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| #201712 (Received by flhurricane at: 11:05 PM 18.Jul.2008) TCDAT3 TROPICAL DEPRESSION THREE DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032008 1100 PM EDT FRI JUL 18 2008 OVER THE PAST SEVERAL HOURS...CONVECTION ASSOCIATED WITH THE AREA OF LOW PRESSURE OFF THE GEORGIA COAST HAS BECOME MORE CONCENTRATED WITH AMPLE MID-LEVEL ROTATION. PERSISTENT NORTHWESTERLY WINDS FROM A SKIDAWAY INSTITUTE OF OCEANOGRAPHY 50 METER TOWER A SHORT DISTANCE WEST OF THE MAIN AREA OF CONVECTION INDICATE THAT THE CIRCULATION HAS BECOME BETTER DEFINED SINCE THIS AFTERNOON. CONSEQUENTLY...ADVISORIES ARE INITIATED ON TROPICAL DEPRESSION THREE. THERE ARE NO INDICATIONS...EITHER FROM COASTAL RADAR OR SURFACE OBSERVATIONS...THAT THE SYSTEM HAS ACQUIRED MUCH IN THE WAY OF STRONG WINDS YET...AND THE INITIAL INTENSITY IS SET AT 25 KT. THE INITIAL MOTION IS ESTIMATED TO BE 040/5. STEERING CURRENTS ARE WEAK...WITH THE DEPRESSION SITTING BETWEEN A MID-LEVEL RIDGE EAST OF THE BAHAMAS AND A WEAKER ONE OVER THE TENNESSEE VALLEY. MODEL GUIDANCE IS IN PRETTY GOOD AGREEMENT THAT A SLOW NORTHEASTWARD MOTION WILL CONTINUE...VERY CLOSE TO THE COAST OF THE CAROLINAS... FOR THE NEXT DAY OR TWO...WITH A GRADUAL ACCELERATION INTO THE WESTERLIES BEFORE THE SYSTEM BECOMES ABSORBED BY THE NEXT MID-LATITUDE SHORT WAVE. THE OFFICIAL FORECAST IS NEAR THE CONSENSUS OF THE TIGHTLY PACKED GUIDANCE...ALTHOUGH I'LL NOTE THAT BOTH THE GFDL AND HWRF HAVE TRACKS THAT ESSENTIALLY STRADDLE THE COASTLINE. BECAUSE THE FORECAST TRACK IS NEARLY PARALLEL TO THE ORIENTATION OF THE COASTLINE...IT IS IMPOSSIBLE TO PINPOINT A POSSIBLE LANDFALL LOCATION AT THIS TIME. THE ENVIRONMENT DOES NOT SEEM CONDUCIVE TO RAPID DEVELOPMENT. THE UPPER-LEVEL WINDS ARE SOMEWHAT DIVERGENT...BUT THERE IS A LOT OF DRY AIR NEARBY OVER THE SOUTHEASTERN UNITED STATES. EXCEPT FOR THE CLIMATOLOGY AND PERSISTENCE MODEL SHIFOR...NONE OF THE INTENSITY GUIDANCE MAKES THE SYSTEM A TROPICAL STORM. HOWEVER...THE SHIPS FORECAST SEEMS TO BE BASED ON SSTS THAT LOOK AT LEAST 1C COOLER THAN WHAT THE COASTAL BUOYS ARE REPORTING RIGHT NOW...SO I'M GOING TO GO A LITTLE ABOVE THAT GUIDANCE AND SHOW JUST ENOUGH STRENGTHENING TO MAKE THE SYSTEM A TROPICAL STORM. THE FORECAST TRACK AND INTENSITIES REQUIRE THE ISSUANCE OF TROPICAL STORM WATCHES AND WARNINGS. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0300Z 31.9N 79.6W 25 KT 12HR VT 19/1200Z 32.4N 79.1W 30 KT 24HR VT 20/0000Z 33.4N 78.0W 35 KT 36HR VT 20/1200Z 34.4N 76.6W 35 KT 48HR VT 21/0000Z 35.5N 75.0W 35 KT 72HR VT 22/0000Z 38.0N 70.5W 35 KT 96HR VT 23/0000Z...ABSORBED $$ FORECASTER FRANKLIN |
