000 WTPZ42 KNHC 212031 TCDEP2 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