Tropical Storm Eta was bringing torrential rains, tropical storm-force winds, and a storm surge in excess of two feet to the west coast of Florida on Wednesday afternoon as it headed for an expected early Thursday morning landfall north of Tampa. Early Wednesday morning, Eta became the latest hurricane in the Gulf of Mexico in any calendar year since Hurricane Kate on November 19-21, 1985.
At 1 p.m. EST Wednesday, Eta was a tropical storm with 70 mph winds and a central pressure of 990 mb, moving north-northeast at 10 mph. According to data from NOAA, Eta brought a storm surge of 2.86 feet to Naples, Florida, during the Wednesday late morning high tide cycle, causing minor coastal flooding. Winds at Naples were as high as 30 mph, gusting to 55 mph, late Wednesday morning. Sarasota recorded sustained winds of 35 mph, gusting to 51 mph, at 11 a.m. EST Wednesday. Radar-estimated rainfall amounts over western Florida from Eta since November 8 were generally 2-4 inches, as of noon EST Wednesday.
Satellite and radar images showed that Eta peaked in organization early on Wednesday morning, with a well-defined eye surrounded by an intense ring of eyewall thunderstorms. However, dry air from the west, driven into the core of the storm by moderate wind shear of 15-20 knots, destroyed Eta’s eyewall late Wednesday morning, leaving the surface circulation center exposed to view and all of Eta’s heavy thunderstorms confined to the east side of the center.
Forecast for Eta
The models are in strong agreement that Eta will make landfall north of Tampa and south of Cedar Key, Florida, on Thursday morning, and then continue to the northeast across Florida, emerging over the Atlantic Ocean on Thursday evening near the Florida/Georgia border.
Dry air should is expected to interfere with Eta’s development until landfall on Thursday morning. Eta will be moving over progressively cooler waters as it approaches the coast of Florida, which will also favor weakening. The official National Hurricane Center forecast calls for Eta to be a tropical storm with 65 mph winds near the time of landfall, but most of the intensity models predict that Eta will be weaker than that.
The primary damaging threat from Eta will be storm surge, since Tampa Bay acts to amplify storm surge during strong, persistent onshore winds. Eta could bring 3-5 feet of inundation to the bay during the Wednesday night high tide cycle, just before midnight. A three-foot storm surge at high tide would be a top-five high water event for St. Petersburg, and the highest in 24 years. Water level records there go back to 1947.
The difference between low tide and high tide is 1.5 to 2 feet, so coastal flooding will be considerably lower near low tide. Heavy rains of 2-4 inches, with isolated amounts of 6 inches, will cause additional problems for western Florida, and tropical storm-force winds will lead to considerable tree damage and power outages.
Theta poses little threat to land
Tropical Storm Theta, the record-breaking 29th named storm of the 2020 Atlantic hurricane season, was slowly weakening on Wednesday as it moved over the waters of the northeastern Atlantic. At 10 a.m. EST Wednesday, Theta was located about 670 miles southwest of the Azores Islands, headed east-northeast at about 10 mph. Theta had top sustained winds of 60 mph, and satellite images showed the storm struggling with high wind shear, which had exposed its circulation center to view.
Theta will move east to east-northeast through the end of the week, taking the storm between the Azores Islands and Canary Islands. The only land area in Theta’s five-day cone of uncertainty is Portugal’s Madeira Island, which could experience tropical storm conditions on Sunday. High wind shear and cold waters are expected to weaken Theta to a post-tropical cyclone with 40 mph winds by Sunday.
98L likely to become Tropical Storm Iota in the Caribbean this weekend
A tropical wave in the eastern Caribbean, designated 98L by NHC, was bringing heavy rains to the Virgin Islands, Puerto Rico, and the Dominican Republic on Wednesday. A flash flood watch was posted for eastern Puerto Rico and the Virgin Islands, where 2-4 inches of rain was predicted. Satellite imagery showed that 98L’s heavy thunderstorm activity was disorganized, but the cloud pattern at mid-levels was beginning to show some spin, and the system appeared poised to take advantage of favorable conditions for development: moderate wind shear of 10-20 knots, warm SSTs of 29 degrees Celsius (84°F), and a moist atmosphere.
The top three models for predicting tropical cyclone genesis were giving 98L strong support for development by this weekend, when the wave will likely be in the central or southwestern Caribbean, between Jamaica and Nicaragua. The wave is predicted to move west-southwestward and then westward at about 5-10 mph under the steering influence of a ridge of high pressure to its north, resulting in a potential threat to Jamaica, the Cayman Islands, and Central America this weekend. Conditions for development will be favorable through Monday, with the SHIPS model predicting light to moderate wind shear of 5-15 knots, warm SSTs of 29-29.5 degrees Celsius (84-85°F), and a moist atmosphere with a mid-level relative humidity of 65-70%.
These conditions are very similar to what Hurricane Eta experienced in its formative stages in the Caribbean in late October, and 98L is a threat to intensify into a hurricane that will affect the same areas of the Caribbean impacted by Hurricane Eta. In particular, Nicaragua and Honduras, which were devastated by Hurricane Eta, appear at great risk of receiving heavy rains from 98L beginning on Monday. The 0Z, 6Z, and 12Z Wednesday runs of the GFS model, which showed 98L affecting Nicaragua as a hurricane on Tuesday, are quite concerning.
In a 1 p.m. EST Wednesday tropical weather outlook, NHC gave 98L two-day and five-day odds of development of 30% and 80%, respectively. The next name on the Atlantic list of storms is Iota, the ninth letter in the Greek alphabet.
Posted on November 11, 2020(1:55pm EST).