000 AXNT20 KNHC 221738 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 138 PM EDT Tue May 22 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... A 1009 mb low pressure center is near 17N87W. A surface trough is along 86W/88W, through the 1009 mb low center, from southern Honduras to the NE coast of the Yucatan Peninsula. Upper level cyclonic wind flow spans the eastern Gulf of Mexico and the NW Caribbean Sea, connected to the trough that has been in place during the last week. Deep layer tropical moisture continues to stream northward on the eastern edge of the upper trough. Precipitation: scattered moderate to isolated strong rainshowers are in the Caribbean Sea from 13N northward between Jamaica and 86W. isolated moderate rainshowers are in the Gulf of Mexico from 90W eastward. isolated moderate to locally strong rainshowers are elsewhere from 13N southward from 70W westward. Strong upper level winds and dry air aloft are expected to limit organization during the next few days. Some gradual subtropical or tropical development is possible late this week, while the system moves slowly northward into the central or eastern Gulf of Mexico. Locally heavy rainfall is possible in western Cuba, the Cayman Islands, and much of Florida during the next several days. Please refer to forecasts and charts that are issued by your local weather office for more information on the heavy rain threat. The chance for tropical storm formation during the next 48 hours is low. ...TROPICAL WAVES... A tropical wave is along 38W/39W, S of 11N, moving W 10 to 15 knots. This wave is embedded in a sharp 700 mb trough. No significant precipitation accompanies this tropical wave. A weak tropical wave is along 65W/66W from 17N southward in the eastern Caribbean Sea, south of Puerto Rico and the Virgin Islands, moving westward 10 to 15 knots. No significant precipitation accompanies this tropical wave. It is likely that the wave will become diffuse late today. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Liberia near 06N10W to 03N15W. The ITCZ continues from 03N15W to 03N26W to 01N36W. Precipitation: widely scattered moderate to isolated strong rainshowers 04N southward from 21W eastward, and from 03N to 07N between 20W and 39W. isolated moderate rainshowers are elsewhere from 10N southward from 60W eastward. ...DISCUSSION GULF OF MEXICO... Please read the Special Features section for more details about the upper level trough and related surface weather features from the Gulf of Mexico into the NW Caribbean Sea. One upper level trough is in place already in the eastern half of the Gulf of Mexico. That feature is the topic of discussion for the SPECIAL FEATURES section. A second upper level trough, from NE-to-SW, is moving from Texas into west central Gulf of Mexico. isolated moderate rainshowers are in the waters from 90W westward. A surface ridge in the northern Gulf coast will shift eastward through mid week. A developing low pressure center is forecast to emerge off the coast of the Yucatan Peninsula on Thursday night. The low pressure center will move N slowly. It will approach the N central Gulf coast by Saturday evening, bringing fresh to strong winds and building seas to the eastern Gulf. CARIBBEAN SEA... Please read the Special Features section for more details about the upper level trough and related surface weather features from the Gulf of Mexico into the NW Caribbean Sea. Upper level cyclonic wind flow covers the area from Hispaniola eastward. The cyclonic wind flow is moving around a trough, that passes through the Atlantic Ocean, toward the coast of Venezuela along 65W/66W. A surface Ridge along 30N will maintain fresh to locally strong trade winds in the central Caribbean Sea, and strong winds and sea heights to 9 feet will affect the NW coast of Colombia through Friday. The low pressure center, that is just to the east of Belize, will move N into the Gulf of Mexico late on Thursday. Fresh to strong winds will develop between the trough and the Atlantic Ocean high pressure center that is to the south of Cuba, on Friday. ATLANTIC OCEAN... Please read the Special Features section for more details about the upper level trough and related surface weather features from the Gulf of Mexico into the NW Caribbean Sea. An E-to-W oriented ridge along 30N will support gentle to moderate SE winds north of 22N, and moderate to fresh trade winds south of 22N into the middle of the week. The wind speeds will pulse to strong N of Hispaniola mainly at night. The winds and sea heights will diminish slightly by Friday, as the ridge shifts eastward. SE winds may increase near Cay Sal Bank and the Florida Straits starting on Friday, as the NW Caribbean Sea low pressure center moves northward through the Gulf of Mexico. For additional information please visit http://www.hurricanes.gov/marine $$ MT