000 AXNT20 KNHC 031034 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 634 AM EDT Wed Jul 3 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 27W/28W from 04N-20N is moving westward at 10-15 kt. Satellite imagery shows an apparent northern mid-level vorticity on the wave near 14N26W. The latest TPW imagery animation continues to depict increasing moisture east of the wave's axis in an inverted-V shape. However since the wave is moving through stable environment, the observed moisture is rather capped allowing for only isolated showers and thunderstorms within 150 nm either side of the wave axis from 06N- 09N. A central Atlantic tropical wave with axis along 48W from 03N- 19N has become better defined in its satellite signature during the overnight hours. It is moving westward near 20 kt. Model diagnostics depict this wave very well. The TPW satellite animation shows a very deep moisture area, also in an inverted-V shape, behind this wave from 04N-16N and between 40W-53W. Deep convection consisting of the scattered moderate to isolated intensity is increasing behind the wave from 06N-10N and between 41W-45W. In addition, a trade wind surge trails this wave. This wave is forecast to impact the eastern Caribbean by Thu through Fri, bringing enhanced showers and thunderstorms with gusty winds. The previous analyzed western Caribbean tropical wave with axis along 80W is presently not identifiable. as it has lost its signature. The earlier tropical wave that was analyzed over Central America has advance into the eastern Pacific along 85W. Its northern portion extends inland to northern Costa Rica and central Nicaragua. Scattered showers and thunderstorms have increased during the overnight hours over the central portion of Nicaragua, and are moving westward. Isolated showers and thunderstorms are along the coast of central and southern Nicaragua. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from coast of border between Mauritania and Senegal near 16N16W and continues south- southwestward to 08N26W. Latest scatterometer data indicates that it transitions to the ITCZ west of the tropical along 28W and continues to 05N47W. Aside from shower and thunderstorm activity associated with tropical waves as described above, scattered moderate convection that moved offshore Africa in advance of the next tropical wave is seen within 270 nm south of the monsoon trough between 16W-21W. Scattered moderate convection is within 60 nm either side of the ITCZ between 36W-41W. GULF OF MEXICO... An upper-level elongated trough extends from northern Texas to an upper-level low over north-central Mexico. Associated upper- level strong southwest winds cover far western Gulf. These winds continue to advect abundant moisture northward over the western Gulf. The earlier observed scattered moderate convection over the northwest Gulf weakened and diminished in coverage during the evening and overnight hours. Scattered showers and isolated thunderstorms are seen north of 26N between 87W-94W. Isolated showers and thunderstorms are elsewhere west of 90W. Expect for scattered showers and thunderstorms to develop again today over much of the western and north-central Gulf as deep moisture remains in place. This activity is expected to decrease some tonight and Thu as the aforementioned upper-level trough shear out and weakens. A weak 1015 mb high center is over the eastern Gulf at 25N86W. Weak high pressure is over the area, and is generally expected to change little through the upcoming weekend, resulting in mainly gentle to moderate winds across the Gulf, with the exception of the far western Gulf where southeast to south winds are mainly in the fresh range. These winds will diminish beginning on Fri. A trough will develop over the Yucatan Peninsula each day and move across the Bay of Campeche during the evening, bringing fresh to locally strong winds to the SW Gulf through Thu night. CARIBBEAN SEA... An upper-level trough extends from well northeast of the Caribbean to across the northeastern Caribbean, then to a weak upper-level low moving westward at 17N72W, and from there it stretches southwestward and westward as a shear axis to across northern Nicaragua. 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 the south-central and eastern Caribbean. Isolated showers and thunderstorms are south of 12N and between 77W-83W. 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. This section of the Caribbean remains under the SE periphery of mid to upper-level ridging present over the central Gulf of Mexico. The gradient between high pressure over the central Atlantic and low pressure in Colombia will support strong to near gale force winds each night off the coast of Colombia and Gulf of Venezuela through Sat. Moderate to fresh trades will continue elsewhere across the Caribbean the next several days. A tropical wave is forecast to impact the eastern Caribbean by Thu through Fri, likely reaching the central Caribbean from Fri night into Sat. It will be accompanied by scattered showers and thunderstorms. Strong gusty winds can be expected with this activity. ATLANTIC OCEAN... A cold front was analyzed at 06Z along a position from near 32N54W to 29N60W, where it transitions to a dissipating stationary front to 28N66W and to 29N70W. A rather sharp upper trough/shear axis is over this cold front. A pre-frontal trough extends from near 29N59W to 26N68W. Scattered moderate convection, mainly as a result from the upper trough dynamics, are moving east-northeast within 30 nm of a line from 32N56W to 30N59W. Isolated showers and isolated thunderstorms are within 30 nm of the stationary front and also within 30 nm of the trough between 62W-68W. Farther south, a surface to low-level trough is approaching the Leeward Islands along a position from near 20N59W to 16N60W. Isolated showers are within 60 nm either side of the trough. Elsewhere, a 1028 mb high pressure center located well north of the area at 35N34W has an associated ridge stretching southwestward to 32N42W to 27N52W, then narrows as it reaches to near 23N60W. An overnight Ascat pass nicely captured the anticyclone flow associated with this ridge. A weak 1015 mb high is centered at 28N74W. High pressure covers the Atlantic basin outside the tropical waves. The cold front and stationary front is forecast to dissipate by early this evening. High pressure will build over northern waters Thu through Sat night, which will support pulsing fresh to strong winds north of Hispaniola each evening through Sat. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre