000 AXNT20 KNHC 151726 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 126 PM EDT Fri Jun 15 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. ...TROPICAL WAVES... A tropical wave is in the E Atlantic, with axis extending from 13N29W to 03N30W, moving W at 10 kt. The wave shows up well as a low amplitude moisture surge on the TPW product. The GOES-16 Geocolor RGB imagery shows the presence of the Saharan dust and dry air N of the wave at 15N. Isolated moderate convection is noted where the wave meets the ITCZ. A tropical wave is in the central Atlantic, with axis extending from 14N46W to 03N47W, moving W at 10-15 kt. The wave is well depicted in the TPW product. Shallow moisture and isolated showers are near the wave's axis. A tropical wave is moving westward across the eastern Caribbean. Its axis extends 61W/62W. African dust also surrounds the wave. As a result, shallow moisture with embedded showers is associated with the wave. Moisture related to this system will reach Puerto Rico late today into tonight, and Hispaniola early on Sun, increasing the likelihood of showers and isolated tstms. A tropical wave is over the W Caribbean, with axis along 82W from 10N-19N, moving W at 10-15 kt. Scattered showers and tstms are seen over the SW Caribbean, likely a combination of the wave and the proximity of the Monsoon Through. The wave will move westward into Central America through Sat, helping to induce some shower and tstm activity. The GFS model indicates plenty of moisture over Central America this upcoming weekend. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 11N15W to 06N25W. The ITCZ continues from 06N25W to 07N40W to 06N50W to the coast of Guyana near 07N59W. Besides the convection mentioned in the Tropical Waves section, scattered moderate convection is noted within about 75 nm S of the monsoon trough between 14W-22W. Similar convection is also seen from 07N-09N between 37W- 40W. ...DISCUSSION... GULF OF MEXICO... A surface trough is analyzed over the SW Gulf and extends from 23N95W to the central Bay of Campeche near 19N93W. Scattered showers and isolated thunderstorms are noted over the western Gulf under a SE wind flow. An upper-level low centered over the western Gulf is helping to induce this convective activity. A large area of cloudiness with embedded showers and tstms is affecting the far SE Gulf, including parts of the Yucatan Peninsula and the Yucatan Channel. This large area of moisture is associated with a second and stronger trough, that will be added to the 1800 UTC surface analysis. A ridge dominates the remainder of the Gulf waters. The surface trough across the Bay of Campeche and western Gulf will shift WNW moving inland of Mexico by this evening. The second and stronger trough will shift from the NW Caribbean through NW Gulf tonight through Sun, accompanied by widespread convection. A tightening pressure gradient E of this second trough will induce fresh SE winds in west-central Gulf waters tonight, becoming strong to near gale in the central Gulf this weekend, spreading W through early next week. CARIBBEAN SEA... A large area of disorganized showers and thunderstorms over the northwestern Caribbean Sea and the Yucatan Peninsula is associated with a surface trough. While significant development of this system is not anticipated, heavy rain and strong gusty winds are occurring across the Yucatan Peninsula today, and will overspread the central Gulf of Mexico on Saturday and reach portions of the Texas and southwestern Louisiana coasts by Sunday. A diffluent pattern aloft is currently helping to induce this convective activity. Scattered showers and tstms are also seen over the SW Caribbean just N of Panama. Two tropical waves are moving westward across the basin. Please, see Tropical Wave section for details. Recent scatterometer data provided observations of fresh to strong winds across the central Caribbean, with seas of 10-11 ft. The aerial extent of the strong trades, roughly between 70W and 83W, will slightly diminish this weekend. However, fresh to strong winds will persist across the Gulf of Honduras and the NW Caribbean over the next couple of days in association with the surface trough. ATLANTIC OCEAN... As of 1500 UTC, a surface trough is located E of Florida, and extends from 31N77W to 27N80W. Scattered showers and tstms are near and ahead of the trough. Farther E, a stationary front enters the forecast region near 31N54W and extends SW to near 27N60W. An upper-level low is generating some showers and isolated tstms just E of the frontal boundary. The remainder of the Atlantic Ocean is under the influence of a ridge, anchored by a 1030 mb high pressure located SW of the Azores near 36N32W. The trough offshore of northern and central Florida will be overtaken by a backdoor cold front this weekend, which will move S through early next week. The high pressure ridge located S of these boundaries will sink southward ahead of the features. New high pres is forecast to build from N of the area by Tue. For additional information please visit http://www.hurricanes.gov/marine $$ GR