000 AGXX40 KNHC 021838 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 238 PM EDT Mon Oct 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... Middle to upper level low across the basin past few days is now diving SW along W coast of Yucatan Peninsula and into isthmus region. Associated llvl trof to the E has sharpened past 24 hours and shifting W across Yucatan and now into central Gulf waters. Very active convection continues to shift WNW and Yucatan and into central Gulf and has also aided in freshening ESE winds across the Straits. Weak frontal boundary has shifted SW into NE Gulf overnight but sharp troughing not allowing for much penetration across central Gulf, but ha moved farther S across far E gulf and S central FL to Sanibel I area. Meanwhile llvl trough moving NW into SE TX coastal waters while coastal troughing persists offshore of Veracruz. Strong high pres building into the basin and forcing weak front across area in a back door manner is maintaining strong Ely flow across NE portions veering SE into LA, and bridging over front across SE and S central portions. Seas look to be 6-9 ft across the NE third of basin and likely not higher as winds have slowly veered past 24 hours and limited time for wave growth. Seas 3-5 ft elsewhere except 2-3 far W central waters. Strong high pres across Ern seaboard will continue to produce strong pres gradient across the N portions of the basin for the next few days as troughing currently described moves W and allow for high and associated winds to build W to 94W by Tue. As this broader wind field evolves, large seas 7-9 ft will spread across larger area N of 24N with peak seas to around 10 ft. Models suggest llvl perturbation will move through the Straits late Tue through Wed and tighten pres gradient, increasing winds to the N of this pert to 25-30 kt with seas building 10-12 ft in this shifting region. The pressure gradient will start to relax by the end of the week with winds diminishing to moderate throughout by Fri night. Seas will begin to subside as a result, to 6 to 9 ft by Fri night. Central American gyre is forecast to develop by end of week and likely to influence weather across the Gulf over the weekend. Models not in good agreement attm and will look for trends in coming days. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Scattered showers and thunderstorms across the NW Caribbean overnight have shifted NW and mainly across the Yucatan and into the central Gulf past several hours, leaving scattered showers and isolated tstorms across NW portions with moderate ESE to SE winds. A tropical wave along about 73-74W continues to interact with an TUTT low shifting WSW over Jamaica attm, with EPAC monsoonal flow beginning to spread across Panama and Costa Rica and into SW Carib where it is igniting with and ahead of the tropical wave. The wave will continue to move W next few days and become difficult to identify as it slowly become absorbed in the developing Central American gyre throughout the week. Very active weather is expected across SW and W portions during this time. Mainly moderate E to SE flow and seas of 3 to 5 ft dominate the basin, except 1 to 3 ft seas in the SW Caribbean where SE winds are gentle. A tropical wave currently along 51W/52W will move into the Tropical N Atlantic by early Tue, then the E Caribbean by early Wed. Moderate E to SE trades in the wake of the current tropical wave will freshen and become easterly by Tue in advance of this next wave. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A cold front extends from 31N60W to weakening 1014 mb low pressure near 26.5N74.5W then continues SW as a stationary front through the N central Bahamas to the upper Keys. Strong high pressure along Ern seaboard continues to build down N of the front with strong NE to E winds and 8 to 13 ft seas N of front W of 65W. Strongest winds and highest seas now across N semicircle of filling low which will shift WSW through the Bahamas and across S FL next 24 hours. To the SE, a surface trough, part of N extension of central Carib tropical wave and upper low interaction. extends from NW Haiti to 25N71W, with scattered showers and tstorms occurring E of the trough, and shallow convection being forced by fresh NE winds to the W. The cold portion of the front will continue eastward while the remainder stalls along 27N/26N during the next 48 hours as the strong high to the N builds across the W Atlc. Fresh to strong NE to E winds will continue to spread southward in its wake through mid-week covering the waters N of 25N where seas will be continue 8 to 13 ft, but with 8-9 ft seas spreading NE across far NE waters. Fresh easterly flow will prevail S of 25N W of 70W along with 6 to 8 ft seas by mid-week. The pressure gradient will weaken significantly by the end of the week as the remnants of the frontal boundary drift N and the strong high shifts E into the central Atlc. This will allow for winds to relax to gentle to moderate across the basin S of the old boundary, and remain fresh to strong N of the boundary as it shift to along 29-30N by Fri. Seas will slowly subsiding to 6 to 9 ft by Fri afternoon. The Central American gyre will lift N to NNE into the NW Carib and possibly SE Gulf Fri through Sat and induce moderate SE winds across much of the area, however models not currently in agreement so precise forecast uncertain attm. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.