[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 080841
TCDAT4
TROPICAL STORM COLIN DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042010
500 AM AST SUN AUG 08 2010

THE LOW-LEVEL CENTER OF COLIN REMAINS DISPLACED TO THE NORTH OF THE
REMAINING DEEP CONVECTION...AS SHEAR AND DRY AIR CONTINUE TO
INHIBIT CONVECTIVE DEVELOPMENT OVER AND WEST OF THE CENTER. THE
INITIAL INTENSITY IS HELD AT 35 KT FOR THIS ADVISORY...IN AGREEMENT
WITH A DVORAK ESTIMATE OF 2.5 FROM TAFB. THE ENVIRONMENT AROUND
COLIN DOES NOT APPEAR CONDUCIVE FOR MORE THAN MODEST STRENGTHENING
OVER THE NEXT COUPLE OF DAYS...AND THE OFFICIAL FORECAST IS SIMILAR
TO THE PREVIOUS ONE...SHOWING SOME SLOW STRENGTHENING UNTIL
EXTRATROPICAL TRANSITION OCCURS IN ABOUT 3 DAYS.

THE CENTER IS DIFFICULT TO PINPOINT IN THE MULTI-CHANNEL INFRARED
IMAGERY...BUT THE INITIAL MOTION ESTIMATE IS A LITTLE FASTER
NOW...TOWARD 005 DEGREES AT 5 KT. COLIN FINALLY APPEARS TO BE
RESPONDING TO THE DEEP LAYER TROUGH MOVING OFFSHORE OF THE U.S.
EAST COAST...AND MOST OF THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON
THE GENERAL SCENARIO OF AN ACCELERATION TOWARD THE NORTH-NORTHEAST
AND NORTHEAST AHEAD OF THE TROUGH. HOWEVER...THE FORWARD SPEED OF
MOST OF THE GUIDANCE HAS TRENDED SLOWER WITH THIS CYCLE. THE
OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE...BUT TRENDS
SLOWER AFTER 12 HOURS. COLIN SHOULD UNDERGO EXTRATROPICAL
TRANSITION BY 72 HOURS BEFORE BEING ABSORBED BY A LARGER
EXTRATROPICAL CYCLONE IN ABOUT 4 DAYS. IT IS POSSIBLE THAT THE
CENTER OF COLIN COULD BECOME ELONGATED AND OPEN UP INTO A TROUGH AS
IT DECOUPLES FROM THE MID-LEVEL CENTER...AS SUGGESTED BY THE UKMET
MODEL. IF THIS OCCURS...COLIN COULD DISSIPATE EARLIER THAN
INDICATED HERE.

FORECAST POSITIONS AND MAX WINDS

INITIAL      08/0900Z 30.7N  65.6W    35 KT
 12HR VT     08/1800Z 31.7N  65.6W    35 KT
 24HR VT     09/0600Z 33.4N  65.5W    40 KT
 36HR VT     09/1800Z 36.0N  64.8W    40 KT
 48HR VT     10/0600Z 38.9N  61.9W    45 KT
 72HR VT     11/0600Z 46.0N  52.0W    45 KT...POST-TROP/EXTRATROP
 96HR VT     12/0600Z...ABSORBED BY EXTRATROPICAL LOW

$$
FORECASTER BRENNAN


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