000 AGXX40 KNHC 021016 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 616 AM EDT Sat Sep 2 2017 Marine Weather Discussion for the Gulf of Mexico, Caribbean Sea, and Tropical North Atlantic from 07N to 19N between 55W and 64W and the Southwest North Atlantic including the Bahamas. ...GULF OF MEXICO... Deep layered trough across the NW Gulf this morning with convergent band of moisture ahead of it strong across NE Gulf where active convection has shifted NE into FL and farther NE overnight. Weak high pres resides over the NE Gulf just to the E of the previous active weather yielding gentle flow across most of the basin. Yucatan thermal trough has shifted W into the Bay of Campeche with strong winds and building seas to 4-5 ft per recent altimeter pass. Otherwise sea 3 ft or less. Abundant tropical moisture will continue to advect N and NW across the Yucatan Channel and Straits today for continued active weather. High pressure will meander across the N central and NE Gulf through early next week while a trough develops in the SW Gulf and drifts W towards the Mexican coast Tue and Wed. An area of low pressure may form in the southwestern Gulf along the trough. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Weak high pres across the W Atlc just E of Bermuda inducing just enough pres gradient across the basin to produce strong winds S of 14N off the coast of Colombia, with seas to 8 ft. Otherwise seasonally mild conditions across the basin. The weak ridge N of the area will support pulsing fresh to strong trade winds off the coast of northwest Venezuela and northeast Colombia each night through early Mon. Seas will build to 6-8 ft toward the early morning hours with the strongest winds. Moderate to fresh winds are expected across the Gulf of Honduras at night through the forecast period. Gentle to moderate NE-E winds and seas in the 4-6 ft range will prevail across the Tropical N Atlantic waters through late Sun before the approach of Irma. Major hurricane Irma will approach the Tropical North Atlantic zone Mon and forecast to begin to veer WNW and across the Leewards Atlc waters Tue night and Wed. The latest ECMWF model has shifted S of previous runs and now is just offshore of the far N Leewards late Tue through Wed. Thus it is still possible that the Leeward Islands may be impacted by Irma and all interests should stay tuned to developing forecasts. ...SW N ATLANTIC INCLUDING THE BAHAMAS... TA weak and narrow ridge extends SW into the area from high pres centered E of Bermuda, while a lingering frontal boundary is strung out just to the NE of the area waters. Nly swell generated from low that developed from PTC 10 across the N Atlc is affecting most of area N through NE of Bahamas, with overnight buoys and altimeter obs showing the swell 2-4 ft above guidance, with strongest energy aimed at NE Carib islands and farther Ewd. Have tried to adjust low guidance in the short term and will likely produce high surf across the islands tonight and Sun as I calculate 5-6 ft swell at 15 secs arriving. Moderate to fresh E trades will prevail S of 22N and into S Bahamas, while gentle to moderate winds will prevail elsewhere through Mon. Major hurricane Irma is expected to approach the Leewards Tue and current forecast has this major hurricane moving WNW and just offshore of the outer islands Tue night and Wed. Models continue to adjust, with latest ECMWF having shifted S of recent runs and very near the N Leewards. This model is now an outlier and reducing confidence attm. Majority of guidance remains near recent NHC forecasts for Irma and latest forecast has adjusted slightly S to account for the shift by ECMWF. All interests across the NE Carib and Bahamas should continue to closely monitor Irma as all global models show a major hurricane with expanding wind field after moving W of 70W. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *For detailed zone descriptions, please visit: http://www.nhc.noaa.gov/abouttafbprod.shtml#OWF Note: gridded marine forecasts are available in the National Digital Forecast Database (NDFD) at: http://www.nhc.noaa.gov/marine/grids.php For additional information, please visit: http://www.nhc.noaa.gov/marine $$ .Forecaster Stripling. National Hurricane Center.