000
WTPZ45 KNHC 080245
TCDEP5
 
TROPICAL STORM OLIVIA DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP152012
800 PM PDT SUN OCT 07 2012
 
IT HAS BEEN DIFFICULT TO ASSESS THE STRUCTURE AND PRECISE LOCATION
OF OLIVIA IN GEOSTATIONARY SATELLITE IMAGES THIS EVENING.  THE MOST
RECENT MICROWAVE IMAGERY SUGGESTS THAT THERE IS A SOUTHWEST-TO-
NORTHEAST TILT BETWEEN THE LOW- AND MID-LEVEL CENTERS DUE TO
MODERATE SOUTHWESTERLY SHEAR.  HOWEVER...THE RESOLUTION OF THE DATA
DO NOT ALLOW A CLEAR PEEK OF THE INNER-CORE STRUCTURE OF THIS SMALL
TROPICAL CYCLONE.  DVORAK DATA T-NUMBERS ARE VIRTUALLY UNCHANGED
FROM THIS AFTERNOON...AND A BLEND OF THE VARIOUS SATELLITE-BASED
INTENSITY ESTIMATES STILL SUPPORT AN INITIAL WIND SPEED OF 50 KT. 

THE SOUTHWESTERLY SHEAR THAT IS CURRENTLY AFFECTING OLIVIA IS NOT
EXPECTED TO INCREASE IN THE SHORT TERM...SO THERE IS STILL SOME
POTENTIAL FOR THE CYCLONE TO STRENGTHEN SLIGHTLY TONIGHT OR EARLY
MONDAY AS IT REMAINS OVER WARM WATER.  IN A DAY OR SO...THE SHEAR
IS FORECAST TO INCREASE...AND THE GLOBAL MODELS SHOW THAT THE LOW-
AND MID-LEVEL CENTERS ARE LIKELY TO DECOUPLE WITHIN 48 HOURS.  THE
NHC INTENSITY FORECAST SHOWS OLIVIA REACHING PEAK INTENSITY VERY
SOON AND CALLS FOR GRADUAL WEAKENING THEREAFTER.  THE NHC FORECAST
PREDICTS THAT THE CYCLONE WILL BECOME A REMNANT LOW SOONER THAN IN
THE PREVIOUS ADVISORY.
 
OLIVIA IS MOVING NORTHWARD OR 355 DEGREES AT 6 KT. THE TROPICAL
STORM SHOULD CONTINUE NORTHWARD AROUND THE WESTERN SIDE OF A
MID-LEVEL RIDGE OVER THE EASTERN PACIFIC. THE RIDGE IS FORECAST TO
WEAKEN AS A LARGE UPPER-LEVEL LOW DROPS SOUTHEASTWARD ALONG THE
CENTRAL AND SOUTHERN CALIFORNIA COASTS DURING THE NEXT FEW DAYS...
AND THIS SHOULD CAUSE THE FORWARD SPEED OF OLIVIA TO DECREASE.
AFTER THE TROPICAL CYCLONE WEAKENS AND BECOMES A SHALLOW SYSTEM...
IT IS EXPECTED TO TURN WESTWARD AND THEN SOUTHWESTWARD IN THE
LOW-LEVEL NORTHEASTERLY FLOW. THE NHC TRACK FORECAST IS NEAR THE
MIDDLE OF THE GUIDANCE ENVELOPE AND CLOSE TO THE PREVIOUS ADVISORY.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/0300Z 16.2N 120.9W   50 KT  60 MPH
 12H  08/1200Z 16.8N 120.9W   55 KT  65 MPH
 24H  09/0000Z 17.3N 121.0W   50 KT  60 MPH
 36H  09/1200Z 17.4N 121.5W   45 KT  50 MPH
 48H  10/0000Z 17.2N 122.2W   35 KT  40 MPH
 72H  11/0000Z 16.9N 123.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  12/0000Z 16.0N 125.7W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  13/0000Z...DISSIPATED
 
$$
FORECASTER BROWN