Tropical Depression TWO-E
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TROPICAL DEPRESSION TWO-E DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP022009
200 PM PDT SUN JUN 21 2009
SPIRAL BANDING HAS INCREASED DURING THE DAY AROUND THE AREA OF LOW
PRESSURE SOUTHWEST OF ACAPULCO...AND THE LOW-LEVEL CENTER APPEARS
TO HAVE BECOME SUFFICIENTLY WELL-DEFINED TO DESIGNATE THE SYSTEM AS
A TROPICAL CYCLONE. DVORAK T-NUMBERS FROM TAFB AND SAB WERE 2.0 AND
2.5...RESPECTIVELY...AND THE CURRENT INTENSITY IS SET AT 30 KT.
THIS INTENSITY IS CORROBORATED BY A COUPLE OF RECENT SHIP REPORTS
IN THE AREA. SEA SURFACE TEMPERATURES WILL REMAIN WARM ALONG THE
FORECAST TRACK OVER THE NEXT 3 TO 4 DAYS...BUT THE SHIPS MODEL
PROJECTS THAT EASTERLY WIND SHEAR WILL INCREASE TO AROUND 20 KT
WITHIN THE NEXT DAY OR SO. THE LATEST RUN OF THE HWRF MODEL IS MORE
AGGRESSIVE THAN THE GFDL IN STRENGTHENING THE CYCLONE. CURIOUSLY...
THIS IS THE REVERSE OF WHAT WAS INDICATED BY THE MODEL RUNS FROM 12
HOURS EARLIER. DUE TO THESE UNCERTAINTIES...THE OFFICIAL FORECAST
SHOWS ONLY GRADUAL INTENSIFICATION AND DOES NOT BRING THE CYCLONE
TO HURRICANE STATUS. WEAKENING SHOULD OCCUR BY DAYS 4 AND 5 ONCE
THE SYSTEM MOVES INTO A MORE STABLE ENVIRONMENT OVER COOLER WATERS.
NONE OF THE GLOBAL MODELS INITIALIZED THIS SYSTEM PARTICULARLY
WELL...AND THIS IS LIKELY AFFECTING THEIR RESPECTIVE FORECAST
TRACKS. THE UKMET AND ECMWF MOVE THE DEPRESSION NORTHWARD TOWARDS
THE MEXICAN COAST...BUT THE SYSTEM IS CURRENTLY MOVING WESTWARD.
THE GFDL SHOWS VERY LITTLE MOTION DURING THE NEXT 24 TO 48
HOURS...BUT THIS ALSO DOES NOT SEEM CONSISTENT WITH THE SYSTEM'S
CURRENT MOTION. THEREFORE...THE OFFICIAL FORECAST TRACK RELIES ON
EXTRAPOLATION AND CLIMATOLOGY FOR THE FIRST 24 HOURS OR SO...THEN
COMES MORE IN LINE WITH A CONSENSUS OF THE GFS...GFDL...HWRF...AND
UKMET. AFTER 72 HOURS...THE SUBTROPICAL RIDGE IS EXPECTED TO BUILD
WESTWARD OVER MEXICO AND STEER THE CYCLONE ON A MORE WESTWARD
COURSE AWAY FROM LAND.
DUE TO THE EXPECTED SLOW MOTION OF THE SYSTEM OVER THE NEXT DAY OR
SO...A TROPICAL STORM WATCH IS NOT REQUIRED FOR THE SOUTHWESTERN
COAST OF MEXICO AT THIS TIME. HOWEVER...INTERESTS IN THE REGION
SHOULD CONTINUE TO MONITOR THE PROGRESS OF THE CYCLONE DUE TO THE
HIGHER-THAN-AVERAGE UNCERTAINTY IN THE FORECAST TRACK.
FORECAST POSITIONS AND MAX WINDS
INITIAL 21/2100Z 14.7N 101.7W 30 KT
12HR VT 22/0600Z 14.8N 102.2W 40 KT
24HR VT 22/1800Z 15.2N 102.8W 50 KT
36HR VT 23/0600Z 15.8N 103.4W 55 KT
48HR VT 23/1800Z 16.9N 104.2W 60 KT
72HR VT 24/1800Z 19.5N 107.0W 60 KT
96HR VT 25/1800Z 21.0N 111.0W 45 KT
120HR VT 26/1800Z 21.0N 116.0W 30 KT
$$
FORECASTER BERG/PASCH
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