What to Know
- This weekend’s water levels could be the highest king tide of the season so far
- Heavy rain, isolated flash flooding: 2 to 4 inches possible this weekend into early next week, with locally higher amounts.
- Gusty coastal winds: Sustained winds over 25 mph and gusts over 40 mph are possible this weekend.
South Florida is heading toward some of its highest tides of the year this weekend and early next week but it’s the combination of the lunar cycle and weather conditions that ultimately determine when the worst of the even hits.
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Stronger onshore winds (east winds) and rain Sunday could worsen flooding before the predicted tidal peak arrives early next week.
The lunar cycle is the main driver of the King tides at the end of the day and this driver is pointing to the peak coming on Tuesday. It’s complicated.
The full moon occurs at 12:11 a.m. Monday, Oct. 26, but the King Tides very well may peak roughly a day after the full moon.
Why the delay? The moon and the ocean don’t keep exactly the same schedule…there is a lag.
During full and new moons, the sun, Earth and moon are roughly aligned. This creates a stronger gravitational pull on the ocean, creating a larger difference between high and low tide.
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The ocean’s response is more complicated than water simply rising beneath the moon. Tidal waves travel through ocean basins and across shallow coastal waters. Water depth, the shape of the coastline and friction affect their timing. The lunar tides can therefore combine most strongly at a particular location after the moon reaches its full phase. A delay of a day or two is common, although it varies by location.
Current weather conditions can affect the timing of peak high tides too.
Stronger east to northeast winds, like the ones in the forecast this weekend, especially Sunday, will likely push additional water toward the Atlantic coast, raising water levels above the astronomical tide predictions. That combination creates a drainage problem as rainwater has a harder time escaping when the waterways it normally drains into are already high. Throw in some heavy rain and water could accumulate more quickly and linger longer on vulnerable streets.
However, Tuesday’s “predicted” tidal maximum does not necessarily mean Tuesday will bring the worst flooding.
Stronger winds and heavier rain could produce greater impacts Sunday or Monday, even with slightly lower astronomical tides. All the more reason to stay with NBC6 as we update you on all the factors.
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