ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Potential Tropical Cyclone Two-E Discussion Number 1 NWS National Hurricane Center Miami FL EP022023 1000 PM CDT Wed Jun 28 2023 The system the NHC has been monitoring off of Mexico is starting to show signs of organization based on geostationary satellite imagery. An elongated area of low pressure has formed with convection gradually building over the past several hours. The current subjective satellite estimate from TAFB give the disturbance a T-number of 1.5, suggesting that it is close to becoming a tropical cyclone, but it has not quite become one yet. The initial intensity is estimated to 25 kt for this advisory. The disturbance is moving northwestward at about 10 kt. This general motion is expected to continue as the system moves along the southwest periphery of a mid-level trough centered over the southern United States. At the end of the forecast period, the system is expected to turn west-northwestward in the low-level flow. There is increased uncertainty in this track forecast due to the uncertainty in the location of where the storm will ultimately form. A more northern position will likely bring the potential cyclone closer to Mexican coast. The NHC track forecast is closest to the simple consensus aid. The potential tropical cyclone is embedded in an environment conducive for intensification, with low vertical wind shear and high mid-level moisture. The system is also over warm sea surface temperatures of more than 30 degrees C. Model guidance is in fairly good agreement that the disturbance will become a tropical cyclone in the next day or so and steadily strengthen over the next few days. Atmospheric and ocean conditions are expected to become more hostile day 4 and beyond, likely leading to weakening. The official intensity forecast is closest to the LGEM model. KEY MESSAGES: 1. A Tropical Storm Warning is in effect along the southwestern coast of Mexico from Punta Maldonado to Lazaro Cardenas, and tropical storm conditions should begin within this area by Thursday afternoon. 2. Locally heavy rainfall of 3 to 5 inches with maximum amounts of 7 inches, is expected across southern Mexico from the state of Oaxaca westward to the state of Jalisco. These rains could lead to localized flash flooding. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 13.5N 96.8W 25 KT 30 MPH...POTENTIAL TROP CYCLONE 12H 29/1200Z 14.3N 98.3W 30 KT 35 MPH...TROPICAL CYCLONE 24H 30/0000Z 15.4N 100.1W 35 KT 40 MPH 36H 30/1200Z 16.6N 101.9W 45 KT 50 MPH 48H 01/0000Z 17.9N 103.7W 55 KT 65 MPH 60H 01/1200Z 19.3N 105.6W 65 KT 75 MPH 72H 02/0000Z 20.6N 107.2W 65 KT 75 MPH 96H 03/0000Z 22.2N 110.2W 50 KT 60 MPH 120H 04/0000Z 22.5N 112.6W 30 KT 35 MPH $$ Forecaster Bucci/Pasch NNNN