000
WTPZ42 KNHC 030839
TCDEP2
 
TROPICAL STORM ROSA DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172012
200 AM PDT SAT NOV 03 2012
 
CONVENTIONAL SATELLITE IMAGERY SHOWS ROSA MAINTAINING A SHEARED
SCENE TYPE THIS MORNING...WITH A SMALL AREA OF -80C OVERSHOOTING
COLD CLOUD TOPS NEAR THE PARTLY EXPOSED CENTER OF CIRCULATION.
ALTHOUGH THE DVORAK SATELLITE INTENSITY ESTIMATES ARE 2.5/35 KT
FROM BOTH TAFB AND SAB...THE INITIAL INTENSITY WILL REMAIN THE SAME
AS THE PREVIOUS ADVISORY...40 KT...DUE TO LITTLE OR NO CHANGE IN
THE CLOUD PATTERN FROM 6 HOURS AGO. UW-CIMSS SHEAR PRODUCT AND
WATER VAPOR IMAGERY SHOW ROSA MOVING IN AN UNFORGIVING ENVIRONMENT
CONSISTING OF 30-40 KT OF SOUTHWESTERLY SHEAR AND AN INTRUDING
DRY/STABLE MARINE-LAYER AIR MASS. THESE TWO INHIBITING
CONTRIBUTIONS SHOULD QUICKLY WEAKEN ROSA INTO A DEPRESSION WITHIN
THE NEXT 12 HOURS...AND ULTIMATELY TO A POST-TROPICAL REMNANT LOW
IN 24 HOURS. THE OFFICIAL INTENSITY FORECAST ALSO REFLECTS
DISSIPATION BY DAY 4 WHICH IS CONSISTENT WITH A CONSENSUS OF THE
GLOBAL MODELS.
 
THE INITIAL MOTION ESTIMATE IS A PERSISTENT 260/4...OR TOWARD THE
WEST. A LOW- TO MID-TROPOSPHERIC NARROW RIDGE TO THE NORTH IS
STEERING THE CYCLONE ON ITS CURRENT HEADING. A MAJORITY OF
THE DYNAMICAL MODELS CONTINUE TO INDICATE THAT ROSA WILL TURN
TOWARD THE NORTHWEST AROUND THE 24 HOUR PERIOD IN RESPONSE TO AN
AMPLIFYING DEEP-LAYER TROUGH TO THE NORTHWEST OF THE TROPICAL
STORM.  THE GUIDANCE SPREAD...UNFORTUNATELY...REMAINS QUITE LARGE.
THE UKMET IS SHOWING A FLATTER TRACK...A GENERAL WEST TO
WEST-NORTHWEST DIRECTION WITH TIME...WHILE THE GFS IS TO THE FAR
RIGHT OF THE MODEL CLUSTER AND INDICATES A SHARP TURN TOWARD THE
NORTH IN 12 HOURS. THE NHC TRACK FORECAST RESEMBLES THE PREVIOUS
ADVISORY AND IS BASED ON THE MULTI-MODEL CONSENSUS WHICH IS
ESSENTIALLY BETWEEN THE TWO AFOREMENTIONED OUTLIERS.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/0900Z 12.6N 119.7W   40 KT  45 MPH
 12H  03/1800Z 12.7N 120.1W   30 KT  35 MPH
 24H  04/0600Z 12.8N 120.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  04/1800Z 13.1N 120.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  05/0600Z 13.5N 121.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  06/0600Z 14.3N 122.3W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  07/0600Z...DISSIPATED
 
$$
FORECASTER ROBERTS