marine weather discussion NWS TPC/National Hurricane Center Miami FL 125 am EDT sun Jul 12 2009

Marine weather discussion for the Gulf of Mexico...Caribbean Sea and southwest north Atlc S of 31n W of 55w.

Gulf of Mexico... east to northeasterly upper level flow at the se periphery of a broad upper level ridge over the south Central Plains of the United States is providing deep layer subsidence across the Gulf...helping to sustain a surface ridge across the N Gulf along 30n. Winds are light and variable in the vicinity of the surface ridge. Anticyclonic flow around the ridge is associated with a broad swath of E winds of 10 to 15 kt across the southern half of the Gulf...highest near The Straits of Florida. These winds are generating wind wave heights of 3 to 5 ft...highest in the Florida Straits. However...20-25 kt winds are found in the SW Gulf in the vicinity of a surface trough being enhanced by terrain-induced northeasterly flow W of the Yucatan Peninsula. This surface trough is forecast to track across the SW Gulf S of 22n through this afternoon...followed by se winds around 15 kt...and will likely be accompanied by scattered thunderstorms. The surface ridge will gradually sink southward across the Gulf next week...with a weakening pres gradient and winds diminishing somewhat across the S Gulf. However...NE winds to 20 kt will be a common occurrence during the evenings near the W coast of the Yucatan Peninsula... enhanced by nearby terrain variations.

Caribbean... fresh to strong trade winds will affect the Caribbean during the next several days between the surface ridge over the Gulf of Mexico and central north Atlc...and broad low pressure over northern South America. The primary focus of these stronger winds will be from 11n to 18n W of 68w. The strongest winds will be found near the coast of Colombia...where winds will periodically reach 30 kt into next week. Seas of 8 to 11 ft will also be common from 11n-18n W of 70w through next week...with maximum seas 13 to 14 ft near the coast of Colombia by the middle of next week. Also...NE winds to 20 kt will occasionally occur in the Windward Passage during the several days. A tropical wave entering the W Caribbean from W Cuba to Panama will move W at 20-25 kt across the W Caribbean during the next couple days. Showers and thunderstorms will increase in areal coverage and intensity near the N half of the wave during the next couple days as the tropical wave interacts with atmospheric instability near an upper level trough over the NW Caribbean. By Tuesday morning...another tropical wave...currently along 40w...will have accelerated to 20-25 kt...and enter the E Caribbean...followed by increased E winds...and a strong surge of Saharan air.

Atlc... an upper level trough along an axis from 31n68w to 21n75w is associated with a surface trough extending from 26n71w across the central Bahamas to 22n78w. NW of the surface trough...light and variable winds will persist. However...by early Tue...SW winds will increase to 15 to 20 kt across the NW part of the SW north Atlc in response to a deepening low N of the discussion area. Otherwise...a surface ridge over the central north Atlc will maintain NE to E trade winds of 15 to 20 kt across the tropical N Atlc and far southern portions of the SW north Atlc for the next few days. Weak perturbations rotating around the ridge will locally enhance these winds to around 20 kt...with seas in the 6 to 8 ft range. A tropical wave currently along 40w is moving W 15-20 kt. A strong low to middle level wind surge follows the wave...and will move across the tropical Atlc over the next few days. The Post-wave E winds of 20 to 25 kt will generate building seas across the tropical N Atlc N of 13n/14n throughout the week...forcing the wave to tilt from NE to SW with time. These fresh to strong trade winds...and significant haze in Saharan air will dominate the tropical Atlc by the middle of the upcoming week with this wind surge. The stronger winds will build seas to 8 ft.

Warnings

Atlc... .None.

Caribbean... .None.

Gulf of Mexico... .None.

Forecaster cohen. Tropical Prediction Center.