Monday, December 11, 2017
Tampa Bay Weather

Hurricane Irma: Best and worst case scenarios for Tampa Bay

Every weather update brings more bad news.

It looks more and more likely that Hurricane Irma will hit Florida, but exactly where is hard to say. Some models show landfall around Tampa Bay while others call for a hit closer to Miami.

LIVE BLOG: The latest updates on Hurricane Irma

What are the best and worst scenarios for the west coast?

CLICK HERE FOR AN UPDATED VERSION OF THIS STORY: Best and Worst case scenarios for Tampa Bay with Irma nearing Florida

There is a slight chance, maybe about 10 percent, that the hurricane — already a Category 5 storm — curves east and back out to the Atlantic, said Jeff Masters, co-founder Weather Underground. That's the best option.

CATEGORY 5 HURRICANES: Eight things you need to know

There's a roughly 20 percent chance that the storm hits Cuba or Hispaniola, Masters said, weakening before it heads toward the mainland United States.

"Cuba has destroyed a number of intense, major hurricanes," Masters said, including Hurricanes Dennis in 2005 and Ike in 2008. That would also be better for Florida.

But the notorious spaghetti plots show a grimmer picture, the variegated lines essentially blocking out the entire peninsula in forecast maps.

"The spaghetti is centered right over the center of Florida and there's a lot of spaghetti to both sides," Masters said.

HURRICANE GUIDE: Emergency information, tracking map and storm resources

The cone of uncertainty (where a storm could make direct landfall) covers the entire southern third of the state.

The message, then, is familiar: Don't panic, but prepare.

In Tampa Bay, the biggest threat from a hurricane is storm surge. A potentially devastating track for Irma would take it up the state's west coast, just offshore, said 10Weather WTSP meteorologist Bobby Deskins. Some models show Irma blowing over Key West with 135 mph winds before moving north as a Category 3 or 4 storm. That would send water rushing over barrier islands and surging into Tampa Bay.

"That's kind of the worst case scenario for us is a west coast brush," Deskins said.

Irma is unique because it has been a powerful storm for a while, and it's getting bigger. On Tuesday at 2 p.m., the National Hurricane Center announced the storm was already the strongest hurricane ever recorded so far east in the Atlantic Ocean. Winds were up to 185 mph.

"The problem with hurricanes is as they get older, as they're around longer, they grow," said Colorado State University research scientist and hurricane forecaster Phil Klotzbach.

Irma has experienced several eyewall replacement cycles — a common process for major hurricanes that widens the windfield, Klotzbach said.

Satellite imagery suggests Irma has already undergone four such cycles, said Derrick Herndon, an associate researcher at the University of Wisconsin-Madison. Another storm that experienced several eyewall replacements was Hurricane Ivan in 2004, he said.

LIVE RADAR: Interactive storm track, hourly outlooks, 10-day forecasts and weather alerts

If Irma misses Cuba and Hispaniola and heads into the Straits of Florida, it would become even more massive. The storm cold undergo another eyewall replacement as it passes over that area, sucking up warm water and intensifying further, said Herndon, who works at the Cooperative Institute for Meteorological Satellite Studies.

The hurricane will likely be very different than the region's last close call, Hurricane Charley, an extremely tight but powerful cyclone that struck Punta Gorda in 2004.

"Irma could miss Tampa by 100 miles and there could still be significant impact in Tampa because the storm is very large," Herndon said.

Some models call for the hurricane to hit the southern tip of the state and spin straight north, which would bring tropical storm force winds and downpours to both the east and west coasts.

"Heavy rain is going to be an issue," Masters said. "I think regardless of what this storm does Tampa is going to get [at least] 5 to 10 inches of rain."

Based on early models, forecasters are citing Hurricane Donna, which struck Florida in 1960, as a good comparison for what Hurricane Irma could potentially do.

LOOK BACK: Hurricane Irma is being compared to Donna, which slammed Florida back in 1960

Masters, in a blog post Tuesday, wrote of how Donna churned through the Florida Keys as a Category 4 storm before hooking into the area around Naples and Fort Myers. The storm pushed into the center of the state as a Category 2 storm, continuing to wreak havoc before spitting back out into the Atlantic.

Donna showed that even cities inland should not feel safe from an approaching storm, Masters said.

"That storm was no joke," Klotzbach said.

But Floridians should also know Irma will not be a perfect duplicate of Donna, said Rick Knabb, a hurricane expert at The Weather Channel and former director of the National Hurricane Center.

"It's definitely a top-end hurricane, Category 5. It's scary," he said. But just where it hits and how strong it will be at that point remains to be seen.

"Irma will write its own story," Knabb said. "It's not going to behave like any past hurricane."

Contact Zachary T. Sampson at [email protected] or (727) 893-8804. Follow @ZackSampson.

Comments
Forecast: Warm breezes across Tampa Bay ahead of fluctuating conditions

Forecast: Warm breezes across Tampa Bay ahead of fluctuating conditions

Chilly, windy, colder, sunny, warmer, rainy.10News WTSPFeels-like temperatures around the Tampa Bay area This weekís inconsistent weather conditions will at least keep things interesting across the Tampa Bay area, even if it makes it difficult to de...
Updated: 1 hour ago
Forecast: Freeze warning for some Tampa Bay residents, but warmer weather coming

Forecast: Freeze warning for some Tampa Bay residents, but warmer weather coming

Portions of the Tampa Bay area under a freeze warning as this weekendís cold blast extends into the start of the workweek.10News WTSPFeels-like temperatures around the Tampa Bay area That wintry feel, however, is coming into an end as conditions beg...
Published: 12/11/17
Itís so cold outside that it snowed in Florida

Itís so cold outside that it snowed in Florida

Usually the words "snow" and "Florida" donít go together.But a cold front over the weekend has proved that rule wrong for shivering Floridians, bringing in a dusting of snow across the western Panhandle late Saturday night into Sunday morning.As temp...
Published: 12/10/17
Forecast: Parts of Tampa Bay under freeze watch as cold temperatures linger

Forecast: Parts of Tampa Bay under freeze watch as cold temperatures linger

Bundle up, Tampa Bay: Itís a chilly Sunday. 10News WTSPThe latest Tampa Bay-area radar 10News WTSPFeels-like temperatures around the Tampa Bay area The skies are clear and thereís little-to-no chance of ra...
Published: 12/10/17

Rotary Club cancels Saturday boat parade because of weather

ST. PETERSBURG ó A third boat parade was canceled Saturday because of this weekendís bad weather.The Rotary Club of St. Petersburg will not host its lighted boat parade on Saturday evening because of a small craft advisory. The National Weather Servi...
Published: 12/09/17
Forecast: Tampa Bay begins weekend cold snap

Forecast: Tampa Bay begins weekend cold snap

After heavy showers covered much of Tampa Bay Friday night, Saturday started out drier ó and colder.There was still some mist in the air that was expected to continue in the mid-day, said WTSP 10Weather meteorologist Bobby Deskins. 10...
Published: 12/09/17
The weather outside is frightful. Well, wet and cold anyway.

The weather outside is frightful. Well, wet and cold anyway.

Prepare yourselves Tampa Bay: Itís finally time for sweater weather.But you might need your rain jacket and umbrella, too.The weekend started Friday night with severe rain and wind gusts ó even a slight risk of a tornado ó that canceled some weekend ...
Published: 12/09/17
Southern snowfall isnít deep, but many fear overnight freeze

Southern snowfall isnít deep, but many fear overnight freeze

ATLANTA ó Snowfall blanketed parts of the Deep South on Friday, delighting schoolchildren with an unexpected holiday but also reviving panicky memories for many adults of past storms that trapped commuters on interstates for hours. Businesses closed ...
Published: 12/08/17
Wild weather expected, 2 boat parades canceled

Wild weather expected, 2 boat parades canceled

Boat parades that were planned tonight in South Pasadena and St. Pete Beach have been canceled because of weather fears.Organizers said they will not be rescheduled. Heavy rain is expected to approach the gulf coast near sunset Friday ahead of a stro...
Published: 12/08/17
So, is it going to snow in Florida this weekend?

So, is it going to snow in Florida this weekend?

Letís talk snow. A day after parts of Texas ó which rarely see flurries ó were dusted with snow, Floridians were starting to ask, "So, could we see some flakes?" Well, to be blunt: Probably not. But there is a chance if you live in the Panhandle.The ...
Published: 12/08/17