000 WTNT43 KNHC 091442 TCDAT3 Tropical Storm Julia Discussion Number 13 NWS National Hurricane Center Miami FL AL132022 1000 AM CDT Sun Oct 09 2022 Julia continues to move westward across Nicaragua with a well-defined circulation and deep convection persisting near the center. The terrain of southern and central Nicaragua is not as rugged as areas farther north in Central America, and Julia is probably only gradually weakening while it crosses land. Based on a typical decay rate, and interpolating from the previous forecast, Julia is now estimated to be a 60-kt tropical storm. Strong ridging over the Gulf of Mexico continues to propel the storm quickly westward (270 degrees) at about 13 kt, and that motion should continue today, with Julia's center expected to move off the Pacific coast of Nicaragua by this evening. By tonight and Monday, Julia is forecast to turn toward the west-northwest and move very close to and parallel to the Pacific coasts of Honduras, El Salvador, and Guatemala. The model trackers lose Julia in a day or two and instead show a potential track farther offshore by keying in on a broader circulation farther west that is associated with an ongoing Gulf of Tehuantepec gap wind event. However, global model fields, in particular the GFS and ECWMF, show Julia's smaller circulation more closely hugging the Pacific coast of Central America, and the updated NHC track forecast more closely follows that scenario. Additional weakening is expected today while Julia continues moving over land, but the cyclone should still be at tropical storm strength when it moves offshore this evening. In keeping with the GFS and ECMWF solutions, Julia's contracting circulation is forecast to weaken further over the Pacific waters, coincident with an increase in easterly shear. Based on the latest forecast, Julia is expected to weaken to a tropical depression on Monday and then dissipate by Monday night while moving close to the coast of Guatemala. Regardless of Julia's track and future status as a tropical cyclone, the evolving weather pattern is likely to lead to heavy rains over Central America and southern Mexico for several days, which could cause life-threatening flash floods and mudslides, especially in areas of mountainous terrain. Since Julia's low-level circulation is expected to survive its passage across Nicaragua, the cyclone will retain the same name when it moves into the eastern Pacific basin. The intermediate advisory at 100 PM CDT (1800 UTC) will be issued under the same Atlantic product headers as before. However, now that all coastal watches and warnings are located along the Pacific coast of Central America, product headers will change to eastern Pacific headers beginning with the next complete advisory at 400 PM CDT (2100 UTC), with the ATCF identifier changing from AL132022 to EP182022. Key Messages: 1. Julia is forecast to remain as a tropical storm while it moves across Nicaragua today and reaches the adjacent Pacific waters this evening. Tropical storm warnings are in effect along the Pacific coasts of Nicaragua, Honduras, and El Salvador to account for the likelihood of tropical-storm-force winds in those areas later today through Monday. Tropical-force-winds are also possible on Monday along the Pacific coast of Guatemala, where a tropical storm watch is in effect. 2. Life-threatening flash flooding and mudslides are expected across portions of Central America Sunday and Monday. Flash flooding is anticipated across the Isthmus of Tehuantepec in Mexico early this week. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 12.4N 85.4W 60 KT 70 MPH...INLAND 12H 10/0000Z 12.5N 87.5W 45 KT 50 MPH...OVER WATER 24H 10/1200Z 13.2N 89.6W 40 KT 45 MPH 36H 11/0000Z 14.0N 91.9W 30 KT 35 MPH 48H 11/1200Z...DISSIPATED $$ Forecaster Berg