000
WTPZ41 KNHC 180841
TCDEP1
TROPICAL STORM COSME DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP062007
200 AM PDT WED JUL 18 2007
 
COSME CONTINUES TO MAINTAIN DEEP CONVECTION IN THE SOUTHWESTERN
QUADRANT OF ITS CIRCULATION AS IT MOVES OVER 25C WATERS.  SATELLITE
INTENSITY ESTIMATES ARE 35 AND 45 KT FROM SAB AND TAFB...
RESPECTIVELY.  UNFORTUNATELY...THE LATEST QUIKSCAT PASS MISSED THE
CYCLONE.  GIVEN THE RELATIVELY COOL WATERS...IT MAY BE APPROPRIATE
TO BE NEAR THE LOW END OF THE RANGE OF SATELLITE ESTIMATES...AND SO
THE ADVISORY INTENSITY WILL REMAIN 35 KT.
 
THE INITIAL MOTION IS 275/10.  THERE IS LITTLE CHANGE TO THE TRACK
FORECAST THINKING...WITH A LOW- TO MID-LEVEL RIDGE NORTH AND
NORTHWEST OF COSME BEING THE PRIMARY STEERING MECHANISM.  THE
LARGE-SCALE MODELS CONTINUE TO MAINTAIN THIS RIDGE FOR THE NEXT 5
DAYS...AND THIS SHOULD KEEP THE CYCLONE ON A WEST TO WEST-
NORTHWESTWARD TRACK.  THE OFFICIAL FORECAST IS VERY CLOSE TO THE
PREVIOUS ADVISORY AND THE CONSENSUS OF A TIGHTLY PACKED ENSEMBLE OF
GUIDANCE MODELS.

COSME IS MAINTAINING A RESPECTABLE AMOUNT OF CONVECTION GIVEN THE
SST'S IT IS CURRENTLY TRAVERSING.  EVEN COOLER WATERS LIE
AHEAD...HOWEVER...AND REACH A MINIMUM BEFORE THE SHEAR IS EXPECTED
TO DIMINISH IN ABOUT 48 HOURS.  AS A RESULT...THE OFFICIAL FORECAST
CALLS FOR COSME TO WEAKEN TO A DEPRESSION BY THIS TIME TOMORROW. 
AFTER THAT...SST'S ALONG THE TRACK WILL BE INCREASING...AND THERE
COULD BE SOME REGENERATION BY 72 HOURS.  NONE OF THE EXPLICIT
INTENSITY GUIDANCE...INCLUDING SHIPS...NOW SHOWS ANY DECAY AT THE
END OF THE FORECAST PERIOD.  AS A RESULT...THE CURRENT OFFICIAL
FORECAST HANGS ON TO COSME AS A TROPICAL CYCLONE THROUGHOUT...
ALTHOUGH WESTERLY SHEAR IS STILL EXPECTED TO CONTRIBUTE TO 
LATE-PERIOD WEAKENING. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      18/0900Z 15.2N 137.5W    35 KT
 12HR VT     18/1800Z 15.4N 139.2W    35 KT
 24HR VT     19/0600Z 15.7N 141.8W    30 KT
 36HR VT     19/1800Z 16.2N 144.7W    30 KT
 48HR VT     20/0600Z 16.7N 147.6W    30 KT
 72HR VT     21/0600Z 17.5N 153.5W    30 KT
 96HR VT     22/0600Z 18.5N 159.0W    25 KT
120HR VT     23/0600Z 18.5N 164.0W    25 KT
 
$$
FORECASTER FRANKLIN