Atlantic Discussion

  • NHC Atlantic Tropical Weather Discussion
    by (nhcwebmaster) on June 24, 2018 at 5:14 PM

    000 AXNT20 KNHC 241714 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 114 PM EDT Sun Jun 24 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... The axis of a tropical wave is along 20W/21W from 04N to 18N, moving W at 10 kt. The wave shows up well in the TPW product. Scattered moderate convection associated to this wave is noted from 07N to 10N between 19W and 22W. The axis of a tropical wave is near 52W from 05N to 18N, moving W at 20 kt. A large area of African dust is noted behind the wave's axis based on the Saharan Air Layer (SAL) from CIMSS, and visible satellite imagery. Scattered moderate convection is noted where the wave meets the ITCZ from 06N to 08N between 50W and 55W. The axis of a tropical wave is over the eastern Caribbean along 63W, and extends from eastern Venezuela northward to the Leeward Islands, moving W at 20 kt. Scattered showers are near the wave's axis. A tropical wave extends from eastern Cuba to eastern Panama. This wave is interacting with an upper-level trough extending across the SE Bahamas to the central Caribbean. Scattered showers with embedded tstms are noted across the Old Bahama Channel, and near the northern coast of Cuba, mainly E of Villa Clara. Similar convection is also noted just ahead of the wave's axis over the Cayman islands. This wave will move across central Cuba early this evening, and across western Cuba tonight into Mon, and will continue to enhance convection over the island. Another tropical wave is near 90W, and extends over the Yucatan Peninsula and Guatemala into the eastern north Pacific region. This wave is currently generating scattered showers and tstms over Guatemala, and will continue to support convection over SE Mexico and the SW Gulf of Mexico today. ...MONSOON TROUGH/ITCZ... The monsoon trough extends off western Africa near 16N16W to 10N23W to 06N30W. The ITCZ continues from 06N30W to 05N45W to the coast of Guyana near 07N59W. Outside of the convection associated with the tropical waves, scattered moderate convection is noted within about 120 nm N of the ITCZ axis W of 35W. ...DISCUSSION... GULF OF MEXICO... An upper-level low is centered near 21N97W. A large area of showers and tstms is within about 270 nm NE semicircle of the low center, covering mainly the Gulf waters from 21N-26N between 93W- 97W. The low will drift westward into Mexico while weakening inland by Tue. This system will continue to enhance convection across the western Gulf, and likely across the states of Tamaulipas and Veracruz in Mexico on Mon, as well as over southern Texas. A 1019 mb high is over the eastern Gulf near 27N85W with a ridge extending westward toward the coast of Texas. The ridge will drift to over the northern Gulf waters through Tue, supporting moderate to fresh SE return flow over the northwestern Gulf. A trough moving west off the western coast of the Yucatan Peninsula each night will further enhance overnight winds over much of the southwestern Gulf waters. CARIBBEAN SEA... A series of tropical waves will move westward across the tropical north Atlantic and Caribbean Sea through the middle of next week. Currently, two tropical waves are propagating across the basin, one moving across the central Caribbean, and another tropical wave is moving across the eastern Caribbean. Please, see Tropical Waves section for more details. Expect increasing showers and isolated thunderstorms in association with the passage of these tropical waves. Fresh to strong winds are noted across the central and eastern Caribbean, as well as the Gulf of Honduras, with gentle to moderate winds prevailing elsewhere. Sea heights of near 11 ft are seen over the south-central Caribbean based on altimeter data. Winds are forecast to reach near gale force off Colombia at night. Little change is expected through the middle of the week. Areal coverage of fresh to strong trades will decrease afterwards as high pressure north of the area weakens. Seas are forecast to build to 11-13 ft over the south-central Caribbean by early Mon. Nocturnal winds will pulse to fresh to strong winds the next couple of nights in the Gulf of Honduras. ATLANTIC OCEAN... High pressure of 1029 mb centered near 31N52W extends a ridge westward across the forecast area. Fresh to strong trade are noted per scatterometer data E of the Lesser Antilles to about 50W. Altimeter data indicate sea heights of near 10 ft within this area of winds. This high pressure will remain nearly stationary through Tue while weakening. As result, the pressure gradient will loosen with diminishing winds and subsiding seas E of the Lesser Antilles by Tue. Nocturnal winds will continue to pulse to fresh to strong the next several nights off Hispaniola. For additional information please visit $$ GR […]