000
WTPZ41 KNHC 120854
TCDEP1
TROPICAL STORM ODILE DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP162008
200 AM PDT SUN OCT 12 2008
 
BASED ON A SERIES OF SSMI AND AMSU MICROWAVE IMAGES BEFORE 06Z...THE
WEAK DISORGANIZED SURFACE CIRCULATION APPEARS TO HAVE DECOUPLED
SOUTH OF THE MID-LEVEL CENTER WHICH HAS MOVED CLOSE TO THE
MEXICO COAST NEAR MANZANILLO.  CLOUD-DRIFT DERIVED MID TO UPPER
WINDS INDICATE INCREASING SOUTHEASTERLY SHEAR ON THE ORDER OF 20 TO
30 KT OVER THE CYCLONE...WHICH ALIGNS WELL WITH THE GLOBAL MODEL
DEPICTION OF THE UPPER-WIND PATTERN.  THE INITIAL INTENSITY IS HELD
AT 35 KT SIMPLY BECAUSE THE CLOUD PATTERN...ALTHOUGH QUITE
RAGGED...HAS NOT CHANGED MUCH.  THE LARGE-SCALE MODELS ALL SUGGEST
THAT THE MODERATE SOUTHEASTERLY SHEAR WILL TRANSITION INTO A
STRONGER EASTERLY SHEAR ENVIRONMENT AROUND THE 36 HOUR PERIOD.  THE
INTENSITY FORECAST FOLLOWS THIS SCENARIO AND INDICATES WEAKENING TO
A REMNANT LOW IN 48 HOURS. 
 
INITIAL MOTION IS ESTIMATED AT 270/6...A LITTLE SLOWER AND TO THE
LEFT OF THE PREVIOUS ADVISORY.  THE FORECAST REASONING HAS CHANGED A
LITTLE DURING THE PAST 6 HOURS SINCE IT APPEARS THAT THE EXPECTED
BUILDING OF A LOW TO MID-LEVEL RIDGE BEHIND NORBERT HAS ALREADY
COMMENCED.  CONSEQUENTLY...A CONTINUED WESTWARD MOTION IS EXPECTED
DURING THE NEXT 24 HOURS OR SO WITH A GRADUAL WEST-SOUTHWESTWARD
TURN AS SUGGESTED BY THE UKMET AND ECMWF GLOBAL MODELS.  THE
OFFICIAL FORECAST IS BASED ON A BLEND OF THE GFS/NOGAPS/UKMET AND
ECMWF MODELS WHICH ALL DEPICT A SHEARED WEAKENING TROPICAL CYCLONE
DRIFTING WITHIN THE SOUTHWEST PERIPHERY OF THE AFOREMENTIONED
RIDGE.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0900Z 18.2N 104.7W    35 KT
 12HR VT     12/1800Z 18.2N 105.1W    35 KT
 24HR VT     13/0600Z 18.1N 105.7W    30 KT
 36HR VT     13/1800Z 18.0N 106.4W    25 KT
 48HR VT     14/0600Z 17.8N 107.1W    25 KT...REMNANT LOW
 72HR VT     15/0600Z 17.5N 108.0W    20 KT...REMNANT LOW
 96HR VT     16/0600Z...DISSIPATED
 
$$
FORECASTER ROBERTS/PASCH