Tropical Depression FIFTEEN-E

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TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152006
200 AM PDT MON OCT 09 2006
 
A SMALL MASS OF DEEP CONVECTION HAS PERSISTED NEAR AND MOSTLY TO THE
SOUTH OF THE LOW-LEVEL CENTER FOR THE PAST SEVERAL HOURS...AND
UNTIL VERY RECENTLY THE COLDEST TOPS WERE LESS THAN -80 DEGREES
CELSIUS.  DVORAK INTENSITY ESTIMATES AT 06 UTC WERE 30-35 KT. 
SINCE THE CONVECTIVE TOPS HAVE BEEN ON A SLIGHT WARMING TREND...THE
ADVISORY INTENSITY REMAINS 30 KT.  UNFORTUNATELY...THE DEPRESSION
FELL SQUARELY WITHIN THE GAP BETWEEN QUIKSCAT SWATHS AT ABOUT 01
UTC AND 03 UTC...SO THERE IS NO WIND DATA FROM ANYWHERE NEAR THE
CENTER OF THE DEPRESSION.  THE TROPICAL CYCLONE APPEARS TO HAVE A
FAIRLY SHORT WINDOW OF OPPORTUNITY IN WHICH TO STRENGTHEN. 
SOUTHWESTERLY WIND SHEAR SHOULD INCREASE SUBSTANTIALLY DURING THE
NEXT COUPLE OF DAYS...AND THE UNDERLYING SEA SURFACE TEMPERATURE
ALONG THE FORECAST TRACK WILL DECREASE FROM THE CURRENT 28C TO
ABOUT 26C DURING THAT SAME PERIOD.  THE NEW OFFICIAL INTENSITY
FORECAST IS ADJUSTED SLIGHTLY DOWNWARD AND SHOWS A PEAK AT 40
KT...CLOSE TO A BLEND OF THE SHIPS AND GFDL GUIDANCE.  THE CYCLONE
IS FORECAST TO WEAKEN SUBSTANTIALLY BEFORE NEARING THE BAJA
CALIFORNIA PENINSULA IN A FEW DAYS.

THE INITIAL MOTION IS ABOUT THE SAME AS BEFORE...335/8.  THE
DEPRESSION IS MOVING NORTH-NORTHWESTWARD AROUND THE WESTERN EDGE OF
A RATHER WEAK MID-LEVEL RIDGE CENTERED OVER SOUTHERN MEXICO.  THE
CYCLONE SHOULD TURN NORTHEASTWARD IN 24-36 HOURS AS IT ROUNDS THE
RIDGE AND BECOMES EMBEDDED IN A DEEP SOUTHWESTERLY STEERING CURRENT
TO THE SOUTH OF A LARGE CUTOFF LOW OVER SOUTHERN CALIFORNIA. 
HOWEVER...SINCE THE TROPICAL CYCLONE IS EXPECTED TO WEAKEN AND
EVENTUALLY BECOME A SHALLOW SYSTEM AFTER IT TURNS NORTHEASTWARD...
IT WILL PROBABLY NOT MOVE TOO QUICKLY.  IN FACT...THE NEW OFFICIAL
TRACK FORECAST IS SLOWER THAN THE PREVIOUS ADVISORY TO BE IN BETTER
AGREEMENT WITH MOST OF THE MODEL GUIDANCE.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/0900Z 15.3N 117.6W    30 KT
 12HR VT     09/1800Z 16.3N 118.1W    35 KT
 24HR VT     10/0600Z 17.6N 118.2W    40 KT
 36HR VT     10/1800Z 18.7N 117.8W    40 KT
 48HR VT     11/0600Z 19.6N 117.2W    35 KT
 72HR VT     12/0600Z 21.0N 115.5W    30 KT
 96HR VT     13/0600Z 22.5N 113.5W    25 KT...REMNANT LOW
120HR VT     14/0600Z 24.0N 111.5W    20 KT...REMNANT LOW
 
$$
FORECASTER KNABB
 
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