000 AXNT20 KNHC 131804 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 204 PM EDT Wed Jun 13 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 1745 UTC. ...TROPICAL WAVES... A tropical wave is in the E Atlc with axis extending from 11N21W to 02N23W, moving W at 10-15 kt. The wave is in a favorable wind shear environment, and the CIRA LPW show moderate moisture associated with it. However, the GOES-16 Geocolor RGB imagery show the presence of the Saharan Air Layer in that region, which seem to be hindering the development of deep convection at the time. A tropical wave is in the central Atlc with axis extending from 10N39W to 01N39W, moving W at 15 kt. GOES SAL and Dust RGBs show the wave is under the influence of dry air and dust, which is hindering the development of deep convection. However, upper level diffluent flow and shallow moisture in the vicinity of the ITCZ support isolated to scattered showers from 03N to 10N between 37W and 44W. A tropical wave is about 390 nm SE of the Windward Islands with axis extending from 14N54W to 03N55W, moving W at 5-10 kt. The wave is ahead of the Saharan Air Layer, however CIRA LPW imagery show some dry air intrusion to the wave environment already. This factor along with strong wind shear in the region is hindering the development of deep convection at the time. Isolated showers are from 06N-11N between 50W and 63W. A tropical wave is in the central Caribbean with axis extending from 20N73W to 10N75W, moving west at 20 kt. Meteosat Split Window imagery show SAL dry air moving across the central and E Caribbean, which along with strong wind shear hinder the development of deep convection at the time. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 09N13W to 07N22W. The ITCZ extends from 07N24W to 05N38W, then resumes west of a tropical wave near 04N41W and continues to 04N51W. Besides the convection mentioned in the tropical waves section, scattered moderate convection is from 05N-08N between 12W-18W, and from 02N-09N between 30W-50W. ...DISCUSSION... GULF OF MEXICO... The subtropical Atlc ridge continue to extend to great portions of the northern and eastern Gulf while low pressure dominate the SW Gulf waters. Low level moisture advecting from the Caribbean along with a middle level low in the W Gulf support scattered showers in the bay of Campeche. Farther east, a surface trough along the E Yucatan Peninsula and Belize is generating disorganized showers and thunderstorms over the northwestern Caribbean Sea, extending into the Yucatan Channel. This later area of disturbed weather is forecast to move west-northwestward and move into the southwestern Gulf by Thursday afternoon. No development is expected for the next day or so due to land interaction with the Yucatan Peninsula and strong upper-level winds. However, environmental conditions could become slightly more conducive for some development of this disturbance while it moves across the southwestern Gulf of Mexico on Friday and Saturday. CARIBBEAN SEA... Disorganized showers and thunderstorms over the northwestern Caribbean Sea are associated with a surface trough. This area of disturbed weather, accompanied by strong gusty winds, is forecast to move west-northwestward over Belize and the Yucatan Peninsula today, and move into the southwestern Gulf of Mexico by Thursday afternoon. Farther east, a tropical wave moves across the central Caribbean waters, however both Saharan dry air and strong wind shear in the region hinder deep convection development at the time. Otherwise, scattered moderate to isolated strong convection is within 90 nm off the coasts of Panama and Nicaragua. ATLANTIC OCEAN... Southeasterly flow continue to advect moisture to the SW N Atlc where an upper level low and diffluent flow in the middle levels support scattered heavy showers in the vicinity of a surface trough that extends from 30N79W across SE Florida to the straits of Florida. Farther east, an upper level trough in the NW Atlc continue to support a frontal system that extends as a cold front from 31N56W to 27N64W. A surface trough is ahead of the cold front tail along 31N54W to 27N60W supporting scattered heavy showers N of 26N between 53W and 64W. Otherwise, the subtropical Atlc ridge dominates the remainder basin. The ridge is forecast to shift east Fri and Sat allowing a weak cold front to move east through the waters north of 26N over the weekend. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos