000 WTPZ44 KNHC 020831 TCDEP4 TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042008 200 AM PDT WED JUL 02 2008 SATELLITE IMAGES SHOW THAT THE TROPICAL CYCLONE IS SLOWLY BECOMING BETTER ORGANIZED. THERE ARE VERY COLD CLOUD TOPS WITHING DEVELOPING BANDS OVER THE SOUTHERN AND WESTERN PORTIONS OF THE SYSTEM. HOWEVER THE BANDS DO NOT YET WRAP SUFFICIENTLY AROUND THE CENTER TO CLASSIFY THE CYCLONE AS A TROPICAL STORM VIA THE DVORAK TECHNIQUE. A QUIKSCAT PASS FROM A FEW HOURS AGO SUGGESTED THAT THE SYSTEM WAS CLOSE TO TROPICAL STORM INTENSITY EVEN THOUGH AN AMBIGUITY ANALYSIS OF THE SCATTEROMETER DATA SHOWED A BROAD AND NOT PARTICULARLY WELL-DEFINED CENTER. I AM HOLDING OFF ON UPGRADING FOUR-E ON THIS ADVISORY...BUT SINCE THE CURRENT ENVIRONMENT APPEARS MODESTLY FAVORABLE WITH WARM WATERS AND MODERATE EASTERLY SHEAR...THE CYCLONE WILL PROBABLY STRENGTHEN INTO A TROPICAL STORM TODAY. WITHIN 36-48 HOURS...THE INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT THE SYSTEM WILL BEGIN WEAKENING AS IT NEARS MARGINAL SEA SURFACE TEMPERATURES. THIS IS ALSO INDICATED BY THE OFFICIAL FORECAST...WHICH IS SIMILAR TO THE PREVIOUS ONE AND IN GOOD AGREEMENT WITH THE SHIPS GUIDANCE. SINCE THE CENTER IS ILL-DEFINED THERE IS A SOMEWHAT GREATER THAN USUAL UNCERTAINTY IN THE INITIAL LOCATION AND MOTION. THE LATTER IS ESTIMATED TO BE 315/6. THE DEPRESSION IS ON THE SOUTHERN SIDE OF A MID-LEVEL RIDGE THAT EXTENDS FROM THE SOUTHWESTERN U.S. INTO MEXICO. GLOBAL MODELS SHOW SOME WEAKENING OF THE RIDGE OVER THE NEXT FEW DAYS. CONSEQUENTLY THE FORWARD MOTION OF THE TROPICAL CYCLONE IS LIKELY TO SLOW DURING THE FORECAST PERIOD. THE OFFICIAL TRACK FORECAST IS A LITTLE TO THE RIGHT OF THE PREVIOUS NHC FORECAST AND CLOSE TO A CONSENSUS OF THE GFS...HWRF...GFDL AND U.K. MET OFFICE FORECAST TRACKS THROUGH 72 HOURS. AT DAYS 4 AND 5...THE SYSTEM IS LIKELY TO TURN WESTWARD AS IT WEAKENS AND FOLLOWS THE LOWER-TROPOSPHERIC FLOW. FORECAST POSITIONS AND MAX WINDS INITIAL 02/0900Z 16.6N 107.4W 30 KT 12HR VT 02/1800Z 17.2N 107.9W 35 KT 24HR VT 03/0600Z 17.9N 108.6W 40 KT 36HR VT 03/1800Z 18.6N 109.4W 45 KT 48HR VT 04/0600Z 19.1N 110.1W 40 KT 72HR VT 05/0600Z 19.8N 111.5W 35 KT 96HR VT 06/0600Z 20.5N 113.0W 25 KT 120HR VT 07/0600Z 20.5N 114.0W 20 KT...REMNANT LOW $$ FORECASTER PASCH