000 AXNT20 KNHC 231722 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 122 PM EDT Tue May 23 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...TROPICAL WAVES... A tropical wave extends from 12N21W to 04N22W, moving west about 10 kt. Scattered moderate to isolated strong convection is where the wave meets the Monsoon Trough, mainly from 06N-08N between 20W-26W. The TPW animation shows a decent surge of moisture near the wave axis. A weak tropical wave extends from 13N57W to Suriname near 05N57W. This wave was re-positioned on the 0600 UTC analysis/surface map. The TPW animation shows a modest surge of moisture near the wave axis. A tropical wave is moving across the Caribbean Sea. Its axis extends from eastern Jamaica to 10N76W, moving west at about 15 kt. A small cluster of moderate convection is near the northern end of the wave axis. Another cluster of moderate to isolated strong convection is near the southern end of the wave axis, mainly south of 10N east of 78W to the coast of Colombia. This wave shows up pretty well on the TPW animation. ...ITCZ/MONSOON TROUGH... The Monsoon Trough enters the tropical Atlantic through the west coast of Africa near 11N15W and continues to 06N21W, then resumes west of the tropical wave along 21W/22W at 06N23W to 06N29W. The ITCZ extends from 06N29W to 07N36W to 04N51W. Outside of the convection associated with the aforementioned tropical wave, scattered moderate convection is within about 90 nm N of the ITCZ between 34W and 38W. ...DISCUSSION... GULF OF MEXICO... A cold front has entered the Gulf of Mexico, and currently extends from SE Louisiana to southern Texas. A band of showers and thunderstorms is ahead of the front. This system is forecast to stall over the north-central Gulf tonight. The remainder of the Gulf region is under the influence of a weak ridge, with axis across Cuba and the Yucatan Peninsula. The pressure gradient between the ridge and the frontal boundary is resulting in mainly gentle to moderate E-SE winds over the Gulf. Higher winds are noted just ahead of the front, especially within the area of convection. The most recent scatterometer data reveal the wind shift associated with a thermal trough that usually develops over the Yucatan Peninsula during the evening hours and moves across the SW Gulf during the overnight and early morning hours. A late season cold front will enter the NW Gulf early Wednesday followed by fresh northerly winds. Fresh to strong SW winds are expected ahead of the front on Wednesday. Showers and tstms are also possible ahead of the front. Computer model indicates that these two fronts will merge by late Wednesday. CARIBBEAN SEA... Convection continues to flare up across the SW Caribbean in association with a northern displacement of the monsoon trough. A tropical wave crossing the area is also helping to induce some convective activity in this area. According to computer model guidance, abundant moisture will persist in the SW Caribbean and parts of Central America the remainder of the work week. Moderate to fresh trades are observed across most of the east and central Caribbean based on scatterometer data. These winds are expected to expand across the eastern and central Caribbean on Wednesday as high pressure builds again north of the area. Patches of low level moisture, embedded in the trade wind flow, are observed elsewhere across the region. Aloft, an upper-level trough extends from eastern Cuba to the coast of Nicaragua. Abundant mid-to-upper level moisture in noted on water vapor imagery ahead of this trough. The Saharan Air Layer from UW-CIMSS and visible satellite imagery continue to show the presence of african dust over the Leeward Islands, the UK/US Virgin Islands and Puerto Rico where dry and hazy conditions are prevaling. ...HISPANIOLA... Daytime heating, local sea breezes and mountain upslope lifting will combine with available moisture to produce scattered showers and isolated thunderstorms mainly during the afternoon and early evening hours during the next two days. In fact, computer model suggests limited moisture across the island over the next couple of days. ...ATLANTIC OCEAN... A cold front has entered the forecast area and extends from 31N35W to 25N50W to 26N60W. This front will continue to move SE across the central Atlantic through Thursday before dissipating. High pressure prevails across the remainder of the Atlantic Ocean. A 1025 mb high pressure located near 33N59W follows the front and will move eastward to a postition near 33N48W in about 24 hours. Another high pressure center of 1021 mb located near 28N25W will remain nearly stationary. By Wednesday night, strong to near gale force winds are expected over the SW N Atlantic ahead of the next cold front forecast to enter the discussion area on Thursday. For additional information please visit http://www.hurricanes.gov/marine $$ GR