The 2024 Hurricane Season is predicted to be well above normal due to two primary factors: El Nino and warm ocean water.
Hurricane Ian approaching Florida West Coast
The Averages
On average, a tropical storm will pass within 50 miles of Tampa Bay about once every other year, while hurricanes pass within 50 miles about once every 4 years and major hurricanes, about once every decade. Direct major hurricane hits on Tampa Bay are rare, with only 2 ever recorded; a Cat 4 storm in 1848 and a Cat 3 storm in 1921.
Worst Case Scenario
A 2010 study called “Project Phoenix”, funded by FEMA, took a look at the Tampa Bay area if it was directly hit by a Cat 5 hurricane. In this “worst case” scenario, power outages would be widespread with all of Pinellas County being without power and with Pasco and Hillsborough Counties experiencing nearly total power outages as well. The associated storm surge would be as high as 26 feet in Tampa, 24 feet in Apollo Beach, and 20 feet in St. Petersburg.
Project Phoenix
All told, a Cat 5 storm could result in up to 2,000 people dead, 2 million injured, and almost 500,000 homes and businesses destroyed. All three bridges between Tampa Bay and the Courtney Campbell Causeway would “sustain either structural damage or have their approaches washed away by water and waves.”
What is the risk for Tampa Bay in 2024?
It is not all bad news for this season, however. Although there is an overall higher risk for tropical cyclone activity in the North Atlantic this season, perhaps even setting records, the risk for a hurricane directly hitting the Tampa Bay area may actually be no greater than average, and possibly slightly less than average.
Based on analysis from Colorado State University, the risk for a named tropical storm passing within 50 miles of Pinellas County this year is about 64% which is 10% higher than the long-term (1880-2020) average of 54%. The risk for a hurricane passing within 50 miles of the coast, however, this season is 26% which is actually slightly lower than the long-term average of 27%. The risk for a major hurricane (Cat 3-5) passing within 50 miles of the coast this year is 10%, also slightly below the long-term average of 11%.
Analog Years
The North American Multi-Model Ensemble (NMME) is a seasonal prediction system that combines data from computer climate models in the U.S. and Canada to produce monthly and three-month averages. The NMME has been releasing global forecasts every month since 2011, and its information is used by NOAA to inform their seasonal outlooks.
The best analog years for the 2024 hurricane season based on NMME sea surface temperature anomalies are 1970, 1999, 2007, 2010, and 2011. The resulting outlook suggests hurricane tracks are more likely in the red-shaded areas vs. blue-shaded areas. Most of Florida is in the blue zone, except for extreme South Florida and the Keys.
Source: Tropical Tidbits.com
Wind Radius
With hurricanes, size does matter. Typically, for a Cat 1 hurricane, the radius of hurricane force winds will extend out only about 25 miles, with only about 10% of storms being large enough to have hurricane force winds out to over 45 miles. Major hurricanes tend to be larger, with hurricane force winds extending outward about 45 miles, on average, with a few extending outward some 75 miles or more. Damaging winds of 50-64 kt (58-73 mph) usually extend out farther, typically to about 80-110 miles from the center and often cause roof damage, uprooted trees, and significant power outages.
A recent NOAA NHC blog details size differences in 2 major hurricanes:
Why Tropical Cyclone Size Matters: A Comparison of Hurricanes Charley (2004) & Ian (2022)
Depiction of a hurricane passing 50 miles off the coast showing wind radii of 25 and 50 miles.
Hurricane Winds Over Land
Tropical cyclone winds over land are reduced due to land friction by 20% to 50%, however, gustiness will increase from about 10% over water to 20-30% over land. For example, a wind of 80 mph over the ocean would be reduced to about 64 mph over the immediate coastal beaches and to 40-50 mph farther inland. Wind gusts, however, still could reach 75-80 mph along the beaches and 55-65 mph farther inland.
Peak winds over land often are significantly less than the “max winds” reported in a hurricane, especially when the center passes to the east of our area. Even storms passing to the west, like Hurricane Gladys in 1968, will have winds reduced over land. The key issue is whether the center passes east or west of Tampa Bay and how far-out hurricane-force winds extend at that time.
Some examples of hurricanes passing near Tampa
1921 Hurricane nearing Tampa Bay
The October 25, 1921 Tampa Bay hurricane had a peak wind of 125 mph at landfall near Tarpon Springs, just 25 miles northwest of Tampa. In Tampa, however, a peak wind of 68 mph with a gust to 75 mph recorded atop a tall building in downtown Tampa. The adjusted surface peak wind was later estimated to have been 56 mph. Most of the damage done by this storm in Tampa and St. Petersburg was due to the storm surge. The 10.5 foot storm surge in Tampa Bay was the highest since the Great Gale of 1848.
The center of the 1935 Labor Day Hurricane that decimated portions of the Florida Keys, later passed 45 miles west of Tampa with max winds of 120 mph, while Tampa recorded a peak 5 minute wind of 75 mph with a peak gust of 84 mph.
In October of 1944, a hurricane with max winds of about 95 mph passed just 15 miles southeast of downtown Tampa. The maximum sustained wind reported at Tampa was 66 mph.
In September of 1960, Hurricane Donna passed about 38 miles east of downtown Tampa with max winds about 92 mph. The highest sustained wind reported at Tampa was 62 mph with a gust to 75 mph.
In October 1968, Hurricane Gladys passed about 40 miles northwest of Tampa with max winds of 100 mph, in Tampa the max wind was 37 mph.
More recently, Hurricane Charley passed about 45 miles southeast of Tampa with max winds of 115 mph while the highest wind reported at Tampa was 23 mph with a gust to 30 mph.
Forecasting Hurricane Tracks
The National Hurricane Center’s average track forecast error has improved significantly over time, however, even today the average error just 48 hours out is about 50 nm (58 statute miles) which is close to the average extent of hurricane force winds for major hurricanes. This, unfortunately, makes it difficult to predict where the major impact will occur.
NOAA NHC Track Forecast Error over Time
Storm Surge
In most cases, it is the storm surge that does most of the damage in a hurricane. Water (due to flooding by storm surge or heavy rainfall) is the number one killer during a hurricane or tropical storm in the U.S., accounting for nearly 90% of all tropical cyclone deaths. If you are in an evacuation zone, it is imperative to monitor local evacuation zone messages as a storm approaches.
Tampa Bay Evacuation Zones
Fred Pickhardt
Meteorologist
Ocean Weather Services
