000 WTPZ41 KNHC 290250 TCDEP1 TROPICAL DEPRESSION ONE-E DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012008 800 PM PDT WED MAY 28 2008 THE LARGE AREA OF LOW PRESSURE OFF THE COAST OF COSTA RICA HAS BEEN GRADUALLY ACQUIRING ORGANIZATION TODAY. LAST-LIGHT VISIBLE IMAGERY SUGGESTED A REASONABLY WELL-DEFINED SURFACE CIRCULATION...AND THE 00Z DVORAK CLASSIFICATIONS FROM TAFB AND SAB WERE BOTH T2.0... SUGGESTING ENOUGH CONVECTIVE STRUCTURE TO CONSIDER THE SYSTEM A TROPICAL DEPRESSION. THE CONVECTION IS STILL RATHER THIN...CONFINED MOSTLY TO A FEW BANDS WELL AWAY FROM THE CENTER...ALTHOUGH ONE SMALL BAND HAS DEVELOPED CLOSE TO THE CENTER OVER THE PAST HOUR OR TWO. GIVEN THE SPRAWLING NATURE OF THE SYSTEM...THE INITIAL INTENSITY IS SET AT 25 KT... SLIGHTLY BELOW THE DVORAK ESTIMATES. THE INITIAL MOTION IS HARD TO GAUGE...BUT IS ESTIMATED TO BE 010/3. THE DEPRESSION IS LOCATED WITHIN A BROAD CYCLONIC GYRE IN THE LOW TO MID LEVELS...WITH A MID-LEVEL RIDGE TO THE NORTH OF THE DEPRESSION IN THE GULF OF MEXICO. MOST OF THE OBJECTIVE GUIDANCE AGREES ON A GENERALLY NORTHWARD TRACK INITIALLY...WITH A BEND TO THE LEFT OVER THE NEXT DAY OR TWO WITHIN THE GYRE AND TO THE SOUTH OF THE GULF RIDGE. THE OFFICIAL FORECAST IS IN BEST AGREEMENT WITH THE 12Z UKMET AND THE DYNAMICAL MODEL CONSENSUS...TAKING THE SYSTEM INLAND IN ABOUT 24 HOURS. HOWEVER...BECAUSE OF THE ORIENTATION OF THE COASTLINE RELATIVE TO THE FORECAST TRACK...EVEN MODEST TRACK ERRORS COULD RESULT IN LARGE ERRORS IN THE TIMING AND LOCATION OF LANDFALL. WIND SHEAR OVER THE SYSTEM IS FAIRLY LOW BUT THE BEST UPPER-LEVEL SUPPORT IS WELL SOUTH OF THE CENTER...AND ONLY SLOW STRENGTHENING IS EXPECTED UNTIL THE CORE CONVECTION BECOMES BETTER DEFINED. WATERS BENEATH THE CYCLONE ARE WARM...AND THE SHIPS GUIDANCE BRINGS THE DEPRESSION TO STORM STRENGTH IN 24 HOURS. NEITHER THE GFDL...HWRF...OR LGEM MODELS SHOW MUCH DEVELOPMENT...HOWEVER. THE OFFICIAL FORECAST IS IN BEST AGREEMENT WITH THE SHIPS GUIDANCE. THE PRIMARY THREAT WITH THIS SYSTEM WILL BE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES ASSOCIATED WITH HEAVY RAINS...WHICH COULD REACH 20 INCHES OVER THE HIGHER TERRAIN OF CENTRAL AMERICA... ESPECIALLY IN COSTA RICA AND NICARAGUA. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0300Z 10.2N 86.5W 25 KT 12HR VT 29/1200Z 10.8N 86.5W 30 KT 24HR VT 30/0000Z 12.0N 86.8W 35 KT 36HR VT 30/1200Z 13.7N 87.4W 25 KT...INLAND 48HR VT 31/0000Z...DISSIPATED $$ FORECASTER FRANKLIN/RHOME