000 AXNT20 KNHC 251011 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 611 AM EDT Wed Oct 25 2017 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 1000 UTC. ...TROPICAL WAVES... A tropical wave is E of the Lesser Antilles with axis extending from 19N56W to 07N58W. Interaction of the wave with an elongated upper level trough across the E Caribbean with base extending into S America is maintaining the wave nearly stationary. Satellite derived data show the wave is in a region of strong vertical wind shear. However, abundant low to middle level moisture and upper level diffluence between the trough and a broad ridge over the central Atlc support scattered moderate convection and isolated tstms from 07N-19N between 50W-61W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 11N16W to 10N19W. The Intertropical Convergence Zone axis extends from 10N19W to 08N30W to 05N45W to 05N52W. Aside from the convection associated with the tropical wave, scattered moderate to strong convection and isolated tstms are from 02N-16N between 27W-50W and from 06N-10N E of 16W. ...DISCUSSION... GULF OF MEXICO... A vigorous middle to upper level trough is over the Great Lakes and Mississippi River valley with a broad base dipping southward to near 26N over the northern Gulf. The deep layered trough supports a cold front extending from south Florida near 25N81W SW to the Yucatan peninsula near 21N86W to central Guatemala. Scattered showers and isolated tstms are occurring within 90 nm E of the front while isolated showers are within 75 nm W of the boundary. Fresh to strong northerly winds associated with the passage of the front are over the entire basin, which are expected to gradually decrease in areal coverage and be confined to the Bay of Campeche by tonight. Otherwise, surface high pressure continues to build across the Gulf today into Thursday. CARIBBEAN SEA... A broad upper level ridge over the western Caribbean continues to provide an overall divergent environment aloft. Underneath this divergent flow, a 1006 mb low is centered off the coast of Nicaragua near 13N82W, which is also connected to the EPAC monsoon trough that then extends SE to inland NW Colombia. Numerous heavy showers and scattered tstms associated with this system are over Nicaragua while scattered heavy showers and tstms extend ESE covering the region S of 16N between 74W-84W. Over the far NW Caribbean, a surface pre-frontal trough along 21N82W to 15N87W support scattered showers and tstms in the Gulf of Honduras and elsewhere W of 80W. A surface trough extends from 21N60W to the NE Caribbean near 15N64W and is generating isolated showers and tstms over the Leeward and Virgin Islands. Showers are expected to extend to Puerto Rico later this morning. A deep layered trough covers the remainder basin with water vapor imagery showing strong subsidence, which is supporting fair weather. In the far SE Caribbean, proximity of a tropical wave with axis near 57W support scattered to isolated showers across the Windward Islands. A cold front currently moving across the Straits of Florida will move into the NW Caribbean today increasing northerly winds into fresh to strong levels through Thursday. Otherwise, moderate trades dominate elsewhere. ...HISPANIOLA... Dry air aloft within northerly flow will support fair weather across the island through today and Thursday. Moderate trades are expected to persist. ATLANTIC OCEAN... A middle to upper level trough continues to progress eastward out of the Great Lakes and Mississippi River valley region towards the eastern US seaboard this morning. The trough supports a cold front extending from 30N77W to south Florida near 25N80W. Scattered showers and isolated tstms are occurring ahead of the front within 150 nm. The remainder of the SW North Atlc is under the influence of a surface ridge anchored by a 1028 mb high centered near 38N57W. To the E of the ridge, a cold front extends from 30N32W continuing to 28N36W where it becomes stationary to 25N42W then it starts to dissipate. Scattered showers and tstms are occurring W of the front from 25N- 29N between 50W- 59W. Weak surface ridging is elsewhere N of 20N. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos