Marine Weather Net

E Gulf from 22N to 25N E of 87W including Straits of Florida Offshore Forecast


TODAY

ENE
WINDS
15 - 20
KNOTS

TONIGHT

E
WINDS
15 - 20
KNOTS

WED

ESE
WINDS
15 - 20
KNOTS

WED NIGHT

ESE
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
GMZ021 Forecast Issued: 1105 AM EDT Tue Sep 22 2020

Today...Ne To E Winds 15 To 20 Kt In The Afternoon. Seas 4 To 6 Ft. Scattered Showers And Isolated Tstms.
Tonight...E Winds 15 To 20 Kt. Seas 4 To 6 Ft. Scattered Showers And Isolated Tstms.
Wed...E To Se Winds 15 To 20 Kt. Seas 3 To 5 Ft. Scattered Tstms.
Wed Night...E To Se Winds 10 To 15 Kt. Seas 3 To 5 Ft. Isolated Tstms.
Thu...E To Se Winds 10 To 15 Kt. Seas 2 To 4 Ft.
Thu Night...E To Se Winds 10 Kt. Seas 3 Ft Or Less.
Fri...S To Sw Winds 10 Kt. Seas 3 Ft Or Less.
Fri Night...Se Winds 10 Kt. Seas 3 Ft Or Less.
Sat...Se Winds 10 Kt. Seas 3 Ft Or Less.
Sat Night...E To Se Winds 10 Kt. Seas 3 Ft Or Less.
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Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas: GMZ005
1038 AM EDT Tue Sep 22 2020

Fresh easterly breezes will linger for most of today and tonight. Moderate to occasionally fresh breezes will peak and lull from Wednesday through Thursday. Diminished southeasterly breezes are possible Friday through Saturday.

Gulf Stream
The Approximate Shoreward Edge of the Gulf Stream as of September 19...
- 25 NM South of Dry Tortugas Light...on Loggerhead Key.
- 35 NM South of Cosgrove Shoal Light...off the Marquesas Keys.
- 32 NM South of Sand Key Light...off Key West.
- 26 NM South of Looe Key...off Big Pine Key.
- 20 NM South of Sombrero Key Light...off Marathon.
- 12 NM Southeast of Alligator Reef Light...off Islamorada.
- 9 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
355pm EDT Tuesday September 22 2020

Currently - A ~1025 mb high is centered over the south and mid Atlantic states and is maintaining fresh east northeast to east breezes across the Keys. This fast flow of modified continental air has kept temperatures in the upper 80s, a bit below seasonal norms. Dew points have remains in the lower 70s. Despite ample warm and dry air above ~800 mb there is enough depth and moisture to contribute to a few patches of low topped showers have been able to develop along a few maritime boundaries.

Forecast - Over the next couple of days the high will spread eastward into the Atlantic off the Carolina Coast and gradually weaken. As a result, fresh winds will gradually relax and swing more easterly with the upstream maritime streamlines elongating considerably. Lower level flow will remain moisture rich below 850 mb. Despite the relaxing flow, as dew points gradually climb into the mid 70s, and temperatures push up back to normal, the potential for low topped showers will increase. Will maintain the ongoing trend to low chance pops.

All guidance points to a weak lower level trough lifting northward across Cuba beginning late Wednesday and slowly spread northward across our area through the back half of the weak. This will bring increasingly confluent low level moisture confluence. Expect rain chances and sky cover to generally trend upwards to mid to high chance through this period. Winds will generally become light to gentle out of the southeast to south, however there is some uncertainty depending on the exact structure and gradient pattern of the of the surface trough.

The trough will gradually lift north of our area and wash out heading into the weekend and early next week leaving a broad high pressure axis aligned across the southeastern United States and Florida. This will keep a light primarily southeasterly breeze across our area. The gradient will be fairly weak and mesoscale patterns will likely dominate sensible weather elements with temperatures remaining near to slightly above normal.

Marine
A healthy high pressure system centered over the southeastern and mid Atlantic states will result in fresh breezes on Keys waters this evening. Winds will gradually relax and shift more easterly over the next couple of day as the the high builds eastward off the Carolina coast. Winds will relax further heading into late week as a surface trough lifts northwards off of Cuba and into Keys waters. Expect rain chances to gradually increase due to the presence of the trough.

NOAA Key West FL Office: Watches - Warnings - Advisories
FL...Coastal Flood Advisory for FLZ076. GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075.