000 AXNT20 KNHC 130024 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 705 PM EST Thu Jan 12 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURES... A strong pressure gradient between lower pressure across South America and a ridge anchored across the SW North Atlc is generating near gale to gale force winds in the SW Caribbean Sea. Gale conditions are expected to pulse during the late night and early morning hours through Sunday. Expect on Fri 13/0600 UTC from 10N-13N between 74W-78W NE winds 30-35 KT with seas 11- 15 ft. This gale will last six hours. Expect on Sat 14/0600 UTC from 10N-13N between 74W-78W NE winds 30-35 KT with seas 11-14 ft. This gale will again last six hours. See latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 10N14W to 02N22W. The Intertropical Convergence Zone axis extends from 02N22W to 00N30W to 01N42W to the coast of South America near 01S49W. Scattered moderate convection is from 01N-03N between 19W-22W. Isolated moderate convection is from 01N-05N between 38W-52W. ...DISCUSSION... GULF OF MEXICO... 10-20 kt E to SE surface return flow is over the Gulf of Mexico maintaining warm temperatures. The entire Gulf is void of precipitation. An upper level high is centered over central Florida near 29N81W. Very strong subsidence covers the entire Gulf. This overall synoptic pattern is expected to persist through the remainder of the week and into the weekend. The next front is not expected until Tuesday night into Wednesday along the Texas coast. CARIBBEAN SEA... Gale to near gale conditions are along the coast of N Colombia. See above. A shear line extends from E of St. Lucia near 14N60W to 13N70W to the coast of Nicaragua near 12N84W. Scattered showers are within 60 nm of the shear line. Elsewhere, radar imagery shows scattered showers over Puerto Rico advecting in from the Atlantic. Hispaniola has similar conditions especially over the upper elevations. In the upper levels, an upper level ridge is over the Caribbean Sea with axis along 70W. Strong subsidence cover the entire Caribbean. Expect showers along the shear line to persist for the next 24 hours becoming diffuse Sat. ...HISPANIOLA... Fresh to strong NE winds prevail across the island and adjacent coastal waters. This wind field is due to a relatively strong pressure gradient between the NW Caribbean and the Atlantic low near 23N54W. Scattered showers are over the northern portions of the island especially over higher elevations. Expect showers to continue as the NE flow persists through the remainder of the week into the weekend. ATLANTIC OCEAN... A 1032 mb high is centered over the W Atlantic near 40N58W. A ridge axis extends SW to N Florida. A 1009 mb occluded low is centered near 23N54W that is supported aloft by an upper level low nearly collocated with the surface feature near 25N54W. Another 1010 mb triple point surface low is centered near 25N52W. A cold front extends S-SW from this low to 20N52W to E of the Lesser Antilles near 14N60W. Near gale force winds are occurring NE of the surface lows. Expect in 24 hours for a 1010 mb surface low to be located near 22N52W with a surface trough extending S to 17N56W with showers. The remainder of the frontal system will dissipate. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa