000 AXNT20 KNHC 170546 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 146 AM EDT Sun Jun 17 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 0000 UTC surface analysis and satellite imagery through 0530 UTC. ...TROPICAL WAVES... Three tropical waves are noted between the W coast of Africa and the Lesser Antilles. A tropical wave extends its axis along 20W between 04N-13N. This system is well defined in the TPW product and model diagnostics guidance. Scattered moderate convection is from 06N-11N between 18W-25W. A tropical wave is in the E Atlantic, with axis extending from 12N37W to 02N39W, moving W at 10-15 kt. A modest surge of moistened air is noted in association with the wave in TPW imagery. Scattered showers are noted along the wave axis and vicinity between 36W-42W. A tropical wave is in the central Atlantic, with axis extending from 15N50W to 05N51W, moving W at 10 kt. The wave coincides with a high amplitude bulge of moisture as depicted in the TPW product. Currently, shallow moisture and scattered showers are observed near the wave's axis from 08N-12N. A tropical wave is moving westward across the eastern Caribbean. Its axis extends along 68W. African dust surrounds the wave. As a result, shallow moisture with embedded showers are noted with this wave. A tropical wave is moving across the southern Yucatan Peninsula, with axis along 91W from 11N-19N, moving W at 10 kt. Scattered to numerous moderate convection prevails in the wave's environment affecting the area between 88W-93W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 10N14W to 08N31W. The ITCZ is analyzed from 04N41W to 05N50W, then resumes near 07N53W to 07N58W. Besides the convection mentioned in the Tropical Waves section, scattered showers are within 90 nm on either side of both boundaries between 35W-50W. ...DISCUSSION... GULF OF MEXICO... A surface trough extends across the western Gulf from 25N93W to 19N95W. Fresh to locally strong winds are near the trough axis prevailing mostly across the central Gulf waters between 88W-94W. Scattered moderate convection is noted between 86W-93W. This activity is supported by an upper-level low, currently centered near 15N95W. Scattered to numerous convection follows the trough covering the far NW Caribbean, the Yucatan Channel, and the Yucatan Peninsula. Although environmental conditions are not expected to be favorable for significant tropical cyclone development, heavy rains and gusty winds are likely to spread across the Gulf waters overnight, and will reach portions of the Texas and southwestern Louisiana coasts later today. The remainder of the Gulf is under the influence of a ridge. The surface trough will move WNW through Sun night accompanied by numerous showers and thunderstorms that could produce rough seas. A tightening of the pressure gradient between the trough and high pressure that extends westward from the Atlantic will continue to support fresh to strong SE winds over the west-central Gulf waters. These winds will spread westward through Tue while gradually diminishing with the trough shifting inland over Texas. CARIBBEAN SEA... As previously mentioned, an area of moderate convection covers the far west Caribbean, including the Yucatan Channel, mainly west of 82W. This convective activity is the result of a trough interacting with an upper-level low centered over the Gulf of Mexico. Strong trades across the central Caribbean between 69W and 83W will slowly diminish tonight. The strongest winds will become confined to the S central waters, with similar pulsing winds continuing in the vicinity of the Gulf of Honduras. Two tropical waves are noted across the basin. Please, see the Tropical Wave section for details. A tropical wave is forecast to reach the waters E of the Lesser Antilles Sun night through Mon night, and the eastern Caribbean Tue through Wed night. It is expected to be accompanied by scattered showers and thunderstorms. As the wave moves across the Lesser Antilles into the eastern Caribbean, the moisture field is forecast by the GFS computer model to expand over the Leeward Islands, the UK/US Virgin Islands and Puerto Rico, bringing an increase in showers and tstms with likely gusty winds by mid week. ATLANTIC OCEAN... A cold front enters the forecast waters and extends from 31N64W to 29N70W to 31N78W. Scattered moderate convection is noted along and south of the front between 58W-68W. A surface trough remains near the northern Bahamas from 29N76W to 26N77W with no convection. High pressure of 1032 mb located just over the Azores extends a ridge across the forecast area. Three tropical waves are moving westward across the southern periphery of the ridge. The trough offshore northern Bahamas will be overtaken by the cold front towards the morning hours. The cold front will continue moving southeast through early next week. The high pressure ridge south of the boundaries will shift southward across the western Atlantic. For additional information please visit http://www.hurricanes.gov/marine $$ ERA