Biscayne Bay Marine Forecast
| Today...Se Winds Around 5 Kt, Increasing To 5 To 10 Kt This Afternoon. Light Chop. A Slight Chance Of Showers And Tstms Early This Afternoon. A Chance Of Showers And Tstms Late. |
| Tonight...Sw Winds Around 5 Kt. Smooth. A Chance Of Showers And Tstms Early In The Evening. |
| Thu...S Winds Around 5 Kt, Becoming Se In The Afternoon. Light Chop. |
| Thu Night...Se Winds 5 To 10 Kt. Light Chop. |
| Fri...E Winds 5 To 10 Kt. Light Chop. |
| Fri Night...E Winds 10 To 15 Kt. A Moderate Chop. A Chance Of Showers And Tstms. |
| Sat...E Winds 5 To 10 Kt. Light Chop. A Chance Of Showers And Tstms Until Late Afternoon. |
| Sat Night...E Winds 5 To 10 Kt. Light Chop. |
| Sun...E Winds 5 To 10 Kt. Light Chop. |
| Sun Night...E Winds 5 To 10 Kt, Becoming Se After Midnight. Light Chop. Winds And Waves Higher In And Near Tstms. |
| Area Forecast Discussion National Weather Service Miami FL 305am EDT Wednesday August 12 2026 Synopsis Issued at 200am EDT Wednesday August 12 2026 Water vapor imagery this morning depicts several areas of enhanced convection within the northern stream flow. These clusters of storms were forced by weak shortwaves advecting around the northern edge of southern CONUS ridging and along a frontal boundary draped across the northern third of the country. As these waves continue on a general NW to SE track, they'll further amplify the eastern CONUS trough as it moves into the western Atlantic. This amplification will fracture the ridge that sprawls the Gulf and SW Atlantic into distinct areas of high pressure over the Gulf/Deep South and across the SW Atlantic. Global ensembles generally agree on this synoptic evolution through Thursday. Beyond Thursday we begin to look at shortwaves moving onto the western US coast and another moving through Quebec. Global ensembles have their greatest differences early in this window when it comes to how far north/south to place the Canadian shortwave, and later in the window with how the western CONUS trough cuts off (or doesn't) and how it eventually merges into the northern stream. Between these two features lies a large and anomalously strong ridge and the shape, movement, and positioning of this ridge will depend a lot on the evolution of the shortwaves. However, South Florida isn't expected to be on the edges of the ridge and instead firmly in its core, and thus the forecast isn't subject much to the current ensemble disagreements. .SHORT TERM... (Today through Thursday) Issued at 200am EDT Wednesday August 12 2026 With the fracturing ridge comes the disruption of the easterly steering flow as well as the continuity of the SAL. Today and tomorrow will likely feature slightly higher PWATs (Precipitable Waters) than yesterday and a very weak northerly steering flow. This will generally allow for a little more thunderstorm development along the seabreezes, little inland penetration, and a general southward movement of storms along the seabreeze. Expect the highest rain chances, though, to be across the southern half of South Florida where outflow and storms pile up and move very little due to the weak flow. Even with the most anomalous part of the ridge over the Gulf and Atlantic, column heigheights and temperatures are expected to still be in at least the top quartile of climatology for this time of year. This means we'll be dealing with both warmer than usual temperatures, and an increase in deep-layer moisture. Thus, a heat advisory is in effect for today for all of south Florida and will likely be needed for at least portions of south Florida again tomorrow. Long Term (Thursday night through Tuesday) Issued at 200am EDT Wednesday August 12 2026 The extended period becomes a little tricky, not because of the synoptic upper level pattern, but due to the timing of a wave of tropical moisture between pockets of SAL. In general though, global ensembles are within about 12 hours or so of each other with the arrival of the brief period of enhanced tropical moisture. What this ends up looking like is a day of more isolated storm coverage on Friday with at least some SAL (Saharan Air Layer) influence, increased rain chances on Saturday, and then a prolonged period of drier conditions Sunday into next week. Regardless of rain chances, the deep layer ridging mentioned above will become re-established and anomalously strong for this time of year. Highs in the middle to upper 90s, with heat indices well into Advisory levels are expected for much of the period. Marine Issued at 200am EDT Wednesday August 12 2026 Light winds and low seas are expected through the week. Daily wind increases to around 10 knots are expected in the seabreeze zone, as well as a light chop. Shower and thunderstorm activity will remain fairly isolated and mostly limited to the morning hours for the east coast and the evening for the Gulf. NOAA Miami FL Office: Watches - Warnings - Advisories FL... Heat Advisory from noon today to 7pm EDT this evening for FLZ063-066>075-168-172>174. AM...None. GM...None. |
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