000 AXNT20 KNHC 011032 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 632 AM EDT Sun Jul 1 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...TROPICAL WAVES... The tropical wave that most recently emerged off the west coast of Africa has an axis extending from 03N20W to 15N20W and is heading W around 20 kt. Scattered to numerous moderate and isolated strong convection is noted on either side of the wave axis from 05N to 12N eastward from 24W to beyond the coast of Africa. A moisture surge in the TPW product coincides with this wave. A tropical wave has an axis extending from 03N39W to 17N39W. This wave is quickly moving W around 30 kt. This wave is well defined in model diagnostics as well as TPW satellite imagery. Scattered moderate convection is present within 90 nm of where the wave meets the ITCZ near 06N. This wave is surrounded by dry Saharan air which is inhibiting deep convection. A tropical wave has an axis extending from 04N56W to 19N55W, moving westward around 15 knots. Scattered moderate convection is seen where the wave meets the ITCZ from 06N to 08N between 53W and 58W. The wave shows up well in model diagnostics guidance and the TPW product. African dust surrounds this wave also. Tropical moisture associated with this feature will reach the Windward Islands by this afternoon and produce a modest increase in the likelihood of showers and isolated tstms for the eastern Caribbean. A tropical wave has an axis extending N from northeast Colombia near 08N76W to just SW of the eastern tip of Cuba. This wave is moving W between 10 and 15 kt and has dry Saharan dust in its environment. As a result, there is no significant convection currently associated with it. The wave will reach Central America by Sun night. Another tropical wave has an axis extending N from 11N94W over the Isthmus of Tehuantepec into the Bay of Campeche near 20N92W. This wave is slowing down and moving W around 10 kt. TPW satellite imagery and model diagnostics show this wave to be poorly defined. No significant convection is currently associated with this wave. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean from the coast of Mauritania near 17N16W to 17N17W, then resumes near 09N22W to 06N36W. The ITCZ stretches from 06N42W to 07N48W to 06N54W. Aside from the convection associated with the tropical waves, scattered moderate convection is observed from 05N to 07N between 24W and 29W and from 06N to 08N between 47W and 53W. ...DISCUSSION... GULF OF MEXICO... A surface trough extends over the northeastern Gulf from a 1014 mb low over the Florida Panhandle near 31N85W to 28N86W. Abundant cloudiness and scattered showers are associated with the low/trough affecting mainly the waters N of 28N and E of 87W. The low and trough will move little tonight, then they will drift northwestward through the day while weakening. Scattered showers and thunderstorms will continue over much of the NE/north-central Gulf waters through at least Mon. The remainder of the basin is under the influence of a weak high pressure center of 1016 mb located over the north-central Gulf near 27N90W. This system is producing light to gentle anticyclonic flow and seas of 2-3 ft over the eastern half of the Gulf, and gentle to moderate Se to S 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. This weak high pressure will change little through mid-week. A surface trough will emerge off the Yucatan Peninsula each evening through Wed, enhancing nocturnal winds over the SW Gulf through this period. CARIBBEAN SEA... A tropical wave is moving across the central Caribbean. Please, see the Tropical Waves section for details. Recent scatterometer data depicted fresh to strong winds across the south-central Caribbean south of 14N between 72W-78W, while moderate to fresh trades prevail across the remainder of the basin S of 18N and E of 80W. Light to gentle winds are noted over the NW Caribbean. A surface ridge will remain north and northeast of the Caribbean and Tropical N Atlantic waters through the next few days. Fresh to strong winds across the south-central Caribbean will gradually diminish through Tue before strengthening again on Wed. Convection continues to flare up over the SW Caribbean mainly in the vicinity of the monsoon trough, which is along Central America at this time. The upper-level low, currently over Cuba, will drift westward into the NW Caribbean over the weekend, and will continue to enhance convection across the basin. ATLANTIC OCEAN... Three 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 32N48W to 29N51W. Light winds are on either side of the trough axis based on scatterometer data. This trough is a surface reflection of an upper-level low spinning near 30N50W. Scattered showers are associated with this trough. A 1033 mb surface high located NW of the Azores near 45N36W is in control of the remainder of the forecast area, extending a ridge SW across the west-central Atlantic. Moderate to fresh winds are around the southern periphery of the ridge W of 50W to the Lesser Antilles. The ridge will weaken through Tue in response to the development of broad low pressure system NE of the Bahamas. A surface trough will develop from the low pressure and move westward across the NW Bahamas Tue, and inland Florida Wed. Scattered showers and thunderstorms are expected with the trough. Otherwise, generally tranquil marine conditions are expected across the region through the middle of next week. GOES-16 RGB Geocolor showed an extensive area of African dust that extends from the west coast of Africa to the eastern Caribbean this afternoon. The Saharan dust occasionally obscures sky conditions near the Caribbean islands. The dust turns skies hazy, reducing visibility and can result in poor air quality. For additional information please visit http://www.hurricanes.gov/marine $$ CAM/ASL