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Weather Brief for September 25th, 2026, Coastal Flooding Potential

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Coastal Flooding Potential

  • A COASTAL FLOOD STATEMENT IS IN EFFECT for all of the Florida Keys for minor saltwater flooding of low elevation streets and lots.
  • This Friday morning, tides are running 7 to 9 inches higher than lunar/astronomical tide prediction charts indicate.
  • Minor saltwater flooding is expected to increase for both high tides (each day) through this weekend and early next week combination of being near the full moon phase and effects from a large non-tropical low pressure system (“Nor’easter”) containing gale force winds offshore the Mid-Atlantic and southern New England.
  • Eventually the higher high tide will transition to the late evening/early pre-dawn hours early beginning Sunday night.
  • Tides may eventually reach around  1 foot above normal predicted values.  Coastal Flood Advisories are likely to be required for the Upper Keys as early as Sunday night, and are likely to expand to include all of the Florida Keys by Monday night.
  • When Coastal Flood Advisories are issued, the peak tides are expected to reach between 6 and 12 inches deep in the lowest streets and lots in areas prone to King Tide flooding.

During those overnight higher high tides early next week, plan for the water to be around 6 inches higher than in a “typical” autumn season King Tide!  

Rainfall Outlook

  • The chances for rainfall exceeding one inch per day will be very low (10% or less) throughout the weekend through Monday of next week, then increase to about 1-in-3 by Tuesday, Wednesday and Thursday.
  • This return to above-normal rain chances will occur from a combination of a front over the Straits of Florida returning northward and returning deep tropical moisture out of the Caribbean, and a restrengthening upper level trough of low pressure across the southeast U.S. and Gulf.
  • It is too early to predict the exact timing of any heavy rainfall in relation to the overnight higher high tides at this time, but the combination of rainfall and tide effects could result in localized areas of more significant flooding during the middle part of next week.