Tropical Depression TWELVE-E

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TROPICAL DEPRESSION TWELVE-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP122013
200 AM PDT THU SEP 05 2013

SCATTEROMETER DATA INDICATE THAT THE LOW PRESSURE AREA OFF THE
SOUTHWEST COAST OF MEXICO HAS BECOME BETTER DEFINED OVERNIGHT...
AND RECENT SATELLITE IMAGERY SHOWS THAT THE SYSTEM HAS ENOUGH
ORGANIZED DEEP CONVECTION FOR IT TO BE CLASSIFIED AS A TROPICAL
CYCLONE.  THE INITIAL WIND SPEED IS SET AT 30 KT...WHICH IS
SUPPORTED BY THE SCATTEROMETER DATA AND RECENT DVORAK
CLASSIFICATIONS.

THE INITIAL MOTION IS A HIGHLY UNCERTAIN 305 DEGREES AT 5 KT.  THE
DEPRESSION IS EXPECTED TO MOVE NORTHWESTWARD AT A SLIGHTLY FASTER
FORWARD SPEED AROUND THE SOUTHWESTERN PORTION OF A MID-LEVEL RIDGE
OVER NORTHERN MEXICO.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON
THIS SCENARIO.  WHEN THE CYCLONE WEAKENS IN 2 TO 3 DAYS...IT IS
LIKELY TO SLOW DOWN AND BECOME NEARLY STATIONARY WITHIN AN AREA OF
WEAK LOW-LEVEL STEERING CURRENTS.  THE NHC TRACK IS ALONG THE
SOUTHERN EDGE OF THE GUIDANCE ENVELOPE THROUGH 48 HOURS...WHICH 
IS IN GOOD AGREEMENT WITH THE GFS AND ECMWF MODELS.  

THE DEPRESSION IS FORECAST TO REMAIN OVER WARM WATER AND IN LOW
SHEAR DURING THE NEXT COUPLE OF DAYS.  HOWEVER...THE SPRAWLING
NATURE AND LACK OF AN INNER CORE SUGGEST THAT ANY INTENSIFICATION
SHOULD BE GRADUAL.  IN 36 TO 48 HOURS...THE CYCLONE SHOULD BEGIN TO
INGEST STABLE AIR TO THE WEST OF THE BAJA PENINSULA.  THIS SHOULD
CAUSE THE SYSTEM TO WEAKEN AND BECOME A REMNANT LOW WITHIN 3 TO 4
DAYS.

INTERESTS IN THE SOUTHERN BAJA CALIFORNIA PENINSULA SHOULD MONITOR
THE PROGRESS OF THIS SYSTEM.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  05/0900Z 17.6N 106.1W   30 KT  35 MPH
 12H  05/1800Z 18.4N 107.1W   35 KT  40 MPH
 24H  06/0600Z 19.7N 108.5W   40 KT  45 MPH
 36H  06/1800Z 20.8N 109.7W   40 KT  45 MPH
 48H  07/0600Z 21.5N 110.5W   35 KT  40 MPH
 72H  08/0600Z 22.0N 111.0W   25 KT  30 MPH
 96H  09/0600Z 22.0N 111.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  10/0600Z...DISSIPATED
 
$$
FORECASTER BROWN
 
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