Florida Hurricanes: Is A Warming Climate Having An Impact?

Florida Hurricanes: Is A Warming Climate Having An Impact?

• After a period of relative calm – 2006-2016 – BANG! • This is a story of – Super warm sea water – Sahara Dust – Explosive Development Cycles – Record Raining Hurricanes – Pinhole EYE Developments And the role of a warming climate4 on all of the above

Accumulated Cyclone Energy (ACE) • A measure of a named storm’s potential for wind and storm surge destruction defined as the sum of the square of a named storm’s maximum wind speed for each 6-hour period of its existence.

• The 1950-2000 average value of this parameter is 96 for the Atlantic basin.

► Storm must be developing over warm water of at least 80 degrees. ► Ocean water must be warm enough to a depth of at least 200 feet. ► Very little wind shear in the area. ► Rapid cooling of air temperature with height forcing condensation.

2018 Hurricane Season Review

Gulf Loop Current

A Slightly Above Normal Season • 15 Named Storms is above the average of 12 • 2 Major Hurricanes: Florence/Michael – Normal and 8 Hurricanes overall • Both Hit the US coastline • Florence was a Cat 4 and hit the Carolina’s as a Cat 2 and a rainfall record breaker • Michael was a upper end Cat 4 and a wind and storm surge catastrophe

Summary of 2019 Hurricane Season

Normal Strikes By State

Notable Facts About 2018 • For the first time since 1997, no hurricanes in Tropical Atlantic • First two weeks of September were BIG with 5 named storms tying a record • During 17/18 seasons for the first time ever, THREE Cat 4 storms that hit the US. Harvey, Irma & Michael

2018 - A Tale Of Two Seasons • 2018 May though August was Quiet with a number of smallish storms • Lots of Sahara Dust and cool sea surface temperatures in the Atlantic

• Significant Wind Shear in the Gulf but a very warm Loop Current obvious early in season

Sahara Dust Inhibits Hurricane Development

2017 – 2018 Highlights • Harvey & Florence – Record Rain Makers • Harvey, Irma, Michael - Three CAT 4’s strike US coast for first time in a 2 yr. period • September was the Hurricane Season

2017/18 Highlights - continued • Explosive development (ED) cycles – Harvey, Irma, Maria, Jose, Florence and Michael • Pinhole Eyes in all 5 storms & others that stayed offshore

Sarasota Magazine Quotes • “Sarasota is more vulnerable to storms—like Wilma or Charley—that form in the Caribbean and enter the Gulf of Mexico, usually early or late in hurricane season.

• (The most perilous time for us, Bunting says, is the first two weeks of October.)

• But even those storms rarely hit our stretch of the west coast. Because of the shape of Florida’s land mass and atmospheric factors related to the rotation of the earth, they tend instead to make landfall to the south, often around Naples, and travel east across Florida, or to curve north and hit the northern Gulf Coast.”

Sarasota Magazine -continued • Does this mean we can breathe easy? Hardly, says Bunting, who confesses, “I couldn’t sleep” during the days that Irma threatened our coast. “All it takes is one,” he says. “Only one.””

• Interview May 2018 for July 2018 Cover Story

First Major Hurricane • Florence – Stuck in Sahara dust early on Aug 31 – Sept 2 – Rapid intensification to Cat 4 – Stuck NC and SC as Cat 2

– Stalled like Harvey and dumped record rainfall on both states. 36 in vs. 24 in NC. 24 in vs. 18 in SC!

Stalling Hurricanes • Weaker Jet Streams result from a rapidly warming arctic and a more slowly warming equatorial area.

• Temperature gradients from N to S drive Jet Stream intensity.

• Weakening gradients due to warming climate means storms can linker dumping copious rain.

Florence

Path - Florence

Two Majors Two Hits • Michael – A September to remember storm – First Cat 4 Storm ever in the FL Panhandle – 4th highest sustained wind in US history - 155 mph – 3rd lowest atmospheric pressure in US history – 919 mb vs. normal 1013 mb – Lowest ever measured pressure was 905 mb in a cyclone (hurricane) on April 22, 1989 in Australia

Path - Michael

Michael’s Radar Landfall

Michael’s Hot Loop SST

What Makes Pinhole Eyes • Hot water 200 feet deep (82F +) • Weak vertical wind shear • Low dust levels All present In both Septembers to remember!

Florence

Irma Pinhole

Record SST’s For Irma

Michael

Two Trends Impacted By Warming?

• More Pinhole Eyes – Tornado like concentrated damage & Storm Surges (IRMA & Michael)

• More slow moving storms – Record rains and flooding (Harvey & Florence)

Florence vs. Michael • MICHAEL - https://www.nhc.noaa.gov/

Florence vs. Michael • FLORENCE - https://www.nhc.noaa.gov/

Let’s Look @ Losses • Irma (wind & surge) damage to Fl and Harvey (mostly flood) damage to Tx estimated at $150 - $200B • Florence (flood) damage to Carolina’s estimated at $20B and the loss of 3.4 million poultry birds and 27,000 hogs • Michael (wind & surge) damage to Fl & Ga at around $10B

Barbuda

Mexico Beach - Before

Mexico Beach - After

Houston I10

Florence

Before

After

Climate Warming & Hurricanes?

• Warmer Sea Temperatures trigger explosive development (ED) – Very fast development cycles last 2 Septembers – Pinhole Eyes mean large tornado like damage paths & huge storm surge to the right of a land-falling Eye • Weaker jet streams mean stalling storms with big rain/floods

Climate Warming & Hurricanes?

• While the number of Hurricanes may not be changing their characteristics may be • Big Damage and Losses!

• Portend serious evacuation issues when ED occurs near heavily populated coastlines Not Convinced? – 2018 had the 3highest ACE in Northern Hemisphere and 10 CAT 5 storms the 2nd highest ever!

What About 2019?

It’s Early But So Far A Normal Atlantic Hurricane Season Is Indicated

2019 ACE Very Early Forecast • • • • • •

80 ACE – 8-11 named storms, 3-5 hurricanes, 1-2 major hurricanes Not too unlike 2018 AS ALWAYS: “IT JUST TAKES ONE”

That’s It! • Special thanks to Dr. Phil Klotsbach – CSU Hurricane Forecaster