000
WTPZ43 KNHC 201237
TCDEP3
TROPICAL DEPRESSION EIGHT-E SPECIAL DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP082010
530 AM PDT FRI AUG 20 2010
 
SATELLITE IMAGERY AND AN ASCAT PASS FROM AROUND 0445 UTC SUGGEST
THAT THE AREA OF LOW PRESSURE LOCATED A COUPLE HUNDRED MILES WEST
OF MANZANILLO HAS BECOME A TROPICAL DEPRESSION.  THE INITIAL
INTENSITY IS SET TO 30 KT BASED ON THE ASCAT PASS.  THE
MULTI-CHANNEL INFRARED IMAGERY SUGGESTS THAT THE LOW-LEVEL CENTER
IS LOCATED NEAR THE NORTHEAST EDGE OF THE DEEP CONVECTION...
CONSISTENT WITH THE SHEAR VECTOR ANALYZED BY SHIPS AND UW-CIMSS.  

THE DEPRESSION HAS A VERY NARROW WINDOW OF TIME IN WHICH TO
STRENGTHEN...AS IT WILL BE MOVING INTO SUB 27-C WATERS IN 36 TO 48
HOURS.  ADDITIONALLY...THE SHIPS MODEL FORECASTS SHEAR OF 20 TO 30
KNOTS TO CONTINUE OVER THE CYCLONE UNTIL IT REACHES THE COOLER
WATER.  AS A RESULT...THE OFFICIAL INTENSITY FORECAST SHOWS ONLY A
LITTLE STRENGTHENING TODAY...FOLLOWED BY SLOW WEAKENING TO A
REMNANT LOW IN ABOUT 48 HOURS...WITH DISSIPATION EXPECTED IN ABOUT
3 DAYS. 

THE CURRENT MOTION ESTIMATE IS A RATHER UNCERTAIN 320/6.  THE
DEPRESSION IS SITUATED TO THE SOUTH OF A DEEP-LAYER RIDGE EXTENDING
ACROSS THE EASTERN PACIFIC AND NORTHERN MEXICO.  ALL OF THE TRACK
GUIDANCE SUGGESTS THE DEPRESSION WILL TURN TOWARD THE
WEST-NORTHWEST IN THE NEXT DAY OR SO...AND THIS IS REFLECTED IN THE
OFFICIAL FORECAST.  BEYOND THAT TIME A SLOW WEST TO WEST-NORTHWEST
MOTION IS EXPECTED UNTIL THE CYCLONE DISSIPATES.  THE OFFICIAL
FORECAST LIES TO THE RIGHT OF ALL OF THE GUIDANCE...ESPECIALLY IN
THE FIRST 12 TO 24 HOURS DUE TO THE INITIAL POSITION AND MOTION OF
THE SYSTEM. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/1230Z 18.7N 107.8W    30 KT
 12HR VT     20/1800Z 19.3N 108.3W    35 KT
 24HR VT     21/0600Z 20.0N 109.7W    30 KT
 36HR VT     21/1800Z 20.4N 111.0W    30 KT
 48HR VT     22/0600Z 20.6N 112.1W    25 KT...POST-TROP/REMNT LOW
 72HR VT     23/0600Z...DISSIPATED
 
$$
FORECASTER BRENNAN