000 AXNT20 KNHC 140606 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 106 AM EST Tue Nov 14 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 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...SPECIAL FEATURES... A 1010 mb low pressure center is near 32N31W, about 390 nm to the SSW of the Azores. A surface trough extends from the low center to 30N31W 27N33W 24N36W. Rainshowers are possible from 25N northward between 30W and 40W. The low center is supported aloft by a middle level to upper level cyclonic circulation center, that is near 33N31W. Precipitation: widely scattered to scattered moderate and isolated strong rainshowers from 30N to 36N between 26W and 32W. This low pressure center has a medium chance of becoming a subtropical cyclone during the next couple of days as it moves to the NE, before upper-level winds become unfavorable. Expect near gale-force winds during the next day or two. ...ITCZ/MONSOON TROUGH... The monsoon trough passes through coastal sections of Sierra Leone near 08N13W to 07N17W. The ITCZ continues from 07N17W to 08N24W, 04N35W, 04N49W, and into Brazil, and French Guiana near 03N53W. Precipitation: scattered strong from 04N to 06N between 09W and 12W. scattered moderate to isolated strong from 04N to 09N between 14W and 20W. isolated moderate elsewhere from 13N southward from 60W eastward. Upper level SW wind flow covers the Atlantic Ocean to the S and SE of the line from 26N15W to 23N30W to 13N45W to 07N56W. Broken to overcast multilayered clouds and possible rainshowers are in this same area. ...DISCUSSION... THE GULF OF MEXICO... An upper level trough passes through central Florida into the SE corner of the area. The trough supports a cold front, that passes through 32N77W to the Florida coast near 30N81W, to 29N85W in the Gulf of Mexico. Upper level SW wind flow is moving from the Yucatan Channel, toward south Florida and beyond the Bahamas. The upper level SW wind flow is part of a larger-scale area of anticyclonic wind flow that is extending from the Caribbean Sea, across the Greater Antilles, into the Atlantic Ocean. Precipitation: isolated moderate from 23N to 24N between 87W and 89W. rainshowers are possible in parts of the Straits of Florida, south Florida, and toward the Bahamas. A surface ridge passes through NE Texas, through the deep south of Texas, to Mexico near 24N99W, into the Isthmus of Tehuantepec of southern Mexico. The current pressure gradient is expected to relax somewhat by Wednesday. The wind speeds will be decreasing, into gentle-to- moderate breezes, and gentle southerly return flow re- establishing itself across the NW waters. THE CARIBBEAN SEA... Large-scale upper level anticyclonic wind flow spans the area. A ridge extends from the SW corner of the area, beyond 30N69W in the Atlantic Ocean. A surface trough extends from a 1005 mb low pressure center that is near 11N78W, to 15N81W, to 20N81W, near the Cayman Islands. Precipitation: widely scattered to isolated strong rainshowers from 73W westward, including in the Windward Passage, along the coast of Colombia. A second surface trough extends from Cuba near 21N77W, across the central Bahamas, to 26N74W in the Atlantic Ocean. Precipitation: widely scattered moderate to isolated strong from 20N northward from 63W westward. Upper level anticyclonic wind flow is moving on top of this area, with the upper level ridge that runs from the SW corner of the Caribbean Sea to 30N69W in the Atlantic Ocean. Moderate to fresh tradewinds prevail, and they are expected to persist through Tuesday. Global models indicate a broad and stretched out area of surface low pressure developing from the waters NE of Cuba to Jamaica and into the SW Caribbean Tuesday night into Wednesday quickly moving E-NE and merging with a frontal boundary in the SW North Atlc Wednesday night into Thursday. ...HISPANIOLA... Widely scattered moderate to isolated strong rainshowers are in the Windward Passage. Surface observations are not reporting rainshowers. Cumulonimbus clouds are being reported in Port-au- Prince in Haiti. Upper-level W wind flow is moving across the area. Low-level moisture convergence continues to be maximized across the region within E-SE tradewinds. This overall pattern will persist through Thursday with precipitation expected to increase during the next 24 to 48 hours. THE ATLANTIC OCEAN... A surface trough is along 23N25W 20N27W 16N28W. Upper level SW wind flow covers the Atlantic Ocean to the S and SE of the line from 26N15W to 23N30W to 13N45W to 07N56W. Broken to overcast multilayered clouds and possible rainshowers are in this same area. ar 32N32W. For additional information please visit http://www.hurricanes.gov/marine $$ MT