15Z Tropical Update

TROPICAL STORM COLIN FORECAST #3
TROPICAL FORECAST CENTER
10:45 AM EDT TUESDAY AUGUST 3, 2010

AT 11:00 AM EDT/1500Z...THE CENTER OF TROPICAL STORM COLIN WAS LOCATED NEAR 14.2 N 49.5 W OR 840 MILES EAST-SOUTHEAST OF THE LEEWARD ISLANDS. MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH AND SOME GRADUAL STRENGTHENING IS EXPECTED DURING THE NEXT 24 HOURS. MOTION OF COLIN IS WEST AT 24 MPH AND A GRADUAL TURN BACK TO THE WEST-NORTHWEST WITH A DECREASE IN FORWARD SPEED IS EXPECTED. ON THE FORECAST TRACK...COLIN IS EXPECTED TO MISS THE NORTHERN LEEWARD ISLANDS BUT ANY FURTHER TURN TO THE WEST COULD PROMPT TROPICAL STORM WATCHES. MINIMUM ESTIMATE CENTRAL PRESSURE IS 1006 MB/29.71 IN.

COLIN WAS UPGRADED TO A TROPICAL STORM DURING THE OVERNIGHT HOURS AND SINCE...THE APPEARANCE OF THIS STORM IS FAIRLY RAGGED TO SAY THE LEAST AND APPEARS THAT SOME WESTERLY SHEAR HAVE IMPACTED COLIN SOME. DVORAK ESTIMATES SHOW THAT COLIN SHOULD BE STILL A DEPRESSION...WHILE BOTH THE ADT AND MIMIC-IR SHOW THAT COLIN IS A 45 MPH TROPICAL STORM. BASED ON THE RAGGED APPEARANCE AND THE LACK OF DEEP THUNDERSTORMS...THE INITIAL INTENSITY WILL BE KEPT AT 35 KTS. COLIN IS STRUGGLING TO KEEP ANY DEEP THUNDERSTORMS FOR A LONG PERIOD OF TIME DUE TO HIS RAPID FORWARD MOTION AND WHAT COULD BE THE BEGINNING EFFECTS OF THE WESTERLY SHEAR. THOUGH I DO SHOW COLIN EVENTUALLY FIGHTING THIS AND GRADUALLY STRENGTHENING THROUGH THE FORECAST PERIOD...IT DO HAVE TO BE MENTIONED THAT THERE IS A POSSIBILITY THAT COLIN DUE TO HIS RAPID MOTION BECOMING AN OPEN WAVE IN A FEW DAYS.

INITIAL MOTION IS AGAIN A SWIFT 280/21 KTS. COLIN HAVE BEEN MOVING WEST DURING THE PAST FEW HOURS AND THIS IS LIKELY A TEMPORARY MOTION AS A WEST-NORTHWEST MOTION IS EXPECTED TO RESUME ALONG THE SOUTHERN FLANK OF THE BERMUDA HIGH. WITH COLIN BEING A WEAK SYSTEM...HE WILL LIKELY FIND THE WEAKNESS IN THE HIGH AND BEGIN TO SLOW DOWN IN ABOUT 36 HOURS. MODEL GUIDANCE FOLLOW THIS CLOSELY THROUGH 36 HOURS AND THEN GRADUAL DIVERGE ON WHERE COLIN COULD GO. GROUP OF MODELS CONTINUE COLIN TO THE WEST-NORTHWEST AND GET CAUGHT UP IN A TROUGH AND RECURVE OUT TO SEA...POSSIBLY AFFECTING BERMUDA...WHILE A FEW OTHERS CONTINUE COLIN ON A WEST-NORTHWEST FOLLOWED BY A NORTHWEST MOTION CLOSER TO THE SOUTHEAST U.S. MY FORECAST TRACK IS BASICALLY AN UPDATE FROM THE PREVIOUS FORECAST WITH A SLIGHT LEFTWARD ADJUSTMENT AND NHC HAS APPARENTLY CAUGHT UP TO THIS SUGGESTION DUE TO THE SIMILAR FORECAST TRACK THAT THEY HAVE.

FORECAST POSITION AND INTENSITY:

03/15Z 14.2 N 49.5 W 35 KTS
04/03Z 15.3 N 52.1 W 40 KTS
04/15Z 16.7 N 55.8 W 50 KTS
05/03Z 18.3 N 59.2 W 55 KTS
05/15Z 20.0 N 62.1 W 60 KTS
06/15Z 23.0 N 66.5 W 60 KTS
07/15Z 26.5 N 68.5 W 60 KTS
08/15Z 28.0 N 70.5 W 60 KTS

JACKSON