Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 641 PM EST Tue Nov 13 2018 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURES... ...Storm Warning in the Gulf of Mexico... A strong cold front is currently moving eastward across the Gulf of Mexico. The front extends from 30N84W to 25N88W to 20N91.5W to 17N92.5W as of 2100 UTC. Gale force winds are occurring west of the front mainly west of 90W. Storm force winds are occurring offshore of Veracruz. Winds are forecast to diminish below gale force for areas north of 26N later tonight. The front will reach from near Cedar Key, Florida to the northeast Yucatan Peninsula by Wed morning. Winds and seas will gradually subside through late week as the front sweeps southeast of the area by late Thu. Gentle to moderate northerly flow will cover the Gulf Fri. Refer to the High Seas Forecast product under AWIPS/WMO headers HSFAT2/FZNT02 KNHC for more details. ...TROPICAL WAVES... A Caribbean Sea tropical wave extends its axis along 63W from 14N southward, moving W around 15 kt. Scattered showers and isolated thunderstorms are affecting portions of the Windward Islands, Trinidad, northeastern Venezuela and waters from 09N-15N between 57W-65W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the W coast of Senegal near 14N17W to 12N20W to 09N24W. The ITCZ extends from 09N24W to 04N29W to 02N49W. Scattered moderate convection is within 180 nm north and within 480 nm south of the monsoon trough. Scattered moderate convection is within 180 nm north and within 120 nm south of the ITCZ between 24W-44W. Scattered moderate convection is within 360 nm north of the ITCZ between 44W-49W. GULF OF MEXICO... A strong cold front extends across the basin, with gale and storm force winds prevailing over portions of the western Gulf of Mexico. See the Special Features section above for more details on the gale force winds. Overcast low clouds with scattered showers cover the Gulf of Mexico west of the front. Elsewhere, isolated showers and thunderstorms are east of the front over the Yucatan Peninsula and Gulf of Mexico waters south of 23N. CARIBBEAN SEA... A surface trough is over the Leeward and Virgin Islands from 23N60W to 16N64W. An upper-level low is located over the Virgin Islands and Puerto Rico near 18N65W, and is interacting with the surface trough to enhance convection in the area. Scattered moderate convection is occurring from 16N-22N between 58W-68W, including near and over portions of the Leeward and Virgin Islands as well as Puerto Rico. Scattered showers and thunderstorms are also occurring near and over Hispaniola. This system continues to have a low chance of tropical cyclone formation during the next 48 hours. This system is expected to bring locally heavy rainfall to portions of the Leeward Islands, Virgin Islands, and Puerto Rico over the next couple of days as it moves generally westward to west-northwestward. In the southwest Caribbean, scattered moderate to strong convection is noted south of 12N between 73W-85W, including over northern Colombia, Panama, Costa Rica, and southern Nicaragua due to the East Pacific monsoon trough. At this time, strong convection is particularly active over northern Colombia north of 6.5N and over the western half of Panama. High pressure north of the area is supporting fresh trade winds over most of the region. The trough across the Virgin Islands extending NE into the adjacent Atlantic will move across Puerto Rico through late tonight, and then across Hispaniola Wed. The combination of this trough and the tropical wave over the southeast Caribbean will spread enhanced showers and thunderstorms westward through the east-central Caribbean, reaching Hispaniola and the ABC Islands by late Wednesday and early Thursday. Strong northerly winds and building seas will follow a cold front entering the Yucatan Channel late Wed. Expect enhanced shower and thunderstorm activity with periods of heavy rain for portions of the Yucatan Peninsula, Belize, Honduras and the adjacent waters of the northwest Caribbean through early Fri. Fresh northerly winds and seas to 8 ft will spread across the northwest Caribbean into Fri behind the front, then diminish Fri into Sat as the front stalls and weakens from eastern Cuba to eastern Honduras. ATLANTIC OCEAN... Scattered showers and thunderstorms are noted north of the northwest Bahamas between 76W and the east coast of Florida. This activity is enhanced by the front to the northwest of the area and the daytime heating over Florida, with strong upper-level southwesterlies pushing this activity into the western Atlantic. The surface trough over the Virgin Islands and associated convection that extends into the Atlantic northward to 22N between 58W-68W is discussed above in the Caribbean Sea section. The tail-end of a frontal boundary extends from 32N39W to 31N43W. A line of scattered showers ahead of the front is occurring within 30 nm either side of a line from 32N29W to 29N35W to 27N40W to 25.5N44W. The line is moving southeastward around 20 kt. A 1025 mb surface high is centered over the Atlantic near 30N44W. High pressure over the NW Atlantic will shift ESE ahead of a cold front moving off the northeast Florida coast tonight. The front will reach from near 31N74W to the central Bahamas and central Cuba late Thu night into Fri. Meanwhile a trough across the NE Caribbean and adjacent Atlantic will move westward across Puerto Rico through tonight, across Hispaniola Wed, and through the southern Bahamas by late Thu. Low pressure may form along the trough as it reaches the Bahamas then recurve northward Fri to the east of the central Bahamas ahead of the cold front, then move north of the area Sat as the cold front reaches from Bermuda to eastern Cuba. For additional information please visit http://www.hurricanes.gov/marine