000 AXNT20 KNHC 012359 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 759 PM EDT Mon May 1 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. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the coast of Africa near 12N16W to 06N19W. The Intertropical Convergence Zone extends from 05N20W to 02N30W to the coast of South America near 01S46W. A surface trough is analyzed from 09N27W to 03N28W. Scattered moderate convection is observed from 06S-03N between 27W-41W. ...DISCUSSION... GULF OF MEXICO... A mid to upper-level low centered over the upper Midwest is lifting northward with the trailing trough beginning to shear out over the north-central Gulf. This is providing limited support for a weakening cold front that as of 2100 UTC extends from the Florida Big Bend near 30N84W to 27N87W where it became stationary through 23N91W to the Bay of Campeche. Broken to overcast multi- layered cloudiness with embedded showers were noted within 180-240 Nm east of the front, extending over Florida and Georgia. A surface ridge extends across Florida to 28N85W and was beginning to bridge the front to a 1016 MB surface high near 29N93W. Surface observations showed light winds across most of the Gulf with winds shifting from the S and SE east of the front to northerly or light and variable west of the front. Increasing SE return flow was developing along the Texas coast. The cold front is expected to move east during the next 24 hours while dissipating. SE return flow will spread across the Gulf west of 90W as another area of low pressure develops across Texas by midweek and moves northeast across the lower Mississippi River valley. CARIBBEAN SEA... Most of the Caribbean basin is under the influence of dry and relatively stable W to NW flow aloft on the eastern periphery of an upper-level anticyclone centered over Nicaragua near 12N87W. A well defined upper level low centered near the Turks and Caicos has an associated upper level trough extending through the Windward Passage/western Haiti to a base near 17N75W. Upper level diffluence was noted E of the upper low over the southwestern N Atlantic across Puerto Rico and eastern Hispaniola. Extensive cloudiness and scattered showers and isolated thunderstorms were noted over both areas. Locally heavy rainfall resulted in flooding across Puerto Rico over the past few days. The 1200 UTC rawinsonde from San Juan showed precipitable water values close to 2.00 inches with deep moisture to 350 mb. A surface trough extends across the EPAC to near Costa Rica and supports isolated moderate convection south of 12N between 78W-82W. Scatterometer data depicts moderate to fresh trades across the basin. Over the next 24 hours a surface trough is forecast to develop east of the upper- level low in the vicinity of Hispaniola and move west across the western Atlantic through Thursday. ...HISPANIOLA... Currently, scattered showers and thunderstorms are occurring across eastern Haiti and the Dominican Republic and northeastward over the adjacent Atlantic Ocean. This activity is due to a middle to upper- level low centered in the vicinity of the Turks and Caicos. Although the 1200 UTC rawinsonde from Santo Domingo showed precipitable water values of 1.63 inches with modest moisture to 600 mb, indication are the amount of moisture is forecast to increase over the next 24 hours as a surface trough develops in the vicinity of the island and moves west across the west Atlantic through Thursday with the potential for localized heavy rainfall and flooding. ATLANTIC OCEAN... A vast anticyclone and ridging covers most of the western Atlantic with the main anticyclone centered near 28N52W. A mid to upper- level low centered near the Turks and Caicos is producing abundant cloudiness with embedded showers and isolated thunderstorms affecting the area south of 25N between 65W-71W. At the surface a ridge anchored by a 1025 mb high centered near Bermuda dominates the western Atlantic. Farther east, a middle to upper- level trough over the central Atlantic supports a cold front that extends into the area from 31N44W to 28N55W to 30N65W. Broken to overcast low clouds with isolated embedded showers are possible within 240 NM east of the front N of 28N. The remainder of the eastern Atlantic is under the influence of a surface ridge anchored by a 1023 mb high centered well north of the area near 39N11W. Over the next 24 hours a surface trough will develop in the vicinity of Hispaniola and the southern Bahamas and move west across the west Atlantic through Thursday. For additional information please visit http://www.hurricanes.gov/marine $$ Cobb