[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 300840
TCDAT1

TROPICAL STORM KIRK DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112012
500 AM AST THU AUG 30 2012

CONVENTIONAL AND MICROWAVE SATELLITE IMAGERY HAVE SHOWN HINTS OF AN
EYE-LIKE FEATURE DURING THE PAST FEW HOURS.  DVORAK ESTIMATES FROM
TAFB AND SAB ARE AT 45 KT AND 55 KT...RESPECTIVELY...AND THE
ADVISORY INTENSITY IS SET AT THE HIGHER OF THE TWO NUMBERS GIVEN
THE MICROWAVE PRESENTATION.  KIRK IS EXPECTED TO REMAIN IN A
LOW-SHEAR ENVIRONMENT AND OVER SSTS OF AT LEAST 26C FOR THE NEXT 48
TO 72 HOURS...AND CONTINUED STRENGTHENING IS EXPECTED DURING THAT
TIME PERIOD.  VERY STRONG SOUTHWESTERLY SHEAR SHOULD BEGIN
AFFECTING THE CYCLONE FROM 72 HOURS AND BEYOND...AT WHICH POINT
KIRK SHOULD BEGIN TO WEAKEN.  KIRK IS A SMALL TROPICAL CYCLONE AND
IS THEREFORE PRONE TO QUICKER STRENGTHENING THAN A LARGE CYCLONE.
BECAUSE OF THAT...THE NHC INTENSITY FORECAST IS CLOSER TO THE
DYNAMICAL HURRICANE MODELS THAN THE STATISTICAL GUIDANCE.  THERE IS
SOME DISAGREEMENT ON WHEN KIRK WILL BECOME EXTRATROPICAL AND/OR
BECOME ABSORBED BY A FRONTAL BOUNDARY...WITH THE GFS HOLDING ON TO
A NON-FRONTAL LOW LONGER THAN THE OTHER GLOBAL MODELS.  THE
FORECAST SPLITS THE DIFFERENCE...MAKING KIRK EXTRATROPICAL IN 96
HOURS AND BECOMING ABSORBED BY A FRONT IN 120 HOURS.

THE INITIAL MOTION ESTIMATE IS 315/10.  KIRK IS ROUNDING THE WESTERN
PERIPHERY OF THE SUBTROPICAL RIDGE...AND IT SHOULD ALSO BEGIN TO
FEEL THE PRESENCE OF AN AMPLIFYING SHORTWAVE TROUGH OVER THE
WESTERN ATLANTIC DURING THE NEXT DAY OR SO.  THE TRACK GUIDANCE IS
IN GOOD AGREEMENT THAT THE CYCLONE WILL TURN NORTHWARD AND THEN
NORTHEASTWARD BEFORE IT BECOMES ABSORBED BY THE FRONT.  THE NEW
FORECAST IS SHIFTED JUST A BIT LEFT OF THE PREVIOUS ONE AND IS NEAR
THE MULTI-MODEL CONSENSUS TVCA AND TV15.


FORECAST POSITIONS AND MAX WINDS

INIT  30/0900Z 26.5N  49.0W   55 KT  65 MPH
 12H  30/1800Z 27.5N  50.1W   60 KT  70 MPH
 24H  31/0600Z 29.3N  50.8W   65 KT  75 MPH
 36H  31/1800Z 31.5N  50.8W   70 KT  80 MPH
 48H  01/0600Z 34.2N  49.3W   75 KT  85 MPH
 72H  02/0600Z 40.5N  43.0W   75 KT  85 MPH
 96H  03/0600Z 47.5N  32.5W   60 KT  70 MPH...POST-TROP/EXTRATROP
120H  04/0600Z...ABSORBED BY A FRONT

$$
FORECASTER BERG


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