Hurricane Charley:  The Little Storm That Snuck Up On Florida

Foreword

And now we have come full circle since the beginning of Meteo 241.  My first e-portfolio project was to analyze a portion of a hurricane using the concepts in the first two lessons.  We are now at the end of the lessons, with 10 under our belts, and I've chosen to revisit Charley and apply Lessons 7-10 to the entire storm.    I chose Hurricane Charley (August 2004) because I was intrigued by how quickly the storm intensified from a Category 2 to a Category 4 storm in just a few hours.  This strengthening occurred after it left Cuba and was in the Gulf of Mexico headed for the western coast of Florida. 

In the first assignment, I focused on Charley as a Tropical Storm in the Caribbean before it made landfall in Cuba.  Now I want to focus on Charley in the Gulf of Mexico and its overnight strengthening which seemed to have caught so many, professional and layman, by surprise.  However, I will also delve briefly into some of its developmental pieces, such as its beginnings and some of the factors it encountered along its path to hurricane status.  In the end, you will see that Charley should not have been a surprise, as the National Hurricane Center / Tropical Prediction Center was predicting potential strengthening all along. 

First, some background on the storm.  Hurricane Charley was the first of the four intense hurricanes to strike the coast of Florida in the summer of 2004.  Charley was small in stature, but strengthened and accelerated prior to each landfall (another point that interested me).  Charley formed out of a tropical wave off the western coast of Africa on August 4, and made it to Barbados before being named as a Tropical Depression on August 9, when the storm moved into the southeastern Caribbean Sea.  Charley was named a Tropical Storm on August 10, and became a Hurricane on August 11th as it approached Jamaica.  Charley passed Jamaica and the Cayman Islands and was headed for Cuba on August 12.  It made landfall in Cuba on August 13 at 12:30 pm EDT as a Category 2.

Hurricane Charley left western Cuba as a Category 2 hurricane in the wee hours of August 13, and headed into the Gulf of Mexico toward Florida, right behind Hurricane Bonnie.  But in the short span of water between Cuba and the western Florida coastline, Charley spun itself into a fury, climbing two categories in roughly 3 hours (from a Category 2 to Category 4).  It remains a mystery to meteorologists how some storms tap into this rapid intensification cycle while others do not.  However, we have some good theories, and some solid scientific knowledge of storm structure and cycle dynamics.  More on these later.

Hurricane Charley made landfall five times during its lifetime. 

¨                  1st Landfall        13Aug              0430 UTC         105 kts/120 mph           Playa del Cajio, Cuba

¨                  2nd Landfall       13Aug             1200 UTC           95 kts/109 mph            Dry Tortugas Islands

¨                  3rd Landfall       13Aug              1945 UTC         130 kts/149 mph           Cayo Costa, FL

¨                  4th Landfall       14Aug              1400 UTC           70 kts/80 mph             Cape Romain, SC

¨                  5th Landfall       14Aug              1600 UTC           65 kts/74 mph             N. Myrtle Beach, SC

Beginnings

Charley began as a convective cloud cluster within an easterly wave moving off the African coast accompanied by an easterly jet (MLAEZ or mid-level African easterly jet) on August 4, 2004.  This in itself is not unusual, and in fact is a very common occurrence during the tropical season.  It's convection and low-level vorticity (cyclonic turning) became better organized by August 7, at which time the banding (spiral rain bands) became more defined.  On August 9, Charley was named a Tropical Depression and was located about 100 nm south-southeast of Barbados.  Later that night, Charley moved into the Caribbean, and the next day, August 10, was deemed a Tropical Storm.  The 5:00 am EDT August 10 Discussion #4 from the NHC website states that the outflow was excellent, the outer bands of deep convection were increasing, and the environment ahead was favorable with weak vertical shear and increasingly warm SSTs (sea surface temperatures).  The steering for the storm was provided by a subtropical ridge north of the Greater Antilles.  At that point, the models were calling for Charley to become a hurricane within 2-3 days.

Charley remained in a swift easterly steering current south of a deep-layer high, though this was forecast to weaken due to a large mid-tropospheric trough over the eastern U.S.  In looking through these discussions and the report, I kept searching for a reference to a TUTT (Tropical Upper-Tropospheric Trough), but found none.  Reference is continually made to the mid-tropospheric trough, though.  They do keep indicating that the upper-level outflow is strong through most of the storm's history.  In the August 10 11:00 pm EDT Discussion #7, Charley was forecast to become a Category 2 hurricane over the Gulf, where the SSTs were quite warm and the vertical wind shear weak.  Charley became a hurricane as it approached Jamaica on August 11, having continually strengthened as it moved through the Caribbean.  It did reach its Category 2 status, but much earlier than anticipated - on August 12 Charley was about 15 nm northeast of Grand Cayman Island.

I need to stop here and note that part of this assignment was to take a project we'd already done and elaborate on it, using concepts learned in Lessons 7-10.  My first e-portfolio project was to document a piece of Hurricane Charley, and I chose the time period prior to landfall on Cuba.  Attached is the Cuba Piece, with analysis intact from the first project.

Florida Surprise

On August 13 Charley strengthened before landfall on western Cuba.  Evidence suggested an eyewall contraction took place at this time, which is a sign of strengthening.  Now, the term 'eyewall replacement cycle' is not mentioned in either the Tropical Cyclone Report or the Discussion Archives, but I saw the slight weakening over the lower Straits of Florida after it emerged from the coast of Cuba as an indication of this scenario.  However, I've been looking for evidence to back this up, and have found none.  However, there is much reference in the Discussions to the eyewall contraction and small eye feature.  To back this up, the report goes on to say that after Charley passed over the Dry Tortugas, it "began to intensify rapidly, and the eye shrank considerably in the 12 hours before landfall in Florida" (page 2).  Charley's rapid intensification from the point of emergence from Cuba to three hours later saw it go from a Category 2 to a Category 4 hurricane.  It should be noted here that the intensification and strengthening were not the surprise, but how quickly it occurred was a surprise.  This is an important point, because the discussions all indicated strengthening forecast, and the report states that the intensity forecasts called for Charley to strengthen from a Category 2 to a Category 3 by landfall in Florida, but a special advisory was issued about 1800 UTC on August 13 indicating it had strengthened to a Category 4.  And on August 11, the 11 am EDT Discussion #9 stated that Charley had the potential to be a stronger hurricane over the Gulf than indicated in their stats.   

As Charley approached the western coast of Florida, its pressure fell 5.02 mb per hour before landfall.  This rapid fall in pressure is also an indication of the the storm strengthening again with the eyewall contraction.  Charley was a strong Category 4 hurricane when it made landfall at Punta Gorda, Florida, on August 14, with winds of 130 knots, or 149 mph.  Since the storm strengthened overnight just prior to landfall, the coastal residents were prepared for a Category 2 storm, with potential for a Category 3.  The strong mid- to upper-level trough over the central Gulf of Mexico helped to accelerate Charley north and north-northeastward toward Florida by the evening prior to landfall (August 13), the waters were warm (high SSTs) and the vertical shear was low.  The 11:00 am EDT August 12 Discussion #13  stated that there was "a distinct possibility that Charley could be near major hurricane strength when it makes landfall along the Florida west coast."  All of the August 12 advisories indicate potential strengthening, with very little weakening due to friction from crossing the Cuban peninsula.  The 11:00 pm EDT August 12 Discussion #15 states that "there is still potential for rapid intensifying over the southeastern Gulf of Mexico" due to the well-defined eye, warm waters and excellent outflow.  A dry slot wrapping around the inner core was noted as a potential negative in storm development.  The August 13 advisories keep indicating the probability of strengthening before landfall in Florida.  The satellite image at the beginning of this document shows the compact eye and well-formed rain bands and outflow of Hurricane Charley about an hour prior to landfall on August 13.

In the 11:00 am EDT August 13 Discussion #17, the NHC notes that the pressure dropped 5 mb in 2 hours, "suggesting that there could be some additional strengthening during the next several hours before landfall on the Florida west coast."  By 2:00 pm EDT August 13, a Special Discussion #18 was issued to warn of increased winds (to 125 knots or 143 mph) and a shift in the forecast track to the east, "which shifts the greatest risk to the area of Charlotte Harbor, Florida."  By the 5:00 pm EDT August 13 Discussion #19, the center of Charley had moved inland near Charlotte Harbor, Florida, with surface winds at about 125 knots and pressure at 941 mb.  The eye had shrunk to 5 miles in diameter, indicating a tightly spinning eyewall.  An unofficial gust was reported near Punta Gorda, Florida, of 127 mph, or 110 knots.  They thought the intensity would still be near hurricane force when the center moved over the Atlantic.

The wind core of Charley remained tight and strong, though the coverage and intensity of convection decreased, over land.  It became embedded in a deep layer of southwesterlies on the east side of an unseasonably strong trough, and was about to move over cooler waters than the Gulf with increased vertical wind shear and increasing proximity to a frontal zone.  Merging with the frontal zone would make it extratropical, which it did between the 5:00 pm EDT August 15 Discussion #25 and the 11:00 am EDT August 16 Discussion #26 advisories (meaning that it took awhile for Charley to weaken, even over land in North Carolina. 

Summary

I'd like to wrap up the story of Hurricane Charley by noting that the people on the western Florida coast were preparing for a Category 2 hurricane, and were caught somewhat unpleasantly by surprise at its rapid strengthening just before landfall.  The difference between a Category 2 and a Category 4 hurricane is substantial in damage, and the extent of damage from Charley was evidence of this surprise (you can find Casualty and Damage Statistics for Charley on pages 4-5 of the Tropical Cyclone Report ).  Charley's damage made it the 2nd costliest hurricane since recordkeeping began in the mid-1800s, with Hurricane Andrew in 1992 being the costliest  - however this record was broken when Katrina became the costliest, bringing Andrew down to second and Charley down to third.  The 2005 hurricane season broke a number of records, even those broken by the 2004 season, and these have not been posted on the official lists yet.  Katrina, Rita and Wilma have taken over numerous records, with Wilma now holding the #1 record for lowest pressure at 882 mb, Rita now at #4 with 897 mb, and Katrina at #6 with 902 mb. 

Charley was a very destructive storm, with rainfall totals of around 5 inches reported in Cuba and from 5-8 inches in Florida.  There were 9 tornadoes reported across Florida, a storm surge of anywhere from 4-7 feet depending on location, and 10 deaths in the U.S. directly attributed to the hurricane, 4 in Cuba and 1 in Jamaica, making a total of 15.  In addition to damage from hurricane force winds, tornadoes and storm surge, North Captiva Island experienced a 450 mile wide breach through its center.  The illustrations below show the difference in North Captiva Island before and after Hurricane Charley.

Sanibel Island was also heavily impacted by Hurricane Charley's category 4 strength at landfall.  This USGS website offers some comparison photos of before and after damage:  http://coastal.er.usgs.gov/hurricanes/charley/site-index.php?storm_id=7&site_id=17.

According to the Forecast and Warning Critique in the Tropical Cyclone Report (page 5), there should have been no surprises as the official intensity forecasts, the special advisory on Category 4 status, and the issuance of hurricane watches and warnings in a timely manner accounted for all necessary preparations.  Also, the report states that "the hurricane made landfall within the area covered by the hurricane watch and warning."  Indeed, the "mean official track forecasts for Charley were better than the 10-yr average through 72 hours, meaning the forecast errors for the cone of potential path were less than normal. 

Below is a radar image of Hurricane Charley at landfall.  The rain bands are very well defined.  Charley may have been small, but it was a very compact and powerful storm.  Keep in mind that this was about the time North Captiva and Sanibel Islands were being breached and battered.

Afterward
Now it's time to reflect on the concepts learned and the experiences gained in this class.  For one, this has been one of the most enriching experiences I've ever had.  My goal upon beginning the certificate program was to be able to understand the terms and concepts used in official storm reports, storm chaser logs, and by the meteorologists on the local weather and The Weather Channel.  I wanted to be able to look at the various maps and be able to read and interpret them in order to better understand what was happening outside based on those data.  I found the science extremely challenging, but am more surprised by how challenging the writing part has turned out to be.  I fancied myself a good writer up until now - I guess I'm just having trouble merging the left brain writing with the right brain science. 

Another thing I learned that was unexpected was how to set up and create web pages.  I've learned to use FrontPage and Ultimate Paint, which turned out to be fun.  Not to mention useful for other endeavors that may come along later. 

But that just skims the surface.  I've been watching The Weather Channel for awhile, and now I understand what they're talking about and how it works, as well as when they say something that isn't quite right.  Or at least I know enough to be alerted to question.  It's opened up a whole world that I'd always been curious about but could never set foot in.  Also, people use me as the weather resource.  For instance, I work at a university, and they are currently under a Provost search.  The committee is coming in from various places to go through materials, and the search firm was to fly in yesterday.  We're in Missouri, but other people from around the country think of Kansas City as Kansas.  There were blizzard conditions in western and central Kansas night before last, causing highways to be closed down and stranding people who were traveling.  This caused an uproar with people traveling in for the search.  The coordinator of the event came and asked me what was going on that was of such concern to these travelers, as they had expressed surprise that we weren't shut down for snow.  I am proud to say that I was able to tell her what had happened and why, because she also asked how it might affect us here.  That felt great!

On another note, this class was extremely timely in that we have had a record season for tropical weather, unlike any other, even the Florida Quad from 2004.  I don't think we could have asked for any better class laboratory than Mother Nature provided for us this semester.  And it's still developing - we've just had the 26th named storm and the 5th named storm in the Greek alphabet - Tropical Storm Epsilon, named one day before the official hurricane season ends November 30th.  first of all, we've never gone into the Greek alphabet before.  Second of all, we've never had this many named storms in a season before.  I think we're all in awe of this, even the instructors.

Looking back at Charley and knowing that it was one of the record breakers at the beginning of a record breaking stretch of record breakers (bad English done on purpose there) has been interesting in that I was able to see the patterns that were emerging (the eyewall contraction and sudden strengthening overnight being of keen interest to me).  It was also interesting to compare the larger storms with the smaller storms, and note that size had nothing to do with strength or damage capability.  It makes them all the more fascinating to know that each one is individual and will most likely be completely different from the others, yet with similarities enough to be able to see the patterns I just mentioned.

I don't know how to close this reflection.  I don't want this class to end, but am looking forward a great deal to the next one next semester.  I didn't know if I could do this, but find that it was more than worth the money and the time.  Whatever shall I do when all the classes are completed ...

Debbie Jarvis-Ferguson

Meteo 241

Penn State University

December 9, 2005