[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 030838
TCDAT4

TROPICAL DEPRESSION DORIAN DISCUSSION NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042013
500 AM AST SAT AUG 03 2013

RADAR AND SATELLITE IMAGERY THIS MORNING INDICATE THAT THE
CONVECTION ASSOCIATED WITH THE LOW PRESSURE SYSTEM...THE REMNANTS
OF DORIAN...LOCATED EAST OF CAPE CANAVERAL FLORIDA HAS INCREASED
AND BECOME BETTER ORGANIZED AROUND THE CIRCULATION CENTER. ASCAT-B
AND ASCAT-A OVERPASSES AT 0200 UTC AND 0244 UTC...RESPECTIVELY...
DEPICTED A LARGE AREA OF 30-KT WINDS IN THE SOUTHEASTERN QUADRANT
ALONG WITH A COUPLE OF ISOLATED 35- TO 36-KT VECTORS. IN
ADDITION...DOPPLER VELOCITY DATA FROM THE MELBOURNE FLORIDA WSR-88D
RADAR HAS OCCASIONALLY BEEN INDICATING PATCHES OF 35- TO 40-KT
WINDS WITH ISOLATED VALUES TO 45 KT AT 5000-5500 FT ON THE SOUTH
SIDE OF THE CIRCULATION. BASED ON ALL OF THE AFOREMENTIONED DATA...
ADVISORIES ARE BEING RE-INITIATED ON TROPICAL DEPRESSION DORIAN.

AN INITIAL INTENSITY OF 30 KT IS BEING ASSIGNED TO DORIAN BASED ON
THE LARGER-SCALE WIND FIELD NOTED IN ASCAT DATA. ALTHOUGH DORIAN
COULD BE NEAR TROPICAL STORM STRENGTH...I HAVE OPTED TO ACCOUNT FOR
ANY HIGHER WINDS BY INCREASING THE GUST FACTOR FROM THE STANDARD 40
KT UP TO 45 KT. ENVIRONMENTAL FACTORS ARE GENERALLY FAVORABLE FOR
STRENGTHENING...EXCEPT FOR THE MODERATE NORTHERLY VERTICAL WIND
SHEAR OF ABOUT 20 KT...WHICH IS FORECAST TO INCREASE TO MORE THAN
30 KT BY 18-24 HOURS. THEREFORE...THE INTENSITY FORECAST CALLS FOR
LITTLE CHANGE IN STRENGTH FOR THE NEXT 24 HOURS OR SO...WITH
GRADUAL WEAKENING THEREAFTER DUE TO THE EXPECTED STRONGER WIND
SHEAR. AN ALTERNATIVE SCENARIO IS THAT DORIAN COULD SHEAR APART AND
WEAKEN SOONER THAN FORECAST. THE INTENSITY FORECAST IS SIMILAR TO
BUT SLIGHTLY BELOW THE INTENSITY CONSENSUS MODEL ICON.

THE INITIAL MOTION ESTIMATE IS 010/05 KT. THE GLOBAL AND REGIONAL
MODELS ARE IN GOOD AGREEMENT ON THE LOW-LEVEL CENTER MOVING
NORTHWARD FOR THE NEXT 12-24 HOURS AROUND THE WESTERN PERIPHERY OF
THE STRONG BERMUDA-AZORES HIGH...AND THEN TURNING NORTHEASTWARD
AHEAD OF AN APPROACHING FRONTAL ZONE ON SUNDAY AND MONDAY. BY 72
HOURS...DORIAN IS EXPECTED TO BE ABSORBED BY THE FRONTAL SYSTEM
WHEN IT IS LOCATED WELL TO THE WEST OR NORTHWEST OF BERMUDA. THE
OFFICIAL FORECAST TRACK IS DOWN THE MIDDLE OF THE NHC GUIDANCE
ENVELOPE AND CLOSELY FOLLOWS THE CONSENSUS TRACK MODEL TVCA.

IT SHOULD BE NOTED THAT IF DORIAN DOES BECOME A MINIMAL TROPICAL
STORM DURING THE NEXT 12 HOURS OR SO...THE STRONGEST WINDS ARE
EXPECTED TO REMAIN IN THE SOUTHEASTERN QUADRANT OF THE CYCLONE...
WHICH WOULD PRECLUDE THE NEED FOR ANY TROPICAL STORM WARNINGS OR
WATCHES FOR ANY LAND AREAS.

FORECAST POSITIONS AND MAX WINDS

INIT  03/0900Z 28.7N  79.2W   30 KT  35 MPH
 12H  03/1800Z 29.9N  78.4W   30 KT  35 MPH
 24H  04/0600Z 31.4N  76.0W   30 KT  35 MPH
 36H  04/1800Z 33.0N  72.2W   25 KT  30 MPH
 48H  05/0600Z 35.2N  67.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  06/0600Z...ABSORBED BY A FRONTAL ZONE

$$
FORECASTER STEWART



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