ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM Tropical Storm Bonnie Discussion Number 1 NWS National Hurricane Center Miami FL EP042022 1000 AM CDT Sat Jul 02 2022 Radar data from the Nicaraguan Weather Service in Las Nubes indicate that Bonnie has moved offshore from extreme southern Nicaragua and becomes one of the rare tropical cyclones to cross from the Atlantic Basin into the eastern Pacific Basin. The center of circulation remains well-defined after crossing southern Nicaragua last night, and satellite data during the last several hours indicate that deep convection remains active near the center of the storm. Given the robust structure apparent on radar and satellite, the initial intensity is held steady at 35 kt for this advisory, despite the land interactions during the past 12 hours or so. Bonnie is moving due west at 270/14 kt. The primary steering influence throughout the forecast period is a deep-layer ridge located north of the storm, which is expected to cause Bonnie to track west-northwestward and remain offshore and roughly parallel to the coast of Central America and Mexico. Track guidance is in good agreement throughout the forecast period, and the official forecast is very similar to the consensus track aids and the prior forecast. Although the strongest winds are expected to remain offshore, interests in coastal El Salvador, Guatemala, and southwestern Mexico should continue to monitor Bonnie's track for the next few days, as any northward track adjustments could require tropical storm watches for portions of this coastline. While the well-defined structure indicates that some strengthening is possible in the next day or so, sea surface temperatures (SSTs) are only marginally conducive for intensification and confined to a relatively shallow depth. For this reason, intensification is forecast to occur slowly for the next 24 hours until Bonnie reaches warmer waters in about 36 hours, after which the rate of intensification is forecast to increase. Similar to the previous forecast, Bonnie is expected to reach hurricane strength in about three days, and the intensity forecast is near the center of the guidance envelope. In association with Bonnie crossing into the eastern Pacific, product headers for Bonnie have changed to eastern Pacific headers beginning with this advisory, with the ATCF identifier changing from AL022022 to EP042022. KEY MESSAGES: 1. Heavy rainfall across portions of Nicaragua and Costa Rica will continue today. Life-threatening flash flooding and mudslides are expected. 2. Tropical storm conditions are expected along the Pacific coasts of Costa Rica and Nicaragua within the Tropical Storm Warning areas for the next several hours. FORECAST POSITIONS AND MAX WINDS INIT 02/1500Z 11.2N 86.4W 35 KT 40 MPH 12H 03/0000Z 11.3N 88.3W 35 KT 40 MPH 24H 03/1200Z 11.7N 90.7W 40 KT 45 MPH 36H 04/0000Z 12.5N 93.6W 45 KT 50 MPH 48H 04/1200Z 13.4N 96.6W 55 KT 65 MPH 60H 05/0000Z 14.3N 99.6W 60 KT 70 MPH 72H 05/1200Z 15.1N 102.5W 65 KT 75 MPH 96H 06/1200Z 16.0N 107.5W 70 KT 80 MPH 120H 07/1200Z 16.6N 111.7W 75 KT 85 MPH $$ Forecaster Hogsett/Cangialosi NNNN