Tropical Depression NINE-E

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TROPICAL DEPRESSION NINE-E DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092009
200 PM PDT SUN AUG 09 2009
 
ALTHOUGH TINY...THE AREA OF LOW PRESSURE LOCATED ABOUT 800 N MI
SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA HAS QUICKLY
ATTAINED SUFFICIENT CONVECTIVE BANDING DURING THE MORNING HOURS TO
WARRANT DVORAK INTENSITY ESTIMATES OF T2.0 FROM TAFB AND SAB AT
1800 UTC.  THEREFORE...ADVISORIES ARE BEING INITIATED AT THIS TIME.

THE DEPRESSION CURRENTLY LIES ON THE SOUTHERN PERIPHERY OF A
MID-LEVEL RIDGE WHICH EXTENDS WEST-SOUTHWESTWARD FROM NORTHERN
MEXICO...AND ABOUT 800 N MI SOUTH-SOUTHEAST OF A MID- TO
UPPER-LEVEL AREA OF LOW PRESSURE.  THE LOW IS EXPECTED TO MOVE
SLOWLY WESTWARD OVER THE NEXT FEW DAYS AND ALLOW THE RIDGE TO ALSO
BUILD WESTWARD...STEERING T.D. NINE-E ON A GENERAL WEST TO
WEST-NORTHWESTWARD COURSE OVER THE NEXT FIVE DAYS.  OF THE GLOBAL
MODELS...THE GFS AND UKMET DO NOT INITIALIZE A VORTEX ASSOCIATED
WITH THE SYSTEM...AND THE ECMWF AND NOGAPS ONLY INITIALIZE A WEAK
VORTEX...PROBABLY DUE TO ITS SMALL SIZE.  AS A RESULT...THIS FIRST
FORECAST HAS A HIGH LEVEL OF UNCERTAINTY.  THE OFFICIAL FORECAST
LEANS HEAVILY ON THE GFDL AND HWRF HURRICANE MODEL TRACKS AND DOES
NOT SHOW THE DEPRESSION GAINING MUCH LATITUDE.

THE SMALL SIZE OF THE DEPRESSION WILL LIKELY CAUSE IT TO HAVE QUICK
CHANGES IN INTENSITY...MUCH LIKE THAT OBSERVED IN HURRICANE CARLOS
EARLIER THIS SEASON.  HOWEVER...NONE OF THE INTENSITY MODELS SHOW
MUCH STRENGTHENING...AND THE OFFICIAL FORECAST IS AT THE HIGH END
OF THE GUIDANCE CLOSE TO THAT SHOWN IN THE SHIPS AND GFDL MODELS. 
IT WOULD NOT SURPRISE ME AT ALL IF T.D. NINE-E WAS TO STRENGTHEN
MORE THAN INDICATED IN THE OFFICIAL FORECAST.  SEVERAL OF THE
GLOBAL MODELS SHOW ANOTHER SYSTEM FORMING NEAR 138W IN ABOUT THREE
TO FOUR DAYS AND EVENTUALLY ABSORBING THE DEPRESSION...AND THIS
MIGHT BE CONTRIBUTING TO THE WEAKENING SHOWN IN THE MODELS AT DAYS
4 AND 5.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/2100Z 14.0N 120.3W    30 KT
 12HR VT     10/0600Z 14.2N 121.4W    35 KT
 24HR VT     10/1800Z 14.5N 123.0W    40 KT
 36HR VT     11/0600Z 14.9N 124.9W    45 KT
 48HR VT     11/1800Z 15.5N 127.0W    50 KT
 72HR VT     12/1800Z 16.0N 131.0W    50 KT
 96HR VT     13/1800Z 16.0N 135.0W    45 KT
120HR VT     14/1800Z 16.0N 139.0W    40 KT
 
$$
FORECASTER BERG
 
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