Ian Update: Near Worst Case Scenario

September 26, 2022

Jeff Masters and Bob Henson for Yale Climate Connections:

Rapidly strengthening on Monday, Hurricane Ian is on track to slam into western Cuba early Tuesday morning, most likely as a major hurricane, before taking a complex and potentially devastating course along the Florida Gulf Coast. Whether or not Ian comes ashore on Florida’s west coast, the Tampa Bay area – which has not seen a major hurricane in more than a century – is facing one of its most dangerous hurricane threats in decades. People along Florida’s west coast need to take Ian with the utmost seriousness and consult local authorities for evacuation orders that could be extended quickly based on Ian’s progress.

At 2 p.m. EDT Monday, category 1 Ian was 120 miles west-northwest of Grand Cayman, with top winds of 85 mph, headed north-northwest at 13 mph. Ian was bringing heavy rain showers to Jamaica, the Cayman Islands, and much of Cuba, as seen on Cayman Islands radar. The eyewall of Ian missed the Cayman Islands, and the peak winds observed at Grand Cayman on Monday morning were sustained at 28 mph, gusting to 44 mph.

Satellite imagery early Monday afternoon showed the symmetry, organization, and intensity of the storm’s heavy thunderstorms steadily increasing, and Ian had the look of a storm well on its way to becoming a major hurricane. Rainbands were already moving into South Florida on Monday afternoon.

Track forecast for Ian

Ian’s track will be fairly straightforward through Tuesday. The storm will move over or near the western end of Cuba early Tuesday, predicted by NHC to be a major hurricane at that point (see below). Havana will be on the stronger right-hand side of Ian: the city is very likely to experience tropical-storm-force sustained winds of 40 to 60 mph, and hurricane-strength winds are possible if Ian shifts just to the right or is larger than expected by Tuesday. Major impacts can be expected across far western Cuba, including 6 to 10 inches of rain along Ian’s path and storm-surge inundation of 9 to 14 feet on Cuba’s southwest coast near and just east of Ian’s track.

Despite this general model agreement, small differences in Ian’s track angle could have major implications for impacts in Florida.

West versus east: Through Sunday night, the GFS model continued to track Ian on the western side of guidance, taking Ian toward the Florida Panhandle, whereas the European and UKMET (British) models have been consistently further east, bringing Ian across or very near the Tampa Bay area (see Figure 1 above). Importantly, the 12Z Monday run of the GFS model shifted sharply eastward, much more in line with the ECMWF and UKMET forecasts, which both bring Ian into the Tampa Bay region.

Timing: The geography of Florida’s Gulf coastline means that a more westward track would keep Ian over the Gulf longer, thus increasing the amount of time Ian might be affected by the high wind shear and dry air expected to arrive around midweek (see below). In this case, a more northerly landfall could be much weaker in terms of peak winds, and it would occur later – perhaps as late as Friday on the Panhandle coast, versus a potential landfall in Tampa as soon as Wednesday if the eastern track proves more accurate.

A pause near Tampa? The trough across the eastern U.S. will have moved far enough east by Wednesday that it will exert less of a tug on Ian’s motion. The major models agree on a potentially crucial slowdown in Ian’s movement for about 24 hours, mainly from Wednesday into Thursday. Around Thursday, Ian should resume a somewhat faster northward motion.


One Response to “Ian Update: Near Worst Case Scenario”

  1. rhymeswithgoalie Says:

    This 2014 video is a run-through of the “Hurricane Phoenix” scenario for Tampa:

    Similarly, Katrina came pretty close to the “Hurricane Pam” scenario for New Orleans.

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