114 
 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