marine weather discussion NWS National Hurricane Center Miami FL 1227 PM EDT Fri Jul 21 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...
Convection is increasing across much of the N half of basin late this morning as an upper low is shifting slowly wwd across the NE Gulf and interacting with ample llvl moisture about both sides of lingering sfc trough. This activity expected to continue through tonight. W Atlc ridge extends wwd along 28n and very weakly across FL and weakly across the Gulf along about 27n, with a sympathetic high having formed near 26n86n. 12z obs suggested seas 1-2 ft across entire basin except 3-4 ft across SW portions in response to Yucatan thermal trough shifting W overnight. With weak pres pattern to prevail across the basin next several days, this thermal trough will dominate the Yucatan and SW Gulf during the period. A very energetic tropical wave moving across Honduras and Nicaragua this morning will enhance Yucatan cnvtn this afternoon through tonight and then across W Bay of Campeche and adjacent Mexican areas through Sat night.
Otherwise, the weak ridge will dominate through Saturday producing gentle to moderate winds and seas of 1 to 3 ft, with the exception of the eastern Gulf, where variable winds and seas of 2 ft or less will prevail. On Sunday, as the ridge builds westward, expect moderate to locally fresh se to S winds, and seas of 3 to 5 ft across much of the W and SW Gulf through Tuesday night, where the pressure gradient will be tighter.
...Caribbean Sea and tropical N Atlantic from 07n to 19n between 55w and 64w...
Very energetic tropical wave, former ts Don, has moved into Nicaragua and Honduras with accompanying wind surge slowly diminishing impacts across the W Carib waters and Gulf of Honduras. Squalls and tstorms have moved will inland and weakened past several hours. Seas were 6-9 ft across waters off of Nicaragua and 5-7 ft off of Honduras at 12z and are slowly subsiding. This wind surge shifted area of Max wind and seas from typical location off of Colombia to this area overnight and this morning. Meanwhile farther E, trailing strong ENE extend to S of Hispaniola and the S Mona Passage where seas were 6-7 ft with likely areas to 8 ft. PR buoys showing seas at 5 ft at 12z and down slightly from overnight. Large aew complex covers from about 72w to the waters E through NE of the islands as secondary vort is riding WNW up the back side of leading broad wave along 71w and will transport this moisture across the NE Carib through tonight. As this aew complex moves across the remainder of basin through the weekend, peak winds will persist across the S central portions of the basin, in normal location where seas will fluctuate 7-9 ft. Diurnal processes to enhance fresh E trades S of Hispaniola through the weekend. Models show Atlc ridge shifting slightly W by Mon and strengthening pres grad just enough to hint at 30 kt early morning peak winds off of Colombia, with seas to 10 ft.
...SW N Atlantic including the Bahamas...
High pressure ridges across the W Atlc along 28-29n to central FL yielding moderate to fresh trades S of 23n E of Turks and Caicos becoming se to S winds through the Bahamas. Wind surge associated with the broad tropical wave complex across the E and NE Carib kicked up seas 6-7 ft with isolated spots to 8 across the far se waters from N of PR to N of leewards. Elsewhere seas relatively tranquil at 4-5 ft except # ft or less through Bahamas and 2-3 ft across FL and GA coastal waters. TUTT low across and just E of central Bahamas inducing increasing cnvtn attm and looks to be an active day. Squalls and tstorm associated with wave energy moving WNW across the waters NE of the leewards will shift across these waters late this afternoon through tonight. Models in good agreement that ridge will remain generally intact into early next week with little change to conditions, and modified mainly by passing aews.
.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.
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.Forecaster stripling. National Hurricane Center.