Marine Weather Net

Florida Bay including Blackwater and Buttonwood Sounds Marine Forecast


TODAY

SW
WINDS
10 - 15
KNOTS

TONIGHT

FRIDAY

WSW
WINDS
20
KNOTS

FRIDAY NIGHT

W
WINDS
20
KNOTS

The Marine Weather Forecast In Detail:
GMZ031 Forecast Issued: 437 AM EDT Thu Oct 28 2021

SMALL CRAFT SHOULD EXERCISE CAUTION FOR INCREASING WINDS ...SMALL CRAFT ADVISORY LIKELY WILL BE REQUIRED TONIGHT...
Today...Southwest Winds 10 To 15 Knots, Increasing To 15 To 20 Knots. Bay Waters A Light To Moderate Chop, Becoming Choppy. Isolated Showers And Thunderstorms In The Morning, Then Scattered Showers And Isolated Thunderstorms In The Afternoon.
Tonight...Southwest Winds Increasing To Near 20 Knots. Bay Waters Becoming Rough. Numerous Showers And Scattered Thunderstorms.
Friday...Southwest To West Winds Near 20 Knots. Bay Waters Rough. Isolated Showers.
Friday Night...West Winds Near 20 Knots. Bay Waters Rough. Isolated Showers.
Saturday...West Winds 15 To 20 Knots. Bay Waters Choppy. Isolated Showers.
Saturday Night...West To Northwest Winds 10 To 15 Knots, Becoming Northwest To North And Decreasing To Near 10 Knots. Bay Waters A Light To Moderate Chop, Becoming A Light Chop. Isolated Showers.
Sunday...Northwest Winds 5 To 10 Knots. Bay Waters Smooth To A Light Chop.
Sunday Night...Northwest To North Winds 5 To 10 Knots, Becoming North To Northeast. Bay Waters Smooth To A Light Chop.
Monday...Northeast To East Winds 5 To 10 Knots. Bay Waters Smooth To A Light Chop. Isolated Showers.
Monday Night...Northeast To East Winds Near 10 Knots. Bay Waters A Light Chop. Isolated Showers.
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Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas: GMZ005
1050 AM EDT Thu Oct 28 2021

A frontal boundary will approach the Florida Keys this afternoon, resulting in freshening southwesterly to westerly breezes. The front will to push through the marine zones of the Keys overnight, with increased rain and thunder chances as the front passes. Fresh to strong breezes will prevail across the coastal waters through Saturday. Breezes will slacken Saturday night through early next week, with below normal rain, and near- nil thunder chances expected.

Gulf Stream
The Approximate Shoreward Edge of the Gulf Stream as of October 27...
- 20 NM South of Dry Tortugas Light...on Loggerhead Key.
- 17 NM South of Cosgrove Shoal Light...off the Marquesas Keys.
- 17 NM South of Sand Key Light...off Key West.
- 20 NM South of Looe Key...off Big Pine Key.
- 24 NM South of Sombrero Key Light...off Marathon.
- 28 NM Southeast of Alligator Reef Light...off Islamorada.
- 20 NM Southeast of Molasses Reef Light...off Key Largo.
- 15 NM East of Carysfort Reef Light...off Ocean Reef.
Area Forecast Discussion
National Weather Service Key West FL
550am EDT Thu Oct 28 2021

As winds shifted to the south to southwest yesterday, the drier lower to mid-level air that has persisted since yesterday morning started to recede back to the north and more moist air started to be ushered in. Between yesterday morning's and yesterday evening's soundings, the large dry air pocket was noticeably smaller. Satellite derived PW indicates that it has increased to an estimated 1.8-1.9 inches across the Florida Keys. While there has not been an abundance of shower activity overnight, a few showers have moved over the islands and KBYX is currently detecting isolated showers in the Gulf Waters and in the Upper Keys and adjacent nearshore waters. The surface front associated with the deep longwave trough located in the Mississippi Valley area has reached the western Florida Panhandle and extends southwest into the Gulf of Mexico. Winds have already started to increase in response to the approaching front. Marine observation platforms are currently recording winds ranging from 8 to 16 knots, with the highest winds in the western waters.

.FORECAST... As the frontal boundary edges closer to the Florida Keys through the afternoon, breezes will continue.nue to freshen. While there will be increased moisture, instability, and a source of lift with today's frontal passage, the front will start to lose its upper- level support as it approaches from the northwest. The Panhandle down to central Florida will possibly have a few strong to severe storms, however, we are not expecting storms of that caliber as far down as the Keys due to this. A band of showers and thunderstorms will advance towards Gulf Waters from the northwest this afternoon and push to the southeast across the island chain overnight tonight. An increase in shower and thunderstorm coverage is expected starting this afternoon, and measurable rainfall will likely occur in most island communities tonight.

After the frontal passage, the Florida Keys and surrounding coastal waters are in for a windy start to the weekend. As the parent low continues eastward across the eastern U.S. through around Saturday, winds will remain elevated due to the tightened gradient. Much drier air will filter in behind the front and dewpoints will drop into the mid 60s. Temperatures are also expected to drop a few degrees. This drier air will usher in more comfortable conditions, as well as reduce shower activity greatly through the beginning of the week. Forecast soundings show a healthy subsidence inversion setting up during this time, which will further inhibit shower development. A decrease in winds is expected starting Saturday night as the low pressure weakens and shifts to the northeast. High pressure will begin to build into the area as this occurs, which will shift our winds to the northeast. This will allow for a slight increase in moisture and help us return to near normal rain chances and temperatures by mid-week next week.

Marine
A frontal boundary will approach the Florida Keys tonight and cause freshening southwesterly to westerly breezes. The front is expected to push through the marine zones of the Keys from west to east, with increased shower and thunderstorm coverage likely as the front passes. Small Craft Should Exercise Caution in all waters today as winds increase in response to this frontal passage. A Small Craft Advisory will likely be needed for all waters tonight, which will is expected to extend through Saturday. Breezes will slacken Saturday night through early next week, with below normal rain and thunder chances expected.

Climate
On this day in 1892, the daily record cold high temperature of 70F was last recorded in Key West. This is also tied for the coldest high temperature ever recorded in October. Temperature records date back to 1872.

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