Tropical Depression ROSA

ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL DEPRESSION ROSA DISCUSSION NUMBER  21
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172012
200 AM PDT SUN NOV 04 2012
 
ROSA STILL HAS A WELL-DEFINED LOW- TO MID-LEVEL CIRCULATION BASED ON
CONVENTIONAL AND PASSIVE MICROWAVE SATELLITE IMAGERY. A 04/0452 UTC
ASCAT OVERPASS INDICATED SURFACE WINDS OF ABOUT 25 KT IN THE
EASTERN SEMICIRCLE...AND THAT THE RADIUS OF MAXIMUM WINDS HAVE
EXPANDED OUTWARD TO ABOUT 60 NMI. HOWEVER...SINCE THE ASCAT PASS...
A CURVED BAND OF MODERATE CONVECTION HAS DEVELOPED IN THE EASTERN
SEMICIRCLE...AND A SMALL BURST OF DEEP CONVECTION HAS ALSO
DEVELOPED OVER AND JUST SOUTH OF THE LOW-LEVEL CENTER. GIVEN THE
RECENT INCREASE IN CONVECTION AND THE FACT THAT ROSA IS HEADING
INTO THE NOCTURNAL CONVECTIVE MAXIMUM PERIOD...THE SYSTEM IS BEING
MAINTAINED AS A 25-KT TROPICAL CYCLONE FOR THIS ADVISORY.

THE INITIAL MOTION ESTIMATE IS SLOWLY WESTWARD...OR 270/03 KT. ROSA
MADE A SLIGHT SOUTHWESTWARD JOG SINCE THE PREVIOUS ADVISORY...BUT
THIS MOTION IS EXPECTED TO BE TEMPORARY. A WESTWARD OR EVEN A
WEST-NORTHWESTWARD MOTION IS EXPECTED TO RESUME AND CONTINUE FOR
THE NEXT 48 HOURS OR SO AS THE CYCLONE AND ITS REMNANTS ARE STEERED
BY WEAK LOW-LEVEL EASTERLY TRADEWIND FLOW. THE NHC FORECAST TRACK
IS A LITTLE SOUTH OF THE PREVIOUS ADVISORY TRACK TRACK...AND
CLOSELY FOLLOWS THE ECMWF MODEL AND THE DYNAMICAL CONSENSUS MODELS.

WATER VAPOR IMAGERY INDICATES ROSA IS MOVING WESTWARD INTO STRONG
UPPER-LEVEL WEST-SOUTHWESTERLY WINDS AND VERTICAL SHEAR VALUES IN
EXCESS OF 40 KT...AND ALSO INTO AN INCREASINGLY DRIER AIR MASS.
OTHER THAN BRIEF BURSTS OF MODERATE CONVECTION...THESE UNFAVORABLE
ENVIRONMENTAL CONDITIONS SHOULD RESULT IN ROSA DEGENERATING INTO A
REMNANT LOW PRESSURE SYSTEM DURING THE NEXT 12 HOURS OR SO. THE
OFFICIAL INTENSITY FORECAST FOLLOWS THE TREND OF THE PREVIOUS
ADVISORY AND THE LATEST INTENSITY GUIDANCE...AND SHOWS A GRADUAL
WEAKENING TREND OVER THE NEXT COUPLE OF DAYS WITH DISSIPATION
EXPECTED BY 72 HOURS...IF NOT SOONER.

FORECAST POSITIONS AND MAX WINDS
 
INIT  04/0900Z 12.5N 121.5W   25 KT  30 MPH
 12H  04/1800Z 12.6N 121.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  05/0600Z 12.8N 122.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  05/1800Z 13.0N 122.4W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  06/0600Z 13.0N 123.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  07/0600Z...DISSIPATED
 
$$
FORECASTER STEWART
 
NNNN