The odds of a hurricane spoiling the Republican National Convention in Tampa

By: Dr. Jeff Masters , 4:48 PM GMT on August 14, 2012

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On September 25, 1848, the Great Gale of 1848, the most violent hurricane in Tampa's history, roared ashore as a Category 3 or 4 hurricane with 115 - 135 mph winds. Major R. D. S. Wade weathered the storm in Fort Brooke, in what is now downtown Tampa. Here is what he wrote this to his commanding officer in Washington D.C.: "The waters rose to an unprecedented height, and the waves swept away the wharves and all the buildings that were near the Bay or river." A 15-foot storm surge was observed at Fort Brooke, and the peninsula where St. Petersburg lies in Pinellas County was inundated "at the waist" and "the bays met," making St. Petersburg an island. After the hurricane, "Tampa was a scene of devastation. Magnificent old oaks were toppled by the hurricane's winds. At Fort Brooke the barracks, horse shed, and other structures were gone. The pine forest north of the garrison was filled with wreckage and debris. The hurricane's powerful surge had shifted sand all along the coast and reshaped many of the keys near Tampa Bay. Navigation routes were filled in and closed, making charts of the area produced before 1848 almost useless after the hurricane. In terms of intensity and destruction, the 1848 storm remains perhaps the greatest in Tampa's history" (Barnes, 1999.)


Figure 1. Pencil sketch of the Captains' Quarters, drawn by one of the officers stationed at Fort Brooke in 1845. Fort Brooke was one of the largest military establishments in the United States at the time. Image Credit: The Tampa Bay History Center.

Fort Brooke today
Fort Brooke is the current site of the Tampa Bay Convention Center, which hosts the Republican National Convention on August 27 - 30 this year. The convention center is in Evacuation Zone A, which is evacuated for Category 1 hurricanes. The Tampa Bay Times Forum and two major convention hotels--the Tampa Marriott Waterside and the Embassy Suites--are in Evacuation Zone B, which is evacuated for Category 2 hurricanes. In a worst-case Category 4 hurricane, the Convention Center could be immersed in 20 feet of water. Clearly, even a Category 1 hurricane would be enough to spoil the convention. So, what are the odds of a mass evacuation order being issued for Tampa Bay during the convention?


Figure 2. Predicted height above ground of the water from a worst-case Category 4 hurricane in the Tampa Bay region, as computed using NOAA's SLOSH storm surge model. The Tampa Bay convention center would go under 20 feet of water, and St. Petersburg would become an island, as occurred during the 1848 hurricane.


Figure 3. Perhaps the most spectacular hurricane image ever captured: view of Hurricane Elena on September 1, 1985, as seen from the Space Shuttle Discovery. At the time, Elena was a Category 3 hurricane with 125 mph winds, located just 80 miles offshore from Tampa Bay, Florida. The hurricane prompted the largest mass evacuation in Tampa Bay history.

Two mass evacuations in Tampa in the past 25 years
Two hurricanes have prompted mass evacuations of more than 300,000 people from the Tampa Bay area over the past 25 years. The first was Hurricane Elena of 1985, a Category 3 hurricane that stalled 80 miles offshore for two days on Labor Day weekend, bringing a 6 - 7 foot storm surge, wind gusts of 80 mph, and torrential rains. On August 13, 2004, another mass evacuation was ordered for Hurricane Charley. Thanks to a late track shift, Charley missed Tampa Bay, and instead hit well to the south in Port Charlotte as a Category 4 storm with 150 mph winds. More limited evacuations of low-lying areas and mobile homes in the 4-county Tampa Bay region were ordered for three other hurricanes in the past fifteen years--Hurricane Georges of 1998, Hurricane Frances of 2004, and Hurricane Jeanne of 2004. Other historical storms which would likely trigger mass evacuations were they occur today include:

The 1921 hurricane. One of only two major hurricanes to hit Tampa, this Category 3 storm brought a storm tide of 10.5 feet.

Hurricane Easy of 1950. The hurricane parked itself over the west coast of Florida, drenching residents with record-breaking rains, and brought a 6.5 ft storm surge to Tampa Bay.


Figure 4. Damage to Bayshore Boulevard after the 1921 Tampa Bay hurricane. The road leads to the Tampa Bay Convention Center from the south.


Figure 5. Track of the Tampa Bay Hurricane of 1921, one of only two major hurricanes ever to hit the city. This Category 3 storm with 115 mph winds brought a storm tide of 10.5 feet to Tampa Bay.


Figure 6. A near miss: just a slight deviation in the path of Hurricane Charley of 2004 would have brought the Category 4 hurricane into Tampa Bay.

Tampa Bay's vulnerability to hurricanes
Tampa Bay doesn't get hit very often by hurricanes. The last time it suffered a direct hit by any hurricane was 1946, when a Category 1 storm came up through the bay. The Tampa Bay Hurricane of October 25, 1921 was a the last major hurricane to make landfall in the Tampa Bay Region. At that time, there were 160,000 residents in the 4-county region, most of whom lived in communities on high ground. Today there are 2.75 million residents in the region, most of whom live along the coast and low-lying areas or in manufactured housing. About 1/3 of the 4-county Tampa Bay region lies within a flood plain. Over 800,000 people live in evacuation zones for a Category 1 hurricane, and 2 million people live in evacuation zones for a Category 5 hurricane, according to the 2010 Statewide Regional Evacuation Study for the Tampa Bay Region. Given that only 46% of the people in the evacuation zones for a Category 1 hurricane evacuated when Category 4 Hurricane Charley threatened the region, the potential for hundreds or thousands of people to die when the next major hurricane hits the region is high. In the long run, I expect a multi-billion dollar sea wall will be built to protect Tampa Bay from storm surges, since sea level rise will make storm surge damages increasingly problematic. A 2007 study by Tufts University titled, Florida and Climate Change, found that a 2.25 foot increase in sea level--which many sea level rise scientists expect will happen by the end of the century--would put 152,000 people in Pinellas County (where St. Petersburg is located) at risk of inundation.

The hurricane forecast for the Republican National Convention
Given that there have been two mass evacuations of Tampa during the past 25 years during the peak three-month period of hurricane season--August, September, and October--history suggests that the odds of a mass evacuation order being given during the 4-day period that the Republican National Convention is in town are probably around 0.2%. Any tropical waves which might develop into hurricanes that could hit Tampa during the convention would have to come off the coast of Africa next week. Looking at the latest 16-day forecast from the GFS, all of the tropical waves coming off of Africa next week are predicted to exit too far north to make the long crossing of the Atlantic and threaten the Gulf Coast. While something could develop in the Gulf of Mexico from the remains of an old cold front, it is rare for such storms to grow strong enough to deserve mass evacuations. So far, early signs point to a hurricane-free Republican National Convention at the end of August.

References
Barnes, J., 1999, Florida’s Hurricane History. The University of North Carolina Press.

Weisberg, R.H, and L. Zheng, 2006, "Hurricane storm surge simulations for Tampa Bay", Estuaries and Coasts Vol 29, No. 6A, pp 899-913.

History of Pasco County: The 1921 Hurricane

The 2010 Statewide Regional Evacuation Study for the Tampa Bay Region

The Tampa Bay Catastrophic Plan for a Category 5 $250 billion hurricane

Jeff Masters

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1336. fredwx
4:57 PM GMT on August 21, 2012
More on the 1921 and 1848 Tampa Hurricanes

1921 Tampa Hurricane


The Great Tampa Gale of 1848

Member Since: June 8, 2005 Posts: 221 Comments: 261
1335. aspectre
4:03 PM GMT on August 15, 2012
1284. catastropheadjuster: I read where they went up with the amount of storms we might get this year. But what I'm confused about is El nino is here or fixing to be and with the cooling of the waters and all if I'm reading that right,how can we have more storms? I mean right know we have 93l but it's heading out to sea.
It seems like the dust is gonna kill everything. Also some folks talking about the MJO isn't going to be much of one know, so how can we get more storms?
What is their thinking? Do they possibly see something going on further down the road than we do? I'm just down right a little confused.


Meh, the Season is confused, and the experts are confuzzled.

A very weak ElNino arrived last week, but there's a month-or-two time-lag before the Atlantic feels it.
Another confounding factor is that the EastPacific offa Mexico is relatively cooler than expected for a standard ElNino. And it's the warmer EastPacific that sends the shear over the Gulf, the Caribbean, and the lowerNorthAtlantic.
The Gulf, the Caribbean, and the NorthAtlantic haven't cooled.

SAL dust? Should lessen with the seasonally-expected rain blobs traversing NorthAfrica.

Their thinking? "We screwed up in not predicting the May and June TropicalStorms. Since we said that the Season wouldn't begin until August, then adding those 4 early TCs to our original prediction would mean that our SeasonTotal numbers hafta go up." And NOTHING more.

MJO? Ernesto and TD.7 popped up when the MJO sucked the max-most. So any improvement in uplift should help cyclogenesis.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
1334. Skyepony (Mod)
3:40 PM GMT on August 15, 2012
Quoting AussieStorm:
State of the Climate
Global Analysis
July 2012
National Oceanic and Atmospheric Administration
National Climatic Data Center

Arctic sea ice is 2nd lowest July extent on record Link


It's fallen off since.


They are calling that Arctic storm beginning of Aug that busted so much up ice The Great Arctic Storm of 2012. Before & after.
Member Since: August 10, 2005 Posts: 173 Comments: 38152
1333. PRweathercenter
3:33 PM GMT on August 15, 2012
Member Since: July 21, 2010 Posts: 60 Comments: 1011
1332. washingtonian115
3:20 PM GMT on August 15, 2012
Interesting that the models try to take future Gordon up to a hurricane.Maybe it won't be a weak storm after all?.Looks like this will be another season where conditions are more favorable outside of the MDR.
Member Since: August 14, 2010 Posts: 10 Comments: 17081
1331. AussieStorm
3:20 PM GMT on August 15, 2012
Quoting TropicalAnalystwx13:

112 knots?! That's a borderline Category 4.

Good thing that's probably overdone...for the Azores at least.

We'll have to wait and see, won't we. I think a Cat 1 or 2 don't know about a Cat 4.
Member Since: September 30, 2007 Posts: 9 Comments: 15938
1330. WunderAlertBot (Admin)
3:19 PM GMT on August 15, 2012
JeffMasters has created a new entry.
1329. TropicalAnalystwx13
3:18 PM GMT on August 15, 2012
Quoting AussieStorm:



112 knots?! That's a borderline Category 4.

Good thing that's probably overdone...for the Azores at least.
Member Since: July 6, 2010 Posts: 113 Comments: 32265
1328. AussieStorm
3:16 PM GMT on August 15, 2012
State of the Climate
Global Analysis
July 2012
National Oceanic and Atmospheric Administration
National Climatic Data Center

Arctic sea ice is 2nd lowest July extent on record Link
Member Since: September 30, 2007 Posts: 9 Comments: 15938
1327. SFLWeatherman
3:15 PM GMT on August 15, 2012
Member Since: May 23, 2012 Posts: 0 Comments: 4672
1326. cyclonekid
3:14 PM GMT on August 15, 2012
Looks like it's organizing to me. We could see a special advisory/renumber soon. Either that, or a ~100% percentage at 2pm with Tropical Depression Eight at 5pm.

Member Since: July 14, 2009 Posts: 51 Comments: 1731
1324. bappit
3:12 PM GMT on August 15, 2012
Here's the CPC tropical hazards outlook issued yesterday.

Member Since: May 18, 2006 Posts: 10 Comments: 6061
1323. jascott1967
3:09 PM GMT on August 15, 2012
Quoting Patrap:
....Tie dye on the highway
See the garlands in your hair
If you're goin' my way, come along
What a beautiful sky at we just have to stop and stare
See the beautiful colours fill the air




Robert Plant
Member Since: August 16, 2007 Posts: 0 Comments: 614
1322. AussieStorm
3:09 PM GMT on August 15, 2012
Quoting washingtonian115:
When I meant that it looks like land will be affected in the process is that eventually 93L will affect land.


Member Since: September 30, 2007 Posts: 9 Comments: 15938
1321. Bobbyweather
3:08 PM GMT on August 15, 2012
Quoting washingtonian115:
When I meant that it looks like land will be affected in the process is that eventually 93L will affect land.

Oh, why didn't you say so? Because you said "Code red" and "land" at the same time, I was confused. I'm sorry for the misunderstanding.
Of course, 93L will affect the Azores eventually.
Member Since: September 7, 2006 Posts: 89 Comments: 2655
1320. washingtonian115
3:05 PM GMT on August 15, 2012
Quoting Bobbyweather:

I said a few days. In my opinion, that won't affect development that much.
When I meant that it looks like land will be affected in the process is that eventually 93L will affect land.
Member Since: August 14, 2010 Posts: 10 Comments: 17081
1319. unknowncomic
3:04 PM GMT on August 15, 2012
Quoting bappit:
Despite all the talk about MJO on this blog, it appears that it is kind of weak currently. See the bottom right corner of this graph going back to 2005.Link.

I like that this graph goes back a few years. It gives a sense of the range of amplitudes.
Not strong yet, but this ensemble shows it getting stronger towards the end of the month, I think.
Member Since: August 2, 2011 Posts: 0 Comments: 2038
1318. ncstorm
3:01 PM GMT on August 15, 2012
Quoting Estsurf:
Can someone post a link to the forecast model pages that you use, like the ones ncstorm posts? Thx


Link
Member Since: August 19, 2006 Posts: 13 Comments: 15666
1317. AussieStorm
2:59 PM GMT on August 15, 2012
Quoting yoboi:


cantore lurks in here often...

And he is very welcome to also. If Mr Cantore is here, he can follow me on Tweeter.... @gsdavo1975
Member Since: September 30, 2007 Posts: 9 Comments: 15938
1315. houstonstormguy
2:58 PM GMT on August 15, 2012
Quoting weaverwxman:
Largo i think your 600,000 number is a little on the high side for the RNC maybe more like 16,000 visitors.



Or maybe even 6,000. Only about 2,000 delegates and alternates.
Member Since: September 18, 2007 Posts: 0 Comments: 180
1314. Bobbyweather
2:57 PM GMT on August 15, 2012
Quoting washingtonian115:
The Azores...

I said a few days. In my opinion, the Azores won't affect development that much.
Member Since: September 7, 2006 Posts: 89 Comments: 2655
1313. STXHurricanes2012
2:57 PM GMT on August 15, 2012
More than likely it was a hiccup in the 6z gfs.
Member Since: June 4, 2012 Posts: 0 Comments: 767
1312. unknowncomic
2:57 PM GMT on August 15, 2012
Seems to me a few fronts/troughs pushing into the Atlantic takes care of the dry air this time of year.
Weakening/strengthening Bermuda high pressure also helps with the substinence.
Member Since: August 2, 2011 Posts: 0 Comments: 2038
1311. washingtonian115
2:57 PM GMT on August 15, 2012
Quoting ncstorm:


the name Helene sounds like it going to be bad..a woman and her fury is not to be played with..
And if it had another L in it you could find hell.Lol.We haven't had a interesting "H" storm since Hugo all though Hanna did cause a large amount of deaths and I bet she was a pest to track...
Member Since: August 14, 2010 Posts: 10 Comments: 17081
1310. AussieStorm
2:56 PM GMT on August 15, 2012
Jim Cantore ‏@JimCantore
With eyes on Tampa at the end of the month, here is a little #Tampa #hurricane history from Dr. Jeff Masters: http://www.wunderground.com/blog/JeffMasters/comme nt.html?entrynum=2185 #GOP2012
Member Since: September 30, 2007 Posts: 9 Comments: 15938
1309. bappit
2:55 PM GMT on August 15, 2012
Despite all the talk about MJO on this blog, it appears that it is kind of weak currently. See the bottom right corner of this graph going back to 2005.Link.

I like that this graph goes back a few years. It gives a sense of the range of amplitudes.
Member Since: May 18, 2006 Posts: 10 Comments: 6061
1308. Patrap
2:55 PM GMT on August 15, 2012
Sorry?

pppfth,



I'm elated.
Member Since: July 3, 2005 Posts: 426 Comments: 128645
1307. AussieStorm
2:54 PM GMT on August 15, 2012
I am sorry to say but the GFS 06Z run has backed off on development in the GOM/BOC.
Loop

Check out the Low in Canada
Member Since: September 30, 2007 Posts: 9 Comments: 15938
1306. stoormfury
2:54 PM GMT on August 15, 2012
93L seems to be TS status. there appears to be a very small cdo, which at times gives the impression of a tiny pjnhole eye
Member Since: August 22, 2006 Posts: 0 Comments: 2713
1305. Estsurf
2:53 PM GMT on August 15, 2012
Can someone post a link to the forecast model pages that you use, like the ones ncstorm posts? Thx
Member Since: July 5, 2011 Posts: 0 Comments: 2
1304. Patrap
2:53 PM GMT on August 15, 2012
....Tie dye on the highway
See the garlands in your hair
If you're goin' my way, come along
What a beautiful sky at we just have to stop and stare
See the beautiful colours fill the air


Member Since: July 3, 2005 Posts: 426 Comments: 128645
1303. ncstorm
2:52 PM GMT on August 15, 2012
Quoting washingtonian115:
If this becomes Helene Isaac will likely become that weak storm in the Gulf.Helene better not raise hell.Lol.


the name Helene sounds like it going to be bad..a woman and her fury is not to be played with..
Member Since: August 19, 2006 Posts: 13 Comments: 15666
1302. NttyGrtty
2:52 PM GMT on August 15, 2012
For numbers people...

Link
Member Since: February 11, 2010 Posts: 0 Comments: 838
1301. LostTomorrows
2:51 PM GMT on August 15, 2012
93L is definitely going to become TD8, perhaps even Gordon, later today. Unless something cataclysmic happens to its circulation. It looks like it's getting its act together rather quickly.
Member Since: August 26, 2008 Posts: 0 Comments: 602
1300. ncstorm
2:50 PM GMT on August 15, 2012
The GFS precip for Mexico/Texas through 240 hours


HPC totals for the next 5 days
Member Since: August 19, 2006 Posts: 13 Comments: 15666
1299. VR46L
2:50 PM GMT on August 15, 2012
Quoting washingtonian115:
Yes code red in the Atlantic.Unfortunately it looks like land will be affected in the process.


From what I can tell the front currently moving into the British Isle is to stall for at least a week and its there that 93L will interact with it ....going to be a extremely wet week ahead ....
Member Since: March 1, 2012 Posts: 0 Comments: 6927
1298. washingtonian115
2:49 PM GMT on August 15, 2012
Quoting ncstorm:


Lets hope not:(
If this becomes Helene Isaac will likely become that weak storm in the Gulf.Helene better not raise hell.Lol.
Member Since: August 14, 2010 Posts: 10 Comments: 17081
1297. kshipre1
2:49 PM GMT on August 15, 2012
could be but that's what everyone thought about Gordon. I guess with less dry air and more possible moisture, a big storm could form but too early to tell.
Quoting ncstorm:


Lets hope not:(
Member Since: July 12, 2010 Posts: 0 Comments: 1130
1296. ncstorm
2:47 PM GMT on August 15, 2012
Quoting washingtonian115:
Looks like we currently have model support for our fat wave over Africa that all ready has a legacy of being Deadly and causing damage.Hopefully it won't continue the same for the Caribbean U.S and Bermuda?.


Lets hope not:(
Member Since: August 19, 2006 Posts: 13 Comments: 15666
1294. Waltanater
2:46 PM GMT on August 15, 2012
Quoting CosmicEvents:
It's got to be killing Nea that he didn't find this factoid first:)
Nice find Georgia.
Then it will go back down to 314,159,264. LOL
Member Since: May 16, 2010 Posts: 0 Comments: 1472
1293. AussieStorm
2:45 PM GMT on August 15, 2012
Quoting stoormfury:
wave over central africa seems to follow the same track. shear is in the acceptable range but what could be an impediment to early development, is the marginal sst and dry air in the catl

It's true the CATL is dry but it's moving west and the EATL is very moist with a new t-wave set to emerge in the next few days.


Loop
Member Since: September 30, 2007 Posts: 9 Comments: 15938
1292. washingtonian115
2:45 PM GMT on August 15, 2012
Quoting ncstorm:
the 06z Nogaps at 180 hours
Looks like we currently have model support for our fat wave over Africa that all ready has a legacy of being Deadly and causing damage.Hopefully it won't continue the same for the Caribbean U.S and Bermuda?.
Member Since: August 14, 2010 Posts: 10 Comments: 17081
1291. Waltanater
2:42 PM GMT on August 15, 2012
Quoting GeorgiaStormz:
US population hits maths milestone


8/14/12 TUE

Figuring out the number of American residents got as easy as pi on Tuesday (local time) as the United States touched a rare mathematical and demographic milestone.

The Census Bureau said that the United States reached 314,159,265 residents, or the mathematical ratio pi times 100 million, shortly after 2.29 pm.

Pi, or 3.14159265, is the mathematical constant that is the ratio of a circle's circumference to its diameter. It often is approximated as 22/7.
Interesting!
Member Since: May 16, 2010 Posts: 0 Comments: 1472
1290. washingtonian115
2:42 PM GMT on August 15, 2012
Quoting Bobbyweather:

What do you mean? It's 93L, it won't meet land for at least a few days. If you're talking about ex-TD 7, it has a 0% chance.
The Azores...
Member Since: August 14, 2010 Posts: 10 Comments: 17081
1289. AtHomeInTX
2:41 PM GMT on August 15, 2012
Quoting ncstorm:
the 00z CMC..hour 240


There it is. Lol.
Member Since: August 24, 2010 Posts: 0 Comments: 245
1288. ncstorm
2:39 PM GMT on August 15, 2012
the 00z CMC..hour 240


Member Since: August 19, 2006 Posts: 13 Comments: 15666
1287. icmoore
2:37 PM GMT on August 15, 2012
Quoting StormTracker2K:
Parts of C FL got absolutely BLASTED yesterday.

This is from Cape Canaveral yesterday.


This is from Downtown Orlando just as the storms rolled in.


Lightning pic from Edgwater


Great pictures! That line of storms sure had the radar lit up yesterday!
Member Since: July 18, 2005 Posts: 9 Comments: 4146
1286. AtHomeInTX
2:37 PM GMT on August 15, 2012
I know y'all have better models than I but on the CMC it showed something moving toward the east coast at the end of the run. The EURO has something out there too but in a different place.

Member Since: August 24, 2010 Posts: 0 Comments: 245

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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