000 AXNT20 KNHC 191049 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 549 AM EST Tue Dec 19 2017 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 0600 UTC surface analysis and satellite imagery through 1045 UTC. ...SPECIAL FEATURES... ...Gale Warning in the Caribbean Sea... Pulsing nocturnal easterly winds to gale-force are expected again near the coast of Colombia during the overnight tonight and early morning hours on Tuesday, particularly from 10N to 13N between 74W and 78W. Expect sea heights to range from 10 to 14 ft. Wind will diminish below gale-force by Tuesday afternoon, and are expected to reach again minimal gale-force at night. Thereafter, strong to near-gale force winds will persist in the area each night this week. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough enters the Atlantic Ocean near 09N14W and continues to 05N30W. The ITCZ extends from 05N30W to northeast Brazil near 02N50W. Scattered moderate convection is noted within about 30 nm on either side of these boundaries between 10W-31W. ...DISCUSSION... ...GULF OF MEXICO... Surface ridging prevails across the whole basin, anchored by a 1025 mb high centered over northwest Florida near 28N83W. Scatterometer data depicts gentle to moderate easterly winds across the basin. Patchy fog has been reported this morning over the northern Gulf mainly north of 27N and across the Florida Peninsula. These conditions will dissipate by late morning. The ridge is forecast to persist through Tuesday night. A weak cold front will reach the coast of Texas on Wednesday, and stall across the northern Gulf by Thursday before moving north as a warm front on Thursday night. A stronger cold front will reach the northwest Gulf on Friday. Fresh southerly return flow is expected across the western Gulf ahead of the front. ...CARIBBEAN SEA... Please refer to the Special Features section for details about the gale warning near the coast of Colombia. The most recent scatterometer data indicated fresh to strong winds over the central Caribbean and across the Windward Passage. Moderate to fresh winds prevail elsewhere. An altimeter pass indicated seas of 11 ft over the southwest Caribbean in association with the strong trades. Patches of low-level moisture embedded in the trade wind flow are observed on satellite imagery, more concentrated over the central Caribbean. Broad mid-level anticyclonic wind flow and strong subsidence dominates the entire Caribbean Sea with fair weather. Little change is expected during the next 24-48 hours. ...HISPANIOLA... A broad mid to upper-level high is covering the Caribbean Sea and very dry air aloft supporting mostly stable conditions across the island. However, shallow moisture embedded in the trade wind flow will move across Hispaniola to produce isolated to scattered passing showers through the next 24 hours. ...ATLANTIC OCEAN... A deep layer trough in the central Atlantic is supporting a frontal system analyzed as a cold front from 31N37W to 27N44W, then the front becomes stationary from that point to 20N69W. Mainly low-level clouds with scattered showers are along the cold front. Strong high pressure building west of the front will prevail over the west Atlantic through mid-week. This pattern will keep South Florida mostly dry and warm through the weekend. East of the front, the Azores high extends across the eastern Atlantic. For additional information please visit http://www.hurricanes.gov/marine $$ ERA