000
WTPZ44 KNHC 292042
TCDEP4
 
TROPICAL STORM HILARY DISCUSSION NUMBER  35
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092011
200 PM PDT THU SEP 29 2011
 
A NOAA HURRICANE HUNTER PLANE CONDUCTING A RESEARCH MISSION IN
HILARY MEASURED A PEAK SURFACE WIND OF 44 KT FROM THE SFMR AND A
7000-FT FLIGHT-LEVEL WIND OF 55 KT WITHIN THE NORTHEASTERN
QUADRANT.  BASED ON THIS DATA...THE INITIAL INTENSITY RESET TO 45
KT.  THE MINIMUM PRESSURE IS 1000 MB BASED ON DATA FROM A DROPSONDE
RELEASED IN THE SECOND PASS THROUGH THE CENTER.  HILARY IS ONLY
PRODUCING ONE SMALL CLUSTER OF DEEP CONVECTION TO THE NORTHEAST OF
THE CENTER...AND THE CYCLONE IS EXPECTED TO GRADUALLY SPIN DOWN AS
IT MOVES OVER INCREASINGLY COOLER WATERS.  EVEN IF HILARY STOPS
PRODUCING DEEP CONVECTION SOON...IT COULD TAKE A LITTLE LONGER FOR
THE WINDS TO FALL BELOW TROPICAL STORM FORCE.  THIS IS NOTED IN THE
OFFICIAL FORECAST BY THE POST-TROPICAL DESIGNATION AT 24 HOURS. 
THE GLOBAL MODELS INDICATE THAT THE REMNANT LOW SHOULD DEGENERATE
INTO A TROUGH BY 96 HOURS.

THE INITIAL MOTION IS 335 DEGREES AT 8 KT.  HILARY IS EXPECTED TO
MAINTAIN A NORTH-NORTHWESTWARD MOTION UNTIL A LOW-LEVEL RIDGE
BUILDS ALONG 32N BY 24 HOURS.  THE RIDGE SHOULD FORCE THE REMNANT
LOW WESTWARD AFTER 24 HOURS UNTIL DISSIPATION.  SOME OF THE GLOBAL
MODELS EVEN SUGGEST THAT HILARY COULD ACQUIRE A WEST-SOUTHWESTWARD
MOTION BEFORE IT DISSIPATES.

MANY THANKS TO THE NOAA HURRICANE RESEARCH DIVISION AND AIRCRAFT
OPERATIONS CENTER FOR THE DATA RECEIVED DURING THE RESEARCH
MISSION.  HOPEFULLY THIS DATA WILL GO A LONG WAY IN HELPING US
PROVIDE BETTER INTENSITY FORECASTS FOR TROPICAL CYCLONES WEAKENING
OVER COLDER WATERS.

FORECAST POSITIONS AND MAX WINDS
 
INIT  29/2100Z 21.6N 120.7W   45 KT  50 MPH
 12H  30/0600Z 22.5N 121.1W   35 KT  40 MPH...POST-TROPICAL
 24H  30/1800Z 23.4N 121.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  01/0600Z 23.8N 122.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  01/1800Z 23.8N 122.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  02/1800Z 23.5N 124.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  03/1800Z...DISSIPATED
 
$$
FORECASTER BERG