000 AXNT20 KNHC 170605 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 AM EDT Mon Apr 17 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Strong high pressure over the SW N Atlantic tightens the gradient behind a cold front extending from 30N40W to 21N47W to 19N58W, thus supporting gale force winds N of 28N between 45W and 55W with seas from 17 to 28 ft. Winds are forecast to diminish below gale by Monday night. Please refer to the high seas forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the E tropical Atlc near 06N11W and continues to 03N16W. The Intertropical Convergence Zone continues from 03N16W to 0N30W to 1S45W. Scattered to isolated moderate convection and tstms are from 2S to 4N W of 32W. ...DISCUSSION... ...THE GULF OF MEXICO... Broad surface high pressure anchored by a 1026 mb high over SW N Atlc waters extends a ridge axis SW across the Florida peninsula and Gulf of Mexico. This is supporting gentle to moderate easterly-southeasterly flow across the basin according to latest surface and scatterometer data, except in the E Bay of Campeche where a surface trough in the Yucatan Peninsula enhances the winds to fresh. Water vapor imagery show a middle to upper level short- wave trough which is supporting cloudiness and scattered to isolated showers over the W basin W of 93W. Cira LPW imagery show shallow moisture in the SE basin being advected from the Caribbean supporting cloudiness and possible isolated showers in that region. No major changes are expected through Wed. CARIBBEAN SEA... The pressure gradient between strong high pressure over SW N Atlantic waters and lower pressure over northern Colombia supports fresh to strong winds from 11N to 14N between 73W and 77W. Fresh to strong winds funnel across the Windward Passage tonight due to the high pressure N of the area. The area of high pressure is forecast to weaken by Monday night, thus acting to reduce the winds and seas. Water Vapor and CIRA LPW imagery continue to show very stable conditions over the NW Caribbean while SW winds aloft advects moisture from South America and the EPAC to the eastern basin. All this moisture is supporting showers E of 74W, including southern Puerto Rico, the Virgin Islands and Hispaniola. Shower activity for this region and Hispaniola is expected through Tuesday. An upper level trough over portions of Central America along with abundant low level moisture supports scattered heavy showers and tstms within 150 nm off the coast of Costa Rica and Nicaragua. Model guidance indicate that convection in this region will prevail through Monday night. ...HISPANIOLA... Trailing moisture associated with the passage of a former cold front N of the Island and tropical Atlc moisture moving across the Caribbean support cloudiness across the Island as well as isolated showers and tstms. Model guidance indicate the continuation of these showers through Tue. ATLANTIC OCEAN... A cold front extends from a 986 mb center of low pressure N of the area near 33N47W and continues to 30N40W to 21N47W to 19N58W. A strong pressure gradient between a high in the SW N Atlc and the front supports gale force winds N of 29N. See the special features section for further details. Otherwise, a 1009 mb low is near 26N18W with associated trough extending SE to 22N16W. There is no shower activity associated with the low. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos