[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 200831
TCDAT3
TROPICAL DEPRESSION THIRTEEN DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT MON SEP 20 2004

DVORAK INTENSITY ESTIMATES REMAIN AT 30 KT FROM ALL AGENCIES AND THE
INITIAL INTENSITY IS HELD AT 30 KT.  THE DEPRESSION IS MAINTAINING
A SMALL BALL OF CONVECTION NEAR THE PRESUMED CENTER BUT HAS NO
DISCERNABLE OUTFLOW PATTERN AT THIS TIME.  INDEED...THE DEPRESSION
IS CAUGHT BETWEEN HURRICANE KARL ABOUT 650 NM TO ITS WEST-NORTHWEST
AND A LARGE BUT DISORGANIZED AREA OF DISTURBED WEATHER TO ITS
SOUTHEAST.  THE GFS...NOGAPS...AND UKMET ALL MAKE THE DEPRESSION
THE WEAKEST OF THESE THREE SYSTEMS WITHIN A COUPLE OF DAYS.  WHILE
BOTH THE SHIPS AND GFDL GUIDANCE BRING THE DEPRESSION TO HURRICANE
STRENGTH...I AM RELUCTANT TO DO SO GIVEN THE COMPETING SYSTEMS IN
ITS NEAR ENVIRONMENT...AND IT IS QUITE FOSSIBLE THIS DEPRESSION
WILL BE SHORT-LIVED.

THE INITIAL MOTION ESTIMATE IS 275/10.  FOR THE NEXT DAY OR SO THE
DEPRESSION SHOULD MOVE GENERALLY WESTWARD UNDERNEATH A MID-LEVEL
RIDGE TO THE NORTHWEST OF KARL.  AFTER THAT THERE IS CONSIDERABLE
UNCERTAINTY WITH THE TRACK AS THE GUIDANCE MODELS ARE GIVING A WIDE
VARIETY OF POSSIBLE SOLUTIONS.  THE GFS LOSES THE DEPRESSION IN THE
DISTURBANCE TO THE SOUTHEAST...WHILE THE UKMET ENTRAINS IT INTO
KARL.  ON THE OTHER HAND...THE GFDL KEEPS THE DEPRESSION AND TAKES
IT WEST AND THEN WEST-SOUTHWEST AS HEIGHTS BUILD IN AFTER KARL
LIFTS OUT...WHILE THE BAM MODELS HAVE VARYING DEGREES OF A BEND TO
THE RIGHT.  CURRENTLY THE DEPRESSION IS MOVING FASTER THAN
KARL...INCREASING THE CHANCE OF IT MOVING TO THE WEST-NORTHWEST OR
NORTHWEST ON KARL'S EASTERN PERIPHERY.  THE OFFICIAL FORECAST HAS
BEEN ADJUSTED NORTH OF THE PREVIOUS FORECAST TO REFLECT THE
POSSIBILITY OF SOME INTERACTION...BUT THEN BENDS THE TRACK BACK TO
THE WEST NEAR THE END OF THE FORECAST PERIOD UNDER THE ASSUMPTION
THAT KARL WILL LEAVE THE DEPRESSION BEHIND.  GIVEN THE VERY
COMPLICATED ENVIRONMENT...THIS IS A RATHER LOW CONFIDENCE FORECAST.

FORECASTER FRANKLIN

FORECAST POSITIONS AND MAX WINDS

INITIAL      20/0900Z 13.5N  34.9W    30 KT
 12HR VT     20/1800Z 13.6N  36.4W    35 KT
 24HR VT     21/0600Z 14.1N  38.2W    40 KT
 36HR VT     21/1800Z 14.5N  39.7W    45 KT
 48HR VT     22/0600Z 15.0N  41.5W    50 KT
 72HR VT     23/0600Z 17.0N  45.0W    55 KT
 96HR VT     24/0600Z 18.0N  48.0W    55 KT
120HR VT     25/0600Z 18.5N  51.0W    55 KT


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