000 AXNT20 KNHC 180603 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 102 AM EST Wed Dec 18 2019 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... A cold front extends from 29N83W to 18N92W. Latest ASCAT data shows Gale to storm force winds over portion of the western Gulf from 18N-20N and west of 95W. This strong gale force winds will continue through Wednesday afternoon in the southwestern Gulf of Mexico, mainly south of 22N and west of 93.5W. Elsewhere behind the front, winds of 25-30 kt will continue through tonight, with frequent gusts to gale force south of 26N and west of 87W. Seas of 11-17 ft will occur over portions of the southwestern Gulf of Mexico through Wednesday morning. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for further details. ...MONSOON TROUGH/ITCZ... The ITCZ passes through the coast of Sierra Leone near 08N13W to 01N29W to 01N47W. Scattered moderate convection is seen from 01N- 04N between 14W-38W. Scattered showers are seen near Brazil and French Guiana extending 300 nm east offshore. GULF OF MEXICO... See the section above for details on the Gale Warning in the Gulf of Mexico. Since early this morning and latest ASCAT data shows fresh to strong northerly winds behind the front across central and western portion of the Gulf of Mexico. Gale force winds are also seen over the western Gulf north of 20N and west of 94W. A squall line extends from 26N83W to 30N80W ahead of the front. Scattered moderate isolated strong convection is seen over the NE Gulf of Mexico from North central Florida SE to the Yucatan Channel. Convection is being enhanced by upper level diffluence. A surface trough over the Yucatan Peninsula is also inducing scattered moderate with isolated strong convection over the northern Yucatan Peninsula, Yucatan Channel. The squall line will continue racing east-southeast across the rest of the eastern Gulf through late tonight. The front will move southeast across the Gulf and extend from Tampa Bay Florida to central Yucatan tonight, before moving southeast of the area Wed. Northerly gale force winds and very large seas will prevail behind the front, mainly W of 90W, through late Wed. Winds and seas will diminish over the central and western Gulf Thu and Thu night. Strong NE to E winds will continue over the Straits of Florida after the frontal passage Thu through Fri night. Low pressure may develop over the eastern Gulf Fri night and move across Florida this weekend. A heavy rainfall event is expected now through Wed for the Mexican states of Chiapas, Tabasco southern portions of Campeche. Currently, rains have already begun over much of the Yucatan Peninsula. In Mexico, the maximum rainfall amounts may range from 4 to 6 inches. The most intense rainfall is expected on Wed through Thu morning, These rains will likely cause localized flooding and possible mudslides. CARIBBEAN SEA... A surface trough over the Yucatan Peninsula is inducing scattered moderate with isolated strong convection over the Yucatan Channel as well as the east coast of the Yucatan Peninsula, the Gulf of Honduras and Belize. Elsewhere in the NW Caribbean, scattered showers extend to beyond the Cayman Islands, mainly north of 16N between 79W-85W. In the far SW Caribbean, the east Pacific monsoon trough is inducing scattered moderate with isolated strong convection south of 11N between 73W-84W, including over Colombia and Panama. Scattered light to moderate showers are seen over Puerto Rico and Hispaniola. The ASCAT pass from late Tuesday morning shows fresh to locally strong winds across the eastern and central Caribbean, east of 81W, and light to moderate winds across the SW and NW portion. High pressure northeast of the region will maintain fresh to strong trade winds and building seas from the tropical north Atlantic west of 55W to the south central Caribbean through Sat. A strong cold front will move through the Yucatan Channel late Wed, then across the far northwest Caribbean before stalling and weakening from central Cuba to central Honduras by late Thu. Fresh to strong northerly winds will accompany the front. Looking ahead, another front may move across the southern Gulf of Mexico and approach the northwest Caribbean by late Sat, but the precise timing remains uncertain at this time. Heavy rain is also expected to affect northern and central Guatemala, much of Belize, and northwestern Honduras tonight through Thu. ATLANTIC OCEAN... A cold front across the Southeast Plains continues to move SE across Florida tonight. A pre-frontal squall line extends from Jacksonville to Clearwater Florida. Another line of tstorms ahead of that extends over the western Atlantic from near 28N79W to 31N74W. Expect these pre-frontal thunderstorms to continue moving eastward through tonight, extending between 75W and the east coast of Florida. The bulk of the moderate to strong storms will remain north of 27N. Further east, a cold front extends from 31N34W to 28N52W, then stalls to 29N82W. Scattered showers are seen along and 180 nm SE of the front. High pressure over the area will continue to slide eastward through Wed in response to a strong cold front currently over the southeastern U.S. This cold front will move off the southeastern U.S. coast late tonight, reach from near 31N70W to western Cuba on Wed night, and then from 27N65W across the central Bahamas to central Cuba on Thu night. Strong north to northeast winds and building seas are expected across much of the forecast waters following frontal passage. The front will gradually stall over the central waters Fri and Fri night. Looking ahead, fresh to strong easterly winds may persist Sat across much of the western part of the area and NW Bahamas to northeast Florida as low pressure develops in the Gulf of Mexico and tracks in a general east to northeast direction. Exact timing and location of this low remains uncertain. $$ NATIONAL HURRICANE CENTER