000 AXNT20 KNHC 291707 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 107 PM EDT Fri Jun 29 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 extends from the Cabo Verde Islands near 16N23W to 04N23W moving W at 20 kt. This wave is noted in model diagnostics guidance and TPW animation. Convection is limited near the wave's axis. A tropical wave extends from 18N43W to 04N45W, moving westward 15 to 20 knots. Scattered moderate convection is near the southern end of the wave's axis. The wave shows up well in model diagnostics guidance and TPW product. Tropical moisture associated with this wave will reach the waters E of the Windward Islands tonight, and move across these islands on Sat, increasing the likelihood of showers and isolated tstms. The wave will enter the eastern Caribbean early on Sun. A tropical wave is moving across the eastern Caribbean and extends from the Virgin Islands to central Venezuela. Scattered moderate convection is noted just ahead the wave's axis from 12N- 16N between 66W-69W. A high amplitude N bulge of moisture is associated with this wave based on the TPW product. However, the GFS computer model indicates that most of the moisture field related to this wave will remain S of the Greater Antilles during the upcoming weekend, with only a slightly increase in tropical moisture across islands. This wave will move across the Caribbean basin through Sat night. Another tropical wave extends across the NW Caribbean and Central America into the EPAC region. Its axis is along 86W. Scattered moderate convection is where the wave meets the monsoon trough in the EPAC region. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean through the coast of Guinea near 10.5N14W and continues to 06N30W. The ITCZ begins near 06N30W and continues to 05N40W to the coast of South America near 05N52W. Aside from the convection related to the tropical waves, scattered moderate convection is from 04N-07N between 25W- 31W. ...DISCUSSION... GULF OF MEXICO... A surface trough extends across northern Florida into the NE Gulf. Scattered showers and tstms have flared up near the trough's axis, affecting roughly the waters NE of line from Tampa Bay to SE Louisiana. Doppler Radar from the SE U.S. also indicates scattered showers and tstms over the west coast of Florida and regional waters. This convective activity could produce locally gusty winds, briefly choppy seas and dangerous lightning. The remainder of the Gulf is under the influence of a weak high pressure center of 1019 mb located over the eastern Gulf near 25N88W. This system is producing light to gentle winds and seas of 2-3 ft over the eastern half of the Gulf, and gentle to moderate winds and seas of 3-5 ft over the western half of the Gulf. Moderate to fresh return flow is expected over the west- central and NW Gulf through the weekend. The Western Atlantic high pressure is forecast to weaken on Sat and remain stretched across Florida and the eastern Gulf. A surface trough will emerge off the Yucatan Peninsula each night, enhancing nocturnal winds in the SW Gulf through Tue. CARIBBEAN SEA... A pair of tropical waves are moving across the basin. Please, see Tropical Waves section for details. Recent scatterometer data provide observations of fresh to strong winds across the south- central Caribbean, and moderate to fresh trades across the remainder of the basin S of 18N E of 80W. Mainly gentle winds are noted over the NW Caribbean. Winds and seas in the central Caribbean will gradually diminish Sun through Tue as high pressure N of area weakens. Scattered moderate convection is seen over the SW Caribbean, mainly S of 11N between 77W-83W. Similar convection is over the eastern Caribbean due to the presence of a tropical wave. Isolated to scattered showers and tstms are over parts of Hispaniola, the Windward Passage, Jamaica and the Cayman Islands. An upper-level low centered over the Windward Passage is helping to induce this convective activity. The upper-level low will drift westward into the NW Caribbean over the weekend, and will continue to enhance convection across the area. ATLANTIC OCEAN... Two tropical waves are moving across the waters between the coast of West Africa and the Lesser Antilles. Refer to the Tropical Wave section above for details. A surface trough is over the central Atlantic and extends from 32N47W to 27N49W. Light winds are on either side of the trough's axis based on scatterometer data. This trough is a surface reflection of an-upper-level low spinning near 32N51W. Farther east, a cold front enters the forecast area near 31N12W and crosses just N of the Canary Islands to near 28.5N20W. A frontal trough continues from this point to 29N26W. High pressure of 1036 mb located NW of the Azores near 43N42W is in control of the remainder of the area, extending a ridge SW across the west-central Atlantic. Moderate to fresh winds are around the southern periphery of the ridge W of 48W to the Lesser Antilles. The ridge will slowly weaken Sun through Tue. Generally benign marine conditions are expected across the region through early next week. For additional information please visit http://www.hurricanes.gov/marine $$ GR