Marine Weather and Tide Forecast for Miami Beach, FL

SHORT TERM
(Today through Tuesday)
Issued at 119 AM EDT Mon May 18 2026

South Florida is going to be sandwiched between an upper level low centered near the Bahamas and a ridge of high pressure over the deep south and Gulf. The low over the Bahamas will usher in some positive vorticity pulses from the northeast and increase instability across the area. The easterly flow has a chance to become more dominant than yesterday, meaning that the Gulf breeze may not be able to move inland at all. However, much of the guidance does have it forming and getting stuck just barely on land. If this boundary does move more inland it will get pinned no further than along the metro areas of Collier county and Naples. SBCAPE is forecast to be 2000-3000 J/kg with steep low level lapse rates of 8-9 C/km and 500mb temps near -10 deg C. The dry air column has mostly been eroded, although some level of dry air still remains in the mid-levels along with an inverted-V profile on model soundings. This suggests that a couple of storms could become marginally severe again via wind gusts.
Additionally, with these steep low level lapse rates and increased CAPE, updraft health has a good chance to be sustained even with the inhibition of the upper level ridge.

Given the upper level ridge presence, the risk for strong to severe storms is highly conditional again today, but with the parameters explained above, support is there for an isolated severe thunderstorm or two occurring along the Gulf breeze where the strongest lift and near-surface convergence occurs. Both severe winds and quarter-size hail will be possible today.

On Tuesday, the weather pattern remains largely the same although its more uncertain to determine severe potential. The easterly flow will remain in place and result in another day with a Gulf breeze that gets trapped from advancement, but 500mb temps will rise a couple of degrees to -8 deg C and some extra dry will filter in the mid-levels, which will lower instability. Nevertheless, typical wet season scattered showers and storms are still expected on Tuesday with most of the activity occurring in Southwest Florida with the ongoing easterly flow regime.

High temperatures for today and Tuesday will again range from the mid to upper 80s in Southeast Florida to the low to mid 90s for Southwest Florida.

LONG TERM
(Tuesday night through Sunday)
Issued at 1257 AM EDT Mon May 18 2026

Longwave ridging will be the dominant pattern aloft for the eastern CONUS during the middle portion of the week. Florida will find itself in between an H5 centroid to its west over the southern Gulf and an H5 centroid to its east near Bermuda. Within the overall ridging pattern, ensemble guidance is in pretty good agreement of showing a cut off low meandering around the northern Caribbean just east of the Bahamas. This area of low pressure will provide increased forcing for storms over the Atlantic waters as several lobes of vorticity advect westward near the vicinity of the Florida coastline. Florida will remain under rich moisture through the period, but some deeper pockets look to raise PWATs to near 1.8 inches, which is within the 75th percentile for this time of year. At the surface, winds will remain mostly easterly, but wind speeds will be slightly weaker than in the beginning of the week as pressure gradients relax across the eastern seaboard.
As a result of this predominant easterly flow, the Gulf breeze won't be able to advance as far east. This will result in most afternoon thunderstorm activity favoring interior and portions of southwest Florida each day. Overall, PoPs will generally be in the 30% to 40% range across the peninsula each day, with higher 55% to 65% PoPs along the sea breeze convergence zones. Main threats will be frequent lightning, locally heavy downpours, and gusty winds.

Despite the cutoff low nearby, 500 mb heights will actually be between 586 to 589 dm across South Florida, which is near to slightly above average for this time of year. This will in turn lead to slightly above normal temperatures area wide, with high temperatures in the upper 80s and low 90s. With moisture staying steady throughout the week, heat indices will remain in the upper 90s and lower 100s through the period as well. Zooming into the forecast a little bit, diurnal heating will drive most of these high temperatures each afternoon. But, with increased chances of showers moving onshore from the Gulfstream during the morning (particularly for the middle part of the week), cloud cover and rain may keep things cooler over certain spots during the day.
Conversely, increased cloud cover and rain during the nighttime hours may suppress radiational cooling and keep things slightly warmer overnight. For the most part, widespread Moderate HeatRisk (level 2 of 4) is expected each day. However, long range ensembles are indicating that pressure heights will increase slightly as longwave ridging shifts east and the cut off low dissolves. This will result in warmer temperatures for the weekend, with the NWS Prototype Probabilistic HeatRisk tool showing a 40 to 50 percent chance of Major heat impacts for the east coast metro areas.

AVIATION
(12Z TAFS)
Issued at 656 AM EDT Mon May 18 2026

Breezy easterly winds will continue with SHRA coverage forecast to increase along the east coast of South Florida over the next few hours before activity pushes inland by 17-19z. Wind gusts will rise up to 20-25 kts as well. At KAPF, SHRA/TS coverage will occur after 18-19Z.

MARINE
Issued at 119 AM EDT Mon May 18 2026

A moderate to fresh easterly breeze will remain established across the local waters early this week. Scattered showers and storms will be possible each day with extra activity expected for the Gulf waters compared to the Atlantic waters. Periods of rough seas and gustier winds are expected in and around thunderstorm activity.
Atlantic seas early this week are expected generally at 3-4 feet with Gulf seas of 2 feet or less.

BEACHES
Issued at 119 AM EDT Mon May 18 2026

A high risk for rip currents continues for all of the Atlantic beaches early this week as breezy onshore winds persist.

PRELIMINARY POINT TEMPS/POPS
Miami 87 78 87 77 / 30 30 40 20 West Kendall 88 75 89 74 / 40 30 50 10 Opa-Locka 88 77 88 77 / 30 30 40 20 Homestead 87 77 88 77 / 30 40 40 20 Fort Lauderdale 86 78 86 78 / 30 40 40 30 N Ft Lauderdale 85 77 85 77 / 30 40 30 20 Pembroke Pines 89 78 90 78 / 30 30 30 20 West Palm Beach 86 77 86 77 / 30 40 30 10 Boca Raton 86 78 86 78 / 20 40 30 20 Naples 92 74 92 74 / 70 20 90 10

MFL WATCHES/WARNINGS/ADVISORIES
FL...High Rip Current Risk through Tuesday evening for FLZ168-172-173.

AM...None.
GM...None.