000
WTPZ45 KNHC 040321
TCDEP5
TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152008
800 PM PDT FRI OCT 03 2008
 
THE BROAD LOW PRESSURE SYSTEM THAT HAS BEEN FESTERING SOUTH OF
SOUTHERN MEXICO FOR THE PAST 4 DAYS OR SO HAS FINALLY DEVELOPED
ENOUGH CONVECTIVE BANDING TO BE CLASSIFIED AS A TROPICAL
DEPRESSION. SATELLITE INTENSITY ESTIMATES ARE T2.0/30 KT AND
T1.5/25 KT FROM TAFB AND SAB...RESPECTIVELY. HOWEVER...A QUIKSCAT
OVERPASS EARLIER IN THE DAY INDICATED SOME 25-30 KT WIND VECTORS
OUTSIDE RAIN AREAS...AND CONVECTION HAS BECOME BETTER ORGANIZED AND
MORE CENTRALIZED SINCE THAT OVERPASS...ESPECIALLY SINCE 01Z.
THEREFORE...THE INITIAL INTENSITY IS SET AT 30 KT.

THE INITIAL MOTION IS A SLOW DRIFT TOWARD THE NORTH AT 02 KT. ALL OF
THE NHC MODEL GUIDANCE...EXCEPT FOR THE HWRF MODEL...TAKE THE
DEPRESSION SLOWLY TOWARD THE WEST-NORTHWEST OR NORTHWEST DURING THE
FORECAST PERIOD. HWRF TAKES THE CYCLONE IMMEDIATELY DUE NORTH AND
MOVES INTO THE SOUTH-CENTRAL COAST OF MEXICO IN 36-48 HOURS. THE
HWRF SCENARIO IS BEING DISCOUNTED AT THIS TIME DUE TO A LARGE-SCALE
SUBTROPICAL RIDGE FORECAST TO BUILD WESTWARD ACROSS EASTERN AND
CENTRAL MEXICO FROM THE ATLANTIC BASIN...WHICH IS EXPECTED TO FORCE
TD 15-E ON A GENERAL WEST-NORTHWESTWARD TRACK. ALL OF THE GLOBAL
MODELS AND THE GFDL MODEL AGREE ON THE DEVELOPMENT OF THIS
SYNOPTIC-SCALE STEERING PATTERN...ALBEIT A WEAK FLOW.

THE CYCLONE IS FORECAST TO REMAIN OVER NEAR-29C SSTS FOR ABOUT 72
HOURS AND UNDER MODEST EASTERLY VERTICAL SHEAR CONDITIONS OF 10-15
KT. THEREFORE...GRADUAL INTENSIFICATION IS FORECAST SIMILAR TO THE
SHIPS INTENSITY MODEL. THE OFFICIAL INTENSITY FORECAST IS SLIGHTLY
HIGHER THAN THE SHIPS MODEL AND NEARLY TWICE THE ICON INTENSITY
MODEL FORECAST DUE TO THE DEPRESSION EXPECTED TO MOVE SLOWER THAN
THE BAMM MODEL IS INDICATING...WHICH WAS THE MODEL USED TO GENERATE
THE SHIPS MODEL OUTPUT. THE SLOWER FORECAST TRACK IS EXPECTED TO
KEEP THE SYSTEM OVER WARMER WATER AND IN WEAKER SHEAR CONDITIONS
LONGER THAN THE BAMM-SHIPS MODEL IS FORECASTING.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/0300Z 13.6N  99.4W    30 KT
 12HR VT     04/1200Z 13.7N  99.7W    35 KT
 24HR VT     05/0000Z 13.9N 100.3W    40 KT
 36HR VT     05/1200Z 14.3N 101.3W    45 KT
 48HR VT     06/0000Z 14.7N 102.5W    55 KT
 72HR VT     07/0000Z 15.3N 103.7W    65 KT
 96HR VT     08/0000Z 16.0N 105.0W    65 KT
120HR VT     09/0000Z 17.0N 106.5W    65 KT
 
$$
FORECASTER STEWART