000
WTPZ43 KNHC 030836
TCDEP3
TROPICAL DEPRESSION OLAF DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP182009
200 AM PDT SAT OCT 03 2009
 
A SERIES OF MICROWAVE PASSES INDICATE THAT THE LOW-LEVEL CENTER OF
OLAF IS LOCATED WELL TO THE WEST OF THE MID-LEVEL CIRCULATION THAT
IS APPARENT IN SHORTWAVE INFRARED IMAGES. THIS DECOUPLED STRUCTURE
IS DUE TO ABOUT 25 KT OF SOUTHWESTERLY VERTICAL WIND SHEAR...
ACCORDING TO ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN. A
0532 UTC HIGH RESOLUTION ASCAT PASS SHOWED MAXIMUM WINDS IN THE
25-30 KT RANGE. BASED ON THIS PASS AND SATELLITE INTENSITY
ESTIMATES...OLAF IS BEING DOWNGRADED TO A TROPICAL DEPRESSION WITH
THE INITIAL INTENSITY SET AT 30 KT. DESPITE SLIGHTLY WARMER SEA
SURFACE TEMPERATURES ALONG THE FORECAST TRACK...OLAF IS EXPECTED TO
WEAKEN DUE TO EVEN STRONGER SHEAR FORECAST BY THE SHIPS MODEL. 
OLAF IS FORECAST TO BECOME A REMNANT LOW BY 36 HOURS...IN AGREEMENT
WITH MUCH OF THE MODEL GUIDANCE.

BASED ON MICROWAVE DATA...THE INITIAL MOTION HAS SLOWED AND IS
SLIGHTLY LEFT OF THE PREVIOUS ESTIMATE AT 010/3. OLAF WILL SHORTLY
TURN NORTHEASTWARD...IF IT HAS NOT ALREADY...AND ACCELERATE AS IT
MOVES INTO DEEP-LAYER SOUTHWESTERLY FLOW TAKING OLAF OR ITS
REMNANTS ACROSS THE CENTRAL BAJA PENINSULA TONIGHT. THIS TRACK
FORECAST IS A LITTLE SLOWER THAN THE PREVIOUS ONE TO ACCOUNT FOR
THE INITIAL MOTION.

RAINFALL ASSOCIATED WITH OLAF WILL CONTINUE TO SPREAD INTO CENTRAL
PORTIONS OF THE BAJA PENINSULA AND NORTHWESTERN MEXICO TODAY AND
TONIGHT.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      03/0900Z 24.1N 117.2W    30 KT
 12HR VT     03/1800Z 25.3N 116.1W    30 KT
 24HR VT     04/0600Z 26.5N 114.4W    25 KT
 36HR VT     04/1800Z 27.5N 111.6W    20 KT...REMNANT LOW
 48HR VT     05/0600Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI/BEVEN