ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM Tropical Depression Three-E Discussion Number 1 NWS National Hurricane Center Miami FL EP032024 800 AM MST Wed Jul 31 2024 Over the last few hours, the convective organization has improved with the area of low pressure we have been monitoring a few hundred miles off the southwestern coast of Mexico. First-light visible imagery from a GOES-West meso-sector over the storm show the development of organized curve banding, with low-level cloud motions also now suggesting the presence of closed cyclonic flow. This improved convective structure was also seen in an earlier 1040 UTC SSMIS microwave pass. In addition, the latest set of subjective Dvorak intensity estimates were both at T2.5/35 kt from both SAB and TAFB. All these data suggest that the system has become a tropical cyclone, and advisories are being initiated at this time. The initial intensity for this advisory is set at 30 kt, a little under the Dvorak estimates given the lower objective estimates and earlier scatterometer data. The initial estimated motion is off to the west-northwest at 295/12-kt. This motion is expected to continue with a gentle turn more westward over the next few days as the system becomes primarily steered by a deep-layer ridge located over the southwestern United States. Towards the end of the forecast period, there could be a bit more of a weakness in this ridge on its western extent, potentially allowing the system to turn more poleward again. The initial track forecast in general sticks close to the consensus aids TVCE and HCCA, which favor a track that is in between the operational GFS and ECMWF tracks, but slightly in favor of the latter. Intensity-wise, TD3-E might be our first system in the East Pacific to last longer than a couple of days, with most of the guidance suggesting intensification into the weekend. SHIPS guidance from both the GFS and ECMWF suggest the shear will remain low (less than 15 kt) while sea-surface temperatures underneath the cyclone remain in the 29-30 C range over the next few days. Such a favorable environment could favor significant intensification once an inner-core becomes established. Interestingly, the regional-hurricane model guidance, while showing intensification, do not currently forecast rapid intensification. The first NHC intensity forecast shows more gradual intensification for the next day or so, followed by a somewhat faster rate, peaking the system as a Category 1 hurricane in 72 h, on the high end of the intensity guidance. Towards the end of the forecast, the tropical cyclone should begin to move over cooler ocean waters, with gradual weakening expected to begin around day 4 or 5. FORECAST POSITIONS AND MAX WINDS INIT 31/1500Z 15.1N 107.2W 30 KT 35 MPH 12H 01/0000Z 15.7N 108.9W 35 KT 40 MPH 24H 01/1200Z 16.3N 110.9W 40 KT 45 MPH 36H 02/0000Z 16.7N 112.9W 50 KT 60 MPH 48H 02/1200Z 17.0N 115.0W 60 KT 70 MPH 60H 03/0000Z 17.0N 117.1W 70 KT 80 MPH 72H 03/1200Z 17.1N 119.0W 75 KT 85 MPH 96H 04/1200Z 18.0N 121.5W 70 KT 80 MPH 120H 05/1200Z 18.5N 123.5W 60 KT 70 MPH $$ Forecaster Papin NNNN