Marine Weather Net

Bayside and Gulf side from Craig Key to West End of Seven Mile Bridge Marine Forecast


TODAY

NW
WINDS
10 - 15
KNOTS

TONIGHT

NW
WINDS
15 - 20
KNOTS

SATURDAY

N
WINDS
25 - 30
KNOTS

SATURDAY NIGHT

N
WINDS
20 - 25
KNOTS

The Marine Weather Forecast In Detail:
GMZ032 Forecast Issued: 422 AM EST Fri Jan 28 2022

GALE WATCH IN EFFECT
Today...Northwest Winds 10 To 15 Knots, Increasing To Near 15 Knots During The Afternoon. Seas 1 To 2 Feet. Nearshore Waters A Light To Moderate Chop, Becoming A Moderate Chop.
Tonight...Northwest Winds 15 To 20 Knots, Becoming Northwest To North And Increasing To 25 To 30 Knots With Frequent Gusts Around 35 Knots After Midnight. Seas 1 To 3 Feet, Building To 3 To 5 Feet After Midnight. West Of The Marquesas Keys, Seas 2 To 3 Feet, Building To 5 To 6 Feet After Midnight. Nearshore Waters Choppy, Becoming Extremely Rough. Scattered Showers.
Saturday...Northwest To North Winds 25 To 30 Knots With Frequent Gusts Around 35 Knots. Seas 4 To 7 Feet, Except 7 To 10 Feet West Of The Marquesas Keys. Nearshore Waters Extremely Rough. Isolated Showers In The Morning.
Saturday Night...North Winds 20 To 25 Knots. Seas 3 To 6 Feet. West Of The Marquesas Keys, Seas 6 To 8 Feet, Subsiding To 5 To 6 Feet After Midnight. Nearshore Waters Very Rough.
Sunday...North Winds Near 20 Knots Early, Decreasing To 10 To 15 Knots In The Afternoon. Seas 2 To 5 Feet, Subsiding To 1 To 3 Feet. West Of The Marquesas Keys, Seas 5 To 6 Feet, Subsiding To 3 To 4 Feet. Nearshore Waters Rough, Becoming A Light To Moderate Chop.
Sunday Night...North To Northeast Winds 10 To 15 Knots. Seas 1 To 3 Feet. Nearshore Waters A Light To Moderate Chop.
Monday...Northeast Winds 10 To 15 Knots, Becoming Northeast To East And Increasing To Near 15 Knots In The Afternoon. Seas 1 To 3 Feet. Nearshore Waters A Light To Moderate Chop, Becoming A Moderate Chop.
Monday Night...East Winds 15 To 20 Knots. Seas 1 To 3 Feet. Nearshore Waters Choppy.
Tuesday...East Winds Near 20 Knots. Seas 1 To 3 Feet, Except 4 To 5 Feet West Of The Marquesas Keys. Nearshore Waters Rough. Isolated Showers.
Tuesday Night...East To Southeast Winds Near 20 Knots. Seas 1 To 3 Feet, Except 3 To 4 Feet West Of The Marquesas Keys. Nearshore Waters Rough. Isolated Showers.
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Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas: GMZ005
422 AM EST Fri Jan 28 2022

Gentle to moderate northwest breezes this morning will freshen this afternoon and evening. A powerful cold front is forecast to blast through the Keys waters late tonight, followed by very strong northerly winds through Sunday morning. Winds will decrease quickly Sunday afternoon. However, building high pressure over the western North Atlantic will lead to freshening northeast to east breezes Monday and Monday night, with fresh to strong easterly breezes prevailing Tuesday and Tuesday night.

Gulf Stream
The Approximate Shoreward Edge of the Gulf Stream as of January 27...
- 58 NM South of Dry Tortugas Light...on Loggerhead Key.
- 10 NM South of Cosgrove Shoal Light...off the Marquesas Keys.
- 7 NM South of Sand Key Light...off Key West.
- 6 NM South of Looe Key...off Big Pine Key.
- 8 NM South of Sombrero Key Light...off Marathon.
- 11 NM Southeast of Alligator Reef Light...off Islamorada.
- 6 NM Southeast of Molasses Reef Light...off Key Largo.
- 5 NM East of Carysfort Reef Light...off Ocean Reef.
Area Forecast Discussion
National Weather Service Key West FL
427am EST Fri Jan 28 2022

Extensive low stratus persists across the Middle and Upper Keys early on this Friday morning, while mostly clear skies prevail in the Lower Keys. Dewpoints have edged down in the mid 60s, causing the sea fog we observed Thursday over the Gulf side waters to lift into the current stratus deck. Temperatures along the island chain are hovering in the mid to upper 60s, and winds on land are from the northwest around 10 mph. Surface analysis depicts Arctic high pressure centered over eastern South Dakota, with weak low pressure lingering east of Florida. Aloft, a broad longwave trough remains in place across the entire CONUS east of the Rockies, with a shortwave dropping quickly southeastward through the Central Plains. The 06Z Key West special sounding sampled shallow moisture beneath a strong inversion near 5000 feet, with near normal PW of 1.11 inches.

Uneventful weather will continue today, as the stable and fairly dry airmass in place prevents any rainfall. There is uncertainty on when or if the persistent stratus across our eastern sections will dissipate, and if this cloudiness lingers longer than expected it would impact high temps. Will forecast the clouds to burn off later today, with highs reaching the mid 70s.

Guidance remains consistent in developing a deep trough over the eastern CONUS tonight into the weekend, with a powerful cold front blasting through the Keys late tonight. Rain chances do not appear quite as bullish as previously thought, especially for the Upper Keys which may see only a few showers. This front will usher in the coldest airmass of the season on strong NW/N winds. By Saturday night, northerly flow will transport a modified arctic airmass down the Florida peninsula into the Keys, with very little over water modification. We expect Sunday morning to see the coldest temps so far this winter, and probably the coldest temperatures in the Keys since February 2015. Lows Sunday morning should range from the lower 40s in the Upper Keys, to the mid 40s to near 50 in the Lower Keys, with highs on Sunday struggling to reach 60 degrees. Wind chill values will probably drop to near or below 35 degrees late Saturday night into early Sunday morning across the Upper Keys, which would require a Wind Chill Advisory. Sunday night will see very cool temps once again, although winds will diminish and temps will not be as cold as those observed Saturday night. Monday will begin a warming trend, with highs rebounding to near 70 degrees.

Thereafter, expect the warming trend to continue through next week, as the longwave trough and surface high pressure shift offshore into the western Atlantic, bringing a much more mild maritime airmass into the Keys from the east. Temps should return to near normal levels by Tuesday, then climb a few degrees above normal Wednesday and Thursday. Guidance differs on how much moisture return we will see in the brisk E/SE flow, and have continued with slight 10 to 20 percent rain chances for now.

Marine
Overnight observations report gentle to moderate NW breezes across the Keys coastal waters. Similar conditions will continue this morning, with winds beginning to increase during the afternoon. A powerful cold front is forecast to blast through the Keys waters late tonight, followed by very strong northerly winds through Sunday morning. A Gale Watch has been issued for late tonight and Saturday for all marine zones except Florida Bay. Winds will decrease quickly Sunday afternoon. However, building high pressure over the western North Atlantic will lead to freshening northeast to east breezes Monday and Monday night, with fresh to strong easterly breezes prevailing Tuesday and Tuesday night.

Fire Weather
A strong cold front will blast through the Keys late tonight, followed by windy, dry and sharply colder weather for the weekend. Minimum RHs are forecast to drop to between 30 and 40 percent in the Upper Keys on Saturday afternoon, accompanied by northwest to north winds around 20 mph. Very high dispersion is expected on Saturday as well, but ERCs should remain below Red Flag criteria. Northerly winds will decrease quickly by Sunday afternoon, but minimum afternoon RHs will drop to between 35 and 45 percent throughout the Keys.

Climate
In 1940, the daily record cold high temperature of 52F was recorded. Temperature records for Key West date back to 1873.

NOAA Key West FL Office: Watches - Warnings - Advisories
FL...None. GM...Gale Watch from late tonight through Saturday evening for GMZ032>035-042>044-052>055-072>075.