE CAN NOT SPECULATE WITH CERTAINTY WHY
DANIELLE WEAKENED TODAY.
 
ENVIRONMENTAL CONDITIONS SUPPORT DANIELLE RE-INTENSIFYING INTO A
HURRICANE SOON...AND THAT IS REFLECTED IN THE OFFICIAL FORECAST.
THE INTENSITY GUIDANCE...EXCEPT FOR THE GFDL WHICH SHOWS DANIELLE
BECOMING AN INTENSE HURRICANE IN ABOUT 4 DAYS...INDICATES GRADUAL
STRENGTHENING DURING THE FORECAST PERIOD.  THE NEW OFFICIAL
FORECAST IS HIGHER THAN THE STATISTICAL MODELS...WHICH ARE STRONGLY
AFFECTED BY PERSISTENCE...BUT IT REMAINS MUCH LOWER THAN THE GFDL
AT THIS TIME.
 
DANIELLE IS STILL MOVING QUICKLY WITH AN INITIAL MOTION OF 295/16.
THE TRACK GUIDANCE INDICATES THAT THE CYCLONE SHOULD BEGIN TO SLOW
DOWN SOON AND TURN TOWARD THE NORTHWEST WITHIN THE NEXT 24 HOURS AS
IT MOVES INTO A WEAKNESS IN THE SUBTROPICAL RIDGE.  THE MODELS HAVE
SHIFTED SIGNIFICANTLY TO THE WEST...HOWEVER...AND THE DAY 5
OFFICIAL FORECAST POSITION ENDS UP BEING 2 DEGREES FARTHER WEST
THAN IN THE PREVIOUS FORECAST.  THIS NEW FORECAST IS STILL TO THE
RIGHT OF THE GFDL AND HWRF MODELS...AND IT LIES CLOSE TO THE MODEL
CONSENSUS OUT OF RESPECT FOR THE SHARPER-TURNING ECMWF.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/2100Z 17.5N  48.2W    60 KT
 12HR VT     25/0600Z 18.5N  49.9W    70 KT
 24HR VT     25/1800Z 20.2N  51.9W    75 KT
 36HR VT     26/0600Z 22.0N  53.8W    80 KT
 48HR VT     26/1800Z 23.7N  55.3W    85 KT
 72HR VT     27/1800Z 26.5N  58.5W    90 KT
 96HR VT     28/1800Z 29.5N  61.0W    95 KT
120HR VT     29/1800Z 33.0N  61.5W    95 KT
 
$$
FORECASTER BERG