000 AXNT20 KNHC 021034 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 634 AM EDT Tue Jul 02 2019 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 1015 UTC. ...TROPICAL WAVES... A far eastern Atlantic tropical wave with axis along 21W from 05N to 22N is moving westward at 10-15 kt. Satellite imagery indicates a possible mid-level circulation near 14N21W. Scattered showers and thunderstorms are seen within 180 nm either side of the wave axis from 05N to 10N. An eastern Atlantic tropical wave with axis along 40W from 02N to 17N is moving westward at estimated speed of 20-25 kt. A trade wind surge trails the wave. Model diagnostics depict this wave. The total precipitable water (TPW) imagery shows a maximum in moisture content across the wave axis from 04N to 11N and between 35W-42W. Scattered showers and isolated thunderstorms are noted from 06N to 10N between 38W and 42W. This wave is forecast to impact the eastern Caribbean Sea Thu through Fri. A central Caribbean Sea tropical wave with axis along 71W south of 16N is moving westward at about 20 kt. Latest TPW imagery shows moisture concentrated to the south of 15N and between 70W and 77W. The wave is moving through an area of broken to overcast multilayered clouds and upper-level strong southwest winds that are in advance of an upper-level trough and low over the western Caribbean. Isolated showers and thunderstorms are south 14N between 67W and 71W. A western Caribbean tropical wave with axis roughly along 81W is moving westward at about 17 kt. This wave is passing underneath an area of subsidence and dry air present north of 13N in association with a western Caribbean upper-level trough and low. The only moisture content with this wave is found in the usual far southwestern Caribbean area primarily south of 13N between 76W and 81W, where isolated showers and thunderstorms are occurring. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coastal of southwestern Senegal near its border with Guinea-Bissau at 12N17W and continues to 10N23W, where latest scatterometer data indicates that it transitions to the ITCZ and continues to 08N31W and to 06N38W. It resumes to the west of the tropical wave along 40W at 06N41W and to 04N51W. Aside from shower and thunderstorm activity associated with tropical waves as described above, only scattered moderate convection is within 150 nm south of the ITCZ between 31W-37W. GULF OF MEXICO... An upper-level low over central Mexico is embedded within a broad trough that stretches from Missouri to Texas and to the central region of Mexico. Strong upper-level southerly winds to the east of the trough and low expand eastward to the western Gulf. These winds are spreading upper-level moisture in the form of mostly broken high clouds across the western and north-central Gulf areas. The total precipitable water imagery depicts abundant moisture over the much of the western and central Gulf, and is spreading northward. Scattered showers and isolated thunderstorms are noted west of 91W, and also north of 25N between 85W and 91W. The majority of the activity over the SW Gulf and Bay of Campeche moved offshore from the southeast section of Mexico, and is being steered northward by the strong upper-level southerly flow. Isolated showers and thunderstorms over the far eastern Bay of Campeche and along the coast of the Yucatan Peninsula are also tied to the nocturnal Yucatan Peninsula trough. With this moisture in place and along with atmospheric conditions becoming more unstable today, expect for the shower and thunderstorm activity to further increase through tonight and into Wed over the western and north-central Gulf waters. Some of this activity may be accompanied by strong gusty winds and rough seas. Isolated showers and thunderstorms are expected elsewhere over the Gulf through Wed. The upper level-low over central Mexico is forecast to lift northeastward toward central Texas tonight and Wed while shearing out in a northeast to southwest fashion. A weak 1018 mb high center is analyzed over the extreme southern part of the eastern Gulf near 25N85W, with associated anticyclonic flow, as depicted in the latest Ascat pass, covering much of the Gulf. The weak high pressure will change little through the upcoming weekend. As referenced above in relation to isolated showers and thunderstorms over the far eastern Bay of Campeche, the same culprit trough will develop over the Yucatan Peninsula each afternoon and move offshore across the Bay of Campeche during the evening hours, bringing fresh to locally strong northeast to east winds to the SW Gulf of Mexico. CARIBBEAN SEA... An upper-level trough extends from the central Atlantic near 28N44W southwestward to the Mona Passage and eastern Dominican Republic, and from there it continues southwestward to a rather ill-defined upper-level low at 16N78W and to a base at 10N81W. Strong upper-level southwest to west winds are southeast of the trough. These winds are advecting abundant upper-level moisture in the form of broken high clouds east-northeastward to across the south-central and eastern Caribbean. Isolated showers and thunderstorms are south of 13N and between 67W and 65W. Dry sinking air is situated to the northwest of the upper- level trough to near 82W, where skies are relatively cloud free except for small pockets of scattered low clouds. Scattered moderate to isolated strong convection over northwestern Colombia is being aided by the eastern extension of the E Pacific monsoon trough. This activity is moving westward and has recently crossed to over the southern part of Panama and to just inland the Pacific coast of Colombia. The pressure gradient, between N Atlantic high pressure and lower pressures in northern Colombia, will support strong to near gale- force winds, pulsing each night off the coast of Colombia and near the Gulf of Venezuela through Sat. High pressure will build north of the region Fri through Sat night, with the associated pressure gradient to bring strong east winds and building seas across much of the central Caribbean. Moderate to fresh trade winds will prevail elsewhere over the Caribbean waters. A tropical wave, currently over eastern Atlantic as described above, is expected to move across the Windward Islands and far eastern Caribbean on Thu and across the rest of the eastern Caribbean on Fri. It will be accompanied by scattered showers and thunderstorms. Strong gusty winds can be expected with this activity. ATLANTIC OCEAN... A cold front dipping southward extends from 32N61W to 30N68W and northwestward to north of the area at 32N75W. A surface rough out ahead of it extends from near 30N66W to 25N73W. These features are being driven by a broad deep-layer trough that is gradually sliding eastward north of 26N and between 54W and 71W. Scattered showers and isolated thunderstorms are seen within 90 nm either side of a line from 32N59W to 28N63W to 25N68W. Increasing scattered showers and thunderstorms are within 120 nm either side of a line from 32N57W to 29N61W and within 75 nm either side of a line from 29N61W to 25N68W. The deep-layer trough will shift eastward through the next 24 to 48 hours, while the cold front will reach from near 32N59W to 28N68W by early this evening and become stationary and dissipate by early Wed evening. Fresh to locally strong southwest winds will precede the cold front today. Isolated showers and thunderstorms are present from 25N to 27N between 70W and 75W and also south of 29N W of 75W. Elsewhere, broad scale high pressure is the main feature. It is forecast to change little through the next 48 hours. The associated gradient between it and relatively lower pressure to the south, over the Caribbean Sea, will allow for east winds to pulse to fresh to locally strong speeds between the southeastern Bahamas and Hispaniola in the late afternoons and evenings through the upcoming weekend. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre