000 AXNT20 KNHC 010452 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1252 AM 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 0000 UTC surface analysis and satellite imagery through 0415 UTC. ...SPECIAL FEATURES... A vigorous middle to upper level low is centered over the mid- Mississippi River valley this evening supporting a cold front extending into the Gulf of Mexico from the SE Louisiana coast near 29N90W S-SW to 24N93W to the southern Mexico coast near 18N93W. Scattered showers and tstms are occurring N of 27N between 86W and the frontal boundary. In addition to the convection...near gale to gale force N-NW winds are occurring offshore of Veracruz and are expected to persist through the overnight hours. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the Africa coast near 10N14W to 04N21W. The Intertropical Convergence Zone axis extends from 04N21W to the Equator near 35W. A surface trough is analyzed from 01N22W to 09N21W and likely very weak energy that propagated off of western Africa the middle of last week. Widely scattered moderate convection is from S of 06N between 17W-42W. ...DISCUSSION... GULF OF MEXICO... As mentioned in the Special Features section above...a vigorous middle to upper level low centered over the central CONUS supports a cold front extending from SE Louisiana near 30N90W to 24N93W to the southern Mexico coast near 18N93W. Aside from the near gale to gale force winds occurring offshore of Veracruz...strong northerly winds are noted generally S of 27N west of the front. To the east of the front...primarily gentle to moderate S-SE winds prevail. Most ongoing convection is associated with a squall line extending from the far western Florida panhandle to the cold front near 28N90W. The northern portion of the cold front will continue sweeping eastward while the southern extent will begin to stall Monday into Tuesday. High pressure will build in behind the front across the western Gulf supporting moderate to occasional fresh E-NE winds through mid-week. Otherwise by Tuesday night... moderate E-SE winds will increase to fresh levels across the western waters into Wednesday as an area of low pressure develops across Texas and moves E-NE across the lower Mississippi River valley the second half of the week. CARIBBEAN SEA... Most of the Caribbean basin is under the influence of dry and relatively stable NW flow aloft on the eastern periphery of an upper level anticyclone centered over southern Honduras near 13N87W. However...middle to upper level troughing is noted in the vicinity of 20N69W N of Hispaniola. This troughing is generating area of widely scattered showers and isolated tstms N of 16N between 60W-70W. The troughing aloft is expected to remain nearly stationary N of Hispaniola through Tuesday night and then weaken and shift N as the aforementioned ridging moves eastward over western portions of the basin. Otherwise...moderate to fresh trades prevail and are expected to persist through Tuesday night as high pressure remains anchored to the N across the SW North Atlc region. ...HISPANIOLA... Currently widely scattered showers and isolated tstms are occurring across eastern portions of the island and the adjacent coastal waters generally E of 70W. This activity is due in large part to a middle to upper level trough focused in the vicinity of 20N69W. The troughing aloft is expected to remain nearly stationary through Tuesday night with higher probability of precipitation and convection remaining in the forecast through early Wednesday until the upper level feature is expected to weaken and move northward. ATLANTIC OCEAN... Much of the SW North Atlc is under the influence of a surface ridge anchored by a 1026 mb high centered W of Bermuda near 32N69W. One exception to the ridge is an area of widely scattered showers and isolated tstms occurring S of 24N between 60W-70W in association with an middle to upper level trough noted on water vapor imagery in the vicinity of 20N69W. This feature is expected to remain nearly stationary through Tuesday night and then gradually weaken into Wednesday. Cloudiness and probability of precipitation and convection are forecast to increase for the Turks and Caicos...along with portions of the SE Bahamas the next few days. Farther east...a middle to upper level trough over the central North Atlc supports a cold front that remains to the N of the discussion area...however pre-frontal troughing dips S to 29N between 40W-58W. Isolated showers are possible across this area as the front continues to approach 30N. The remainder of the eastern Atlc is under the influence of a surface ridge anchored by a 1024 mb high centered near 32N27W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN