000 WTPZ41 KNHC 182034 TCDEP1 TROPICAL DEPRESSION COSME DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP062007 200 PM PDT WED JUL 18 2007 QUIKSCAT DATA AT 1521Z INDICATED 30-35 KT WINDS NEAR THE CENTER OF COSME. SINCE THEN...THE ASSOCIATED CONVECTION HAS DIMINISHED SIGNIFICANTLY AND IT IS LIKELY THAT THE WINDS HAVE DECREASED SLIGHTLY. BASED ON THIS...COSME IS DOWNGRADED TO A 30 KT TROPICAL DEPRESSION. 12 FT SEAS RADII WILL BE INCLUDED IN THIS ADVISORY SINCE THE CYCLONE WAS STILL OF STORM STRENGTH A FEW HOURS AGO. THE INITIAL MOTION REMAINS 275/11. THE LOW/MID-LEVEL RIDGE NORTH AND NORTHWEST OF COSME REMAINS THE PRIMARY STEERING MECHANISM...AND THE LARGE-SCALE MODELS CONTINUE TO MAINTAIN THIS RIDGE THROUGH 5 DAYS. COSME SHOULD THUS CONTINUE GENERALLY WESTWARD THROUGH THE FORECAST PERIOD AS SHOWN BY ALL GUIDANCE. THE GFDL AND HWRF HAVE SHIFTED SOUTH OF THEIR PREVIOUS FORECASTS...WITH ONLY THE BAM MODELS AND LBAR NOW CALLING FOR THE CENTER TO PASS OVER THE ISLAND OF HAWAII. THE NEW FORECAST TRACK IS AGAIN SHIFTED SLIGHTLY SOUTHWARD AND IS DOWN THE MIDDLE OF THE DYNAMICAL MODEL GUIDANCE. THE INTENSITY FORECAST IS STILL PROBLEMATIC. IN THE SHORT TERM... COSME SHOULD REACH GRADUALLY INCREASING SEA SURFACE TEMPERATURES IN ABOUT 30 HR IN A LIGHT SHEAR ENVIRONMENT. THIS SUGGEST THE POSSIBILITY OF SOME STRENGTHENING...ASSUMING THAT THE SYSTEM DOES NOT DISSIPATE FROM LACK OF CONVECTION BEFORE THEN. AFTER 72 HR... COSME SHOULD REACH SIGNIFICANTLY WARMER WATER AND QUITE POSSIBLY SIGNIFICANT VERTICAL WIND SHEAR...AS FORECAST BY THE NOGAPS... UKMET...AND ECMWF MODELS. BASED ON THIS...THE INTENSITY FORECAST WILL CALL FOR COSME TO PERSIST AS A DEPRESSION FOR 72 HR...THEN WEAKEN TO A REMNANT LOW DUE TO SHEAR. SINCE THE GFS STILL FORECASTS LESS SHEAR THAN THE OTHER MODELS AND THERE IS STILL A POSSIBILITY COSME COULD TRACK SOUTH OF THE AREA OF STRONG SHEAR... THE INTENSITY FORECAST AFTER 72 HR REMAINS LOW CONFIDENCE. THIS IS THE LAST ADVISORY ON COSME FROM THE NATIONAL HURRICANE CENTER. FUTURE ADVISORIES WILL BE ISSUED BY THE CENTRAL PACIFIC HURRICANE CENTER IN HONOLULU HAWAII. FORECAST POSITIONS AND MAX WINDS INITIAL 18/2100Z 15.0N 140.1W 30 KT 12HR VT 19/0600Z 15.2N 142.0W 30 KT 24HR VT 19/1800Z 15.7N 144.9W 30 KT 36HR VT 20/0600Z 16.2N 148.0W 30 KT 48HR VT 20/1800Z 16.7N 151.4W 30 KT 72HR VT 21/1800Z 17.5N 157.5W 30 KT 96HR VT 22/1800Z 18.0N 163.0W 25 KT...DISSIPATING 120HR VT 23/1800Z 18.0N 168.0W 20 KT...REMNANT LOW $$ FORECASTER BEVEN