Marine Weather Net

Gulf of Mexico from Seven Mile Bridge to Halfmoon Shoal Marine Forecast


5 - 10


5 - 10




10 - 15

The Marine Weather Forecast In Detail:
GMZ035 Forecast Issued: 428 AM EDT Mon Oct 21 2019

Today...Southeast Winds 5 To 10 Knots. Seas Around 1 Foot. Nearshore Waters Smooth To A Light Chop.
Tonight And Tuesday...Southeast Winds 5 To 10 Knots. Seas 1 Foot Or Less. Nearshore Waters Smooth To A Light Chop. Isolated Showers.
Tuesday Night...East To Southeast Winds Near 10 Knots. Seas Around 1 Foot. Nearshore Waters A Light Chop. Isolated Showers.
Wednesday...East Winds Increasing To 10 To 15 Knots. Seas Building To 1 To 2 Feet. Nearshore Waters Becoming A Light To Moderate Chop. Isolated Showers.
Wednesday Night...East Winds Increasing To 15 To 20 Knots. Seas 1 To 3 Feet. Nearshore Waters Becoming Choppy. Isolated Showers.
Thursday And Thursday Night...East To Southeast Winds 15 To 20 Knots. Seas 2 To 3 Feet. Nearshore Waters Choppy. Scattered Showers And Isolated Thunderstorms.
Friday And Friday Night...Southeast Winds Near 15 Knots. Seas 1 To 2 Feet. Nearshore Waters A Moderate Chop. Scattered Showers And Isolated Thunderstorms.
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Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas: GMZ005
428 AM EDT Mon Oct 21 2019

A pressure ridge in the Florida Straits will move northward, and establish itself across Southern Florida Monday through Tuesday night. A stronger ridge will build across the Southeastern United States Wednesday, before moving eastward and into the western Atlantic Ocean by the end of this week.

Gulf Stream
The Approximate Shoreward Edge of the Gulf Stream as of October 19th, 2019...
- 45 NM South of Dry Tortugas Light...on Loggerhead Key.
- 16 NM South of Cosgrove Shoal the Marquesas Keys.
- 6 NM South of Sand Key Key West.
- 2 NM South of Looe Big Pine Key.
- 4 NM South of Sombrero Key Marathon.
- 4 NM Southeast of Alligator Reef Islamorada. Less than
- 1 NM Southeast of Molasses Reef Key Largo.
- 3 NM East of Carysfort Reef Ocean Reef.
Area Forecast Discussion
National Weather Service Key West FL
421am EDT Monday Oct 21 2019

Under mostly clear skies and a steady southeast wind of 5 to 10 mph, temperatures are uniform in the lower 80s across the island chain. Meanwhile, local radars are only detecting isolated showers on the distant Straits of Florida beyond 20 nm south of the Marquesas Keys and Dry Tortugas. On our marine district, winds are southeast near 10 knots.

Short Term
(Today through Wednesday night) A deep layered western Atlantic ridge will build across South Florida and our region for the next couple of days. With strengthening large scale mid and upper level subsidence, moisture will be limited below 850 mb. Given scant moisture and no discernible low level undulation, only isolated rain chances will be retained beginning tonight. Temperatures will remain above normal with daytime highs in the upper 80s with overnight lows near 80 degrees.

Long Term
(Thursday through Sunday) The aforementioned western Atlantic anticyclone will lift northward, while a couple of low level undulations associated with higher moisture content track westward and across our region. In addition, an episode or two of large scale ascent and enhanced low level confluence and moisture flux will prompt a few spells of higher rain chances. However, due to timing uncertainty and the extent of low level convergence, will stream line middle of the road chance probability of precipitation including the potential of isolated lightning storms.

Light to gentle winds will prevail on all Keys coastal waters today through Tuesday, before gradually increasing and freshening Wednesday night through Thursday night. Hence, a Small Craft Should Exercise Caution headline/Advisory will likely be required on our marine district. Thereafter, winds will abate by the end of this week.

In 1964, the daily record low temperature of 64 degrees was last recorded in Key West. Temperature records date back to 1872.

NOAA Key West FL Office: Watches - Warnings - Advisories
FL...None. GM...None.