000 WTPZ44 KNHC 012048 TCDEP4 TROPICAL STORM DALILA DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013 200 PM PDT MON JUL 01 2013 THE INNER CORE OF DALILA HAS BECOME A LITTLE BETTER ORGANIZED DURING THE PAST FEW HOURS. DVORAK INTENSITY ESTIMATES FROM TAFB...SAB... AND UW-CIMSS HAVE CONVERGED TO A CONSENSUS T-NUMBER OF 3.5...SO THE INITIAL INTENSITY HAS BEEN RAISED TO 55 KT. ALTHOUGH DALILA IS LOCATED IN A SYNOPTIC ENVIRONMENT CONSISTING OF VERY WARM SEA SURFACE TEMPERATURES AND FAIRLY LOW VERTICAL WIND SHEAR...A PRONOUNCED DRY SLOT HAS DEVELOPED IN THE SOUTHEASTERN QUADRANT OF THE STORM WHICH SUGGESTS THAT DRY AIR MAY BE ENTRAINING INTO THE CIRCULATION. MOST OF THE INTENSITY GUIDANCE NOW FORECASTS DALILA TO BECOME A HURRICANE WITHIN THE NEXT 24 HOURS. HOWEVER...THE SPREAD AMONG THE MODELS IS HIGH...ESPECIALLY REGARDING HOW QUICKLY THE DRY AIR AND DECREASING SEA SURFACE TEMPERATURES WILL CAUSE THE CYCLONE TO WEAKEN IN THE 3 TO 5 DAY TIME PERIOD. THE OFFICIAL FORECAST HAS NOT CHANGED SUBSTANTIALLY FROM THE PREVIOUS FORECAST...AND NOW LIES VERY NEAR THE INTENSITY CONSENSUS THROUGH THE ENTIRE FORECAST. THE CENTER OF DALILA HAS BEEN OBSCURED BY A CENTRAL DENSE OVERCAST FEATURE. MICROWAVE-BASED CENTER FIXES SUGGEST THAT THE CYCLONE HAS BEGUN TO TURN AWAY FROM THE MEXICAN COAST...AND THE INITIAL MOTION IS 295/6. WHILE THE REASONING BEHIND THE TRACK FORECAST IS UNCHANGED...THE SPREAD IN THE TRACK GUIDANCE REMAINS VERY HIGH. THE ECMWF FORECASTS A NEARLY DUE SOUTH TRACK...WHILE THE GFS FORECASTS A GENERALLY WESTWARD TRACK THROUGH 120 HOURS. THESE DISCREPANCIES APPEAR TO BE RELATED TO THE STRENGTH AND DEPTH OF THE CYCLONE VORTEX. THE OFFICIAL FORECAST LEANS TOWARD THE GFS SOLUTION WHICH HAS A STRONGER VORTEX...MORE IN LINE WITH THE NHC INTENSITY FORECAST. GIVEN THE UNCERTAINTY IN THE INTENSITY FORECAST...THE DEGREE OF UNCERTAINTY IN THE TRACK FORECAST IS ALSO VERY HIGH. SINCE DALILA HAS BEGUN TO MOVE AWAY FROM MEXICO...THE TROPICAL STORM WATCHES AND WARNINGS ALONG THE COAST OF THAT COUNTRY HAVE BEEN DISCONTINUED. HOWEVER...THE OUTER RAINBANDS OF THE TROPICAL CYCLONE WILL LIKELY CONTINUE TO IMPACT THE SOUTHWEST COAST OF MEXICO THROUGH TONIGHT. FORECAST POSITIONS AND MAX WINDS INIT 01/2100Z 17.9N 106.5W 55 KT 65 MPH 12H 02/0600Z 18.2N 107.2W 65 KT 75 MPH 24H 02/1800Z 18.4N 107.8W 65 KT 75 MPH 36H 03/0600Z 18.5N 108.5W 60 KT 70 MPH 48H 03/1800Z 18.5N 109.1W 55 KT 65 MPH 72H 04/1800Z 18.5N 110.0W 50 KT 60 MPH 96H 05/1800Z 18.5N 112.0W 45 KT 50 MPH 120H 06/1800Z 18.5N 115.0W 35 KT 40 MPH $$ FORECASTER PASCH/ZELINSKY