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| #1111091 (Received by flhurricane at: 10:54 AM 08.Oct.2022) TCDAT3 Tropical Storm Julia Discussion Number 9 NWS National Hurricane Center Miami FL AL132022 1100 AM EDT Sat Oct 08 2022 Air Force Reserve reconnaissance data indicate that Julia is not a vertically stacked tropical cyclone. The plane first made an initial center fix to the north of the main area of deep convection and found that the central pressure had fallen to 994 mb. About an hour later, a second center fix was made three tenths of a degree farther south near the deep convection, although the lowest pressure there was only about 998 mb. The center has been placed in between the two fixes, hedging toward the lower pressure to the north. Julia`s initial intensity is set at 55 kt based on the lowering of the central pressure and unanimous satellite classifications of T3.5. So far, the aircraft has measured peak 850-mb flight-level winds of 50 kt and reliable SFMR winds around 45 kt, so it`s assumed the plane has not directly sampled the area of highest winds. Despite the uncertainty in Julia`s initial position, it`s clear that the storm continues to move quickly westward with an estimated motion of 270/18 kt. With strong ridging to the north, a continued fast westward trajectory is expected during the next couple of days, which should bring Julia`s center inland over Nicaragua by early Sunday morning. If Julia`s center survives the passage over Central America, it could move just offshore of or along the Pacific coasts of Nicaragua, Honduras, and El Salvador Sunday night and Monday. It still appears that there is about 15 kt of northwesterly or northerly shear affecting Julia, but model guidance indicates this should abate and then turn out of the east-northeast later today and tonight. Therefore, further strengthening is anticipated, and Julia is forecast to become a hurricane later today. It`s important to keep in mind that Julia could have a higher intensity when it reaches the coast of Nicaragua than what is explicitly shown, since in this forecast landfall would occur between the 12- and 24-hour forecast times. In fact, SHIPS guidance suggests the intensity could be in the 75-80 kt range at 18 hours, which mirrors what was shown in the previous NHC forecast. Due to Julia`s more southern and faster track, there is increasing global model support that the cyclone will be able to maintain a well-defined center and circulation while it crosses Central America, and it could also still be at tropical storm intensity when it reaches the Pacific side of Central America. However, even if it survives the crossing, most of the guidance shows the circulation becoming more diffuse or dissipating over the Pacific waters in 2 to 3 days. Based on the updated NHC forecast, and to account for the possibility of tropical-storm-force winds along the Pacific coast of Central America, tropical storm warnings and watches have been issued for the Pacific coasts of Nicaragua, Honduras, and El Salvador. Regardless of Julia`s track and existence as a tropical cyclone, the evolving set up is likely to lead to heavy rains over Central America for several days, which could cause life-threatening flash floods and mudslides, especially in areas of mountainous terrain. Key Messages: 1. Julia is forecast to strengthen into a hurricane later today, and a Hurricane Warning is in effect for portions of the Nicaragua coast and the islands of Providencia and San Andres. Hurricane-force winds and a dangerous storm surge are expected in areas where the core of the system crosses the islands later today and moves onshore in Nicaragua early Sunday morning. 2. Life-threatening flash flooding and mudslides are expected across portions of Central America this weekend. Flash flooding is possible across the Isthmus of Tehuantepec in Mexico early next week. 3. There is an increasing chance that Julia could remain as a tropical storm while it moves across Central America, and tropical storm warnings and watches have been issued along the Pacific coasts of Nicaragua, Honduras, and El Salvador to account for the possibility of tropical-storm-force winds in those areas late Sunday and Monday. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 12.6N 79.9W 55 KT 65 MPH 12H 09/0000Z 12.5N 81.9W 70 KT 80 MPH 24H 09/1200Z 12.5N 84.3W 65 KT 75 MPH...INLAND 36H 10/0000Z 12.7N 86.9W 40 KT 45 MPH...INLAND 48H 10/1200Z 13.2N 89.5W 30 KT 35 MPH...OVER WATER 60H 11/0000Z 13.7N 91.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 11/1200Z...DISSIPATED $$ Forecaster Berg |
