000 AXNT20 KNHC 291719 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 119 PM EDT Mon May 29 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 1700 UTC. ...TROPICAL WAVES... A tropical wave is located over the eastern Atlc off the coast of W Africa. The axis of the wave extends from 16N20W to 05N22W. The wave is moving W at 20 kt. TPW satellite imagery shows the wave is embedded in moderately moist environment near the ITCZ. This wave possesses a good signature in the 700 mb wind flow field. There is no significant convection currently associated with this wave. A tropical wave located over the eastern Atlc has an axis extending from 11N34W to 02N36W. The wave is moving W at 10 to 15 kt. TPW satellite imagery shows the wave is embedded in a moderately moist environment near the ITCZ. The wave lies just to the SE of large area of dry air associated with the Saharan Air Layer to the N of 10N. This wave possesses a weak signature in the 700 mb wind flow field. Scattered moderate convection is seen from 08N to 10N between 29W and 32W. A tropical wave over the western Atlc and Suriname has an axis extending from 12N56W to 03N55W. The wave is moving W at 15 to 20 kt. TPW satellite imagery shows the wave is embedded a moderately moist environment. Dry air associated with the Saharan Air Layer N of 10N is impinging on the wave from the NE. This wave possesses a weak signature in the 700 mb wind flow field. Scattered moderate and isolated strong convection is seen from 06N to 10N between 54W and 59W. A tropical wave over the eastern Caribbean and Venezuela has an axis extending from 15N66W to 02N67W. The wave is moving W at 15 to 20 kt. TPW satellite imagery shows the wave is embedded in a moderately moist environment. This wave possesses a good signature in the 700 mb wind flow field. Scattered moderate and isolated strong convection is sheared NE of the wave from 19N to 22N between 61W and 66W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends SW into the tropical Atlc from the coast of Senegal in West Africa near 12N16W to 09N18W. The ITCZ continues near 07N24W to 06N33W...then resumes W of a tropical wave near 05N37W and continues to the coast of South America near 02N49W. Scattered moderate and isolated moderate convection is found within 90 nm either side of a line from 03N40W to 07N54W. ...DISCUSSION... GULF OF MEXICO... A frontal boundary stalling along the Rio Grande and SE Texas has served as the primary focus for the development of showers and thunderstorms this morning. A squall line moved SE into the NW Gulf from Deep South Texas earlier this morning, but it has begun to weaken. Satellite imagery and lightning detection data show more showers and thunderstorms are pushing eastward S of Louisiana in the vicinity of 26N. Elsewhere, a 1018 mb high is centered over the NE Gulf near 27N85W. 5-10 kt anticyclonic winds revolve around the high over the NE Gulf. N of 23N and W of 90W 10-20 kt SE surface winds are over the W Gulf. Scattered showers and isolated thunderstorms occurring over the Bay of Campeche and S Mexico S of 23N. In the upper levels, a ridge is over the eastern Gulf adjacent to Florida. A sharp mid to upper-level trough is pushing eastward toward the NW Gulf from Northern Mexico. Abundant deep layer moisture is pooling to the east of the upper-level trough over most of the Gulf, except over S Florida and the SE Gulf where subsidence associated with the ridge is noted. Expect convection to persist over the NW Gulf as the stalled frontal boundary remains inland just to the NW. Also expect showers to persist over the Bay of Campeche during the next 24 hours as upper-level divergence associated with the upper-level trough serves as a catalyst for deep convection. CARIBBEAN SEA... A tropical wave is passing over the E Caribbean. See the tropical waves section for more details. The monsoon trough extends over Costa Rica, Panama and Northern Colombia. Scattered moderate and isolated strong convection associated with the trough is taking place over the SW Caribbean S of 11N. A broad upper-level ridge extends N over the Caribbean from Central and South America. An upper level trough passes just N of the Caribbean from the Bahamas to just n of Puerto Rico. Subsident flow between the ridge and trough will generally inhibit convection, except for in the vicinity of the tropical wave, which will produce some showers and thunderstorms over the the next 24 hours as it moves from the Eastern Caribbean into the Central Caribbean. Also expect continuing convection over the SW Caribbean, and Central America. HISPANIOLA... Water vapor imagery shows strong subsidence over the Island, hindering convection. However, patches of low level moisture, embedded in the trade wind flow, will maintain isolated showers today. The approaching tropical wave will bring increasing shower coverage to Hispaniola by Tuesday. ATLANTIC OCEAN... A large 1027 mb high is centered over the central Atlc near 33N29W. Light showers are over the Canary Islands. Three tropical waves are over the tropical Atlantic. Please refer to the Tropical Waves section for more details. Saharan dry air and dust is noted across much of the Atlantic Ocean N of 10N and E of 50W. Of note in the upper levels, an elongated upper-level trough that curves from N of Puerto Rico toward the Central Atlc is producing upper- level divergence over Puerto Rico and the Virgin Islands. The trough is influence a tropical wave that is currently passing S of Puerto Rico. Expect during the next 24 hours for more showers to form in this favorable environment over the Atlc in the vicinity of the Leeward and Windward Islands. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy