[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 231438
TCDAT1
TROPICAL STORM DANIELLE DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062010
1100 AM AST MON AUG 23 2010

AT 1028 UTC...AN SSMIS MICROWAVE PASS INDICATED THAT DANIELLE WAS
STILL UNDER THE INFLUENCE OF EAST-NORTHEASTERLY SHEAR WITH THE
LOW-LEVEL CENTER LOCATED ON THE EASTERN EDGE OF THE DEEP
CONVECTION.  HOWEVER...THE SHEAR APPEARS TO BE SLOWLY DECREASING...
AND CURVED BANDING HAS BECOME MORE PROMINENT OVER THE PAST FEW
HOURS.  THE INITIAL INTENSITY IS RAISED TO 55 KT BASED ON DVORAK
FINAL T-NUMBERS OF 3.5 FROM TAFB AND SAB.

A FEW RECENT MICROWAVE IMAGES INDICATE THAT THE LOW-LEVEL CENTER IS
A LITTLE SOUTH OF PREVIOUS ESTIMATES...THE THE INITIAL MOTION IS
NOW 290/14.  THE LONGWAVE PATTERN OVER THE ATLANTIC IS EXPECTED TO
CHANGE LITTLE OVER THE NEXT FEW DAYS...AND A BREAK IN THE
SUBTROPICAL RIDGE NEAR 45W SHOULD ALLOW THE CYCLONE TO TURN TOWARD
THE NORTHWEST WITHIN THE NEXT 36-48 HOURS.  ONCE THIS HAPPENS...THE
RIDGE OVER THE WESTERN ATLANTIC IS EXPECTED TO BLOCK THE WESTWARD
MOVEMENT OF DANIELLE AND FORCE IT TO TURN NORTH-NORTHWESTWARD BY
DAY 5.  THE MODEL GUIDANCE IS TIGHTLY CLUSTERED THROUGH DAY 5...AND
LITTLE CHANGE FROM THE PREVIOUS FORECAST WAS NEEDED.  IT SHOULD BE
NOTED THAT THE TIGHT CLUSTERING OF THE MODEL GUIDANCE INDICATES THAT
CONFIDENCE IN THIS TRACK FORECAST IS HIGHER THAN NORMAL.

THE INTENSITY GUIDANCE CONTINUES TO SHOW STEADY STRENGTHENING
OVER THE NEXT 36 TO 48 HOURS WITH THE HELP OF LOW VERTICAL SHEAR AND
WARM OCEAN WATERS.  AS COMPARED TO YESTERDAY...HOWEVER...THE SHIPS
AND LGEM STATISTICAL MODELS NOW SHOW MORE INTENSIFICATION THAN THE
GFDL AND HWRF DYNAMICAL MODELS.  THE OFFICIAL FORECAST IS CLOSE TO
THE SHIPS AND LGEM MODELS FOR THE FIRST 72 HOURS BUT THEN VERY
CLOSE TO THE CONSENSUS AND PREVIOUS FORECAST THEREAFTER.  THE RAPID
INTENSIFICATION INDEX IS CURRENTLY NEAR 40 PERCENT...SO THERE IS
SOME CHANCE THAT DANIELLE COULD STRENGTHEN A LITTLE FASTER DURING
THE NEXT 24 HOURS THAN INDICATED IN THE FORECAST.  BY DAYS 3
THROUGH 5...VERTICAL SHEAR COULD INCREASE AS DANIELLE APPROACHES A
LONGWAVE TROUGH OVER THE WESTERN ATLANTIC... SO FOR NOW THE
INTENSITY IS HELD NEAR THE LOWER END OF CATEGORY 2 STRENGTH.  THERE
IS NOW A 1 IN 4 CHANCE...HIGHER THAN YESTERDAY...THAT DANIELLE
COULD BECOME A MAJOR HURRICANE DURING THE NEXT 5 DAYS BASED ON
HISTORICAL NHC INTENSITY ERRORS.


FORECAST POSITIONS AND MAX WINDS

INITIAL      23/1500Z 15.1N  39.4W    55 KT
 12HR VT     24/0000Z 16.0N  41.5W    65 KT
 24HR VT     24/1200Z 17.3N  44.5W    75 KT
 36HR VT     25/0000Z 18.9N  47.2W    80 KT
 48HR VT     25/1200Z 20.8N  49.5W    85 KT
 72HR VT     26/1200Z 24.5N  53.5W    90 KT
 96HR VT     27/1200Z 27.0N  55.5W    90 KT
120HR VT     28/1200Z 29.5N  57.0W    90 KT

$$
FORECASTER BERG



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