Gusts over 40 mph, waves of 10 to 15 feet and a full moon will combine to force a storm surge of up to 4 feet onto Gulf Beaches this weekend, with significant coastal flooding possible even in bay waters. But the impact will depend on the exact timing.

The National Weather Service has issued a Coastal Flood Watch extending from Citrus County southward through Hernando County, Pasco County and Pinellas County from Saturday evening through Sunday evening. Coastal flooding is possible at any time during this period.

A strong – and cold – upper-level disturbance will dive all the way south from Canada into the northern Gulf of Mexico this weekend. The atmospheric imbalance created by the displacement of the energy, paired with the contrast in temperatures from the relatively warm Gulf of Mexico and the warmer Atmosphere above, will enable a vigorous storm to develop with gusty winds ahead and behind the associated cold front.

The forward momentum of the storm system combined with the gusty winds and rough seas will pile Gulf waters up against our shores. As a result, water levels are expected to run 2 to 4 feet above normal tide levels along the Gulf beaches, intracoastal and bay waters from Pinellas County northward. In Tampa Bay, water levels will build to 2 to 3 feet above normal tide levels.

Daniel Noah, the Warning Coordination Meteorologist from Tampa Bay’s National Weather Service says that there may be enough water to briefly flood Bayshore Blvd in Tampa, due to the combined push of water from the Gulf into Tampa Bay, but also from gusty winds and over wash.

The National Weather Service has categorized this as a minor to moderate event. In the case of a moderate event areas that typically flood should expect roads to become covered with water and some water may even seep into homes that are low-lying.

While the timing of high and low tide varies depending on where you live, the Gulf facing beaches should experience their high tide mid to late evening on Saturday night and late evening on Sunday. For Clearwater pass this means high tide will be at around 9:30 pm on Saturday and 10:30 pm Sunday night.

Typically, times of high tides are when we should expect to see the most coastal flooding, but as luck would have it the cold front and greatest storm surge should occur Sunday morning, right during low tide along most Gulf Beaches. This is good news and should temper what could have been a very significant flood event for our coast. With that said, the timing is not set in stone and a shift of just a few hours could make a big difference.
When the timing of storm surge coincides with high tide, flooding is enhanced. Currently this does not appear to be the case. The below graph shows the coastal flood forecast for Clearwater Beach. You can see the surge forecast in yellow which peaks at 4 feet on Sunday morning – that is a lot of water! But because it occurs at low tide the forecast flooding (black line) only reaches 1 foot.

Keep in mind this is only one location and because areas inside Tampa Bay will see their high and low tides a few hours later, that means the surge will not coincide as well with low tide. That could make for higher water. Pictured below is Ballast point which is on the north side of Tampa Bay. You can see the high tide is just after midnight Saturday night into early Sunday morning, about 3 hours after Pinellas County beaches.

If you are concerned about flooding in your area, you should check the tides here and change the location from the drop down to the town closest to you. Use this tool for coastal flooding predictions. Be sure to change the location.