000 WTPZ41 KNHC 190245 TCDEP1 TROPICAL DEPRESSION ONE-E DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012009 800 PM PDT THU JUN 18 2009 THE DEPRESSION APPEARED TO BE ON THE VERGE OF REACHING TROPICAL STORM STATUS THIS EVENING...BUT OVER THE LAST FEW HOURS THE COLD CLOUD TOPS HAVE SUBSTANTIALLY DIMINISHED AND BANDING FEATURES HAVE BECOME LESS ORGANIZED. AS A RESULT...THE DVORAK T NUMBERS CAME FROM IN TAFB AND SAB LOWER AT 1.5...THOUGH THE CI NUMBERS REMAINED AT 2.0. THUS CURRENT INTENSITY IS KEPT AT 30 KT FOR THIS ADVISORY. A WELL-PLACED AQUA MICROWAVE PASS AT 2026Z ALLOWED FOR A MODERATELY CONFIDENT INITIAL POSITION AND ESTIMATED 20 DEGREE/7 KT INITIAL MOTION. THIS NORTH-NORTHEAST MOTION IS PRIMARILY DRIVEN BY A VERY DEEP TROUGH WEST OF BAJA CALIFORNIA. THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT TWO DAYS IF THE CYCLONE RETAINS DEEP CONVECTION AND A MEDIUM TO DEEP VORTEX. BECAUSE OF THE GFS' ERRONEOUSLY WEAK DEPICTION OF THE VORTEX AT THE INITIAL TIME...THE VERY QUICK NORTHWARD TRACK BY THE GFS AND THE HRWF APPEAR TO BE UNREALISTIC. ADDITIONALLY...THE EGRI TRACKER LOST THE VORTEX FOR SOME REASON...SO THE SLOW NORTHWARD TRACKING UKMI WAS UTILIZED INSTEAD. THE OFFICIAL FORECAST TRACK IS THUS A BLEND OF THE UKMET...ECMWF...AND GFDL MODELS...AND IS SLIGHTLY SLOWER THAN...AND TO THE RIGHT OF...THE PREVIOUS ADVISORY. AN ALTERNATIVE SCENARIO IS FOR THE CYCLONE TO STALL JUST OFF OF THE MEXICO COAST IN ABOUT TWO DAYS IF IT SHEARS APART AND IS SUBSEQUENTLY STEERED BY WEAK LOW LEVEL FLOW. BECAUSE OF THE FARTHER EAST FORECAST TRACK...A TROPICAL STORM WARNING HAS BEEN ISSUED FOR THE ISLAS MARIAS AND THE TROPICAL STORM WATCH HAS BEEN EXTENDED SOUTHWARD ALONG THE MEXICAN COAST. THE DEPRESSION HAS ABOUT A 12 TO 18 HOUR WIND TO INTENSIFY INTO A TROPICAL STORM WHILE THE VERTICAL SHEAR REMAINS LOW. THOUGH THE CYCLONE WILL REMAIN OVER WARM WATER BEFORE MAKING LANDFALL IN MEXICO...THE MODERATE SHEAR AND STABILITY SHOULD PRECLUDE RAPID INTENSIFICATION. ALL OF THE INTENSITY MODEL GUIDANCE SUGGESTS THAT THE CYCLONE WILL BECOME A MINIMAL TROPICAL STORM...AS DOES THIS FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0300Z 18.9N 107.7W 30 KT 12HR VT 19/1200Z 20.2N 107.3W 35 KT 24HR VT 20/0000Z 21.4N 107.1W 35 KT 36HR VT 20/1200Z 22.5N 106.8W 35 KT 48HR VT 21/0000Z 23.7N 106.5W 25 KT...INLAND 72HR VT 22/0000Z...DISSIPATED $$ FORECASTER LANDSEA/BEVEN