Caribbean disturbance slow to develop; 5 EF-5 tornadoes this year confirmed
The tropical disturbance (Invest 93L) that crossed over Florida on Wednesday, bringing welcome rains of 1 - 3 inches, is now a naked swirl of low clouds over the central Gulf of Mexico. The disturbance is embedded in a large area of dry air associated with an upper level low pressure system, and this dry air is discouraging development. 93L is also moving into a region of moderate wind shear of 10 - 20 knots, and NHC is giving 93L a 0% chance of developing into a tropical depression before the storm makes landfall in Mexico south of Brownsville on Saturday. There are a few heavy thunderstorms trying to fire up near the center of 93L's fairly well-formed circulation, but I don't think this storm is going to bring more than 1 - 2 inches of rain to the coast on Saturday.

Figure 1. Morning satellite image of the Central Caribbean disturbance.
Central Caribbean disturbance 94L
Disorganized heavy thunderstorm activity continues in the region between Central America and Jamaica. Wind shear has fallen to the moderate range, 10 - 20 knots, and is predicted to continue to fall over the next two days. This should allow the disturbance, dubbed Invest 94L by NHC on Friday afternoon, to increase in organization, though it will take many days for it to approach tropical depression status, since it is so large and poorly organized. The last two runs of the NOGAPS model have developed the disturbance into a tropical depression or storm by early next week, with the system moving northwards into Jamaica, the Cayman Islands, and eastern Cuba. The other major models do not show the disturbance developing during the coming week. NHC is giving the disturbance a 10% of developing into a tropical depression by Sunday. A surge of moisture accompanying a tropical wave may aid development when the wave arrives in the Western Caribbean on Sunday. Water temperatures in the Central Caribbean are about 1°C above average, 29°C, which is plenty warm enough to support development of a tropical storm. Residents of Jamaica, eastern Cuba, the Cayman Islands, Haiti, and the Dominican Republic should anticipate the possibility that heavy rains of 2 - 4 inches may affect them today through Sunday.
Five EF-5 tornadoes confirmed in 2011
The National Weather Service in Oklahoma City announced Wednesday that the violent tornado that hit Binger, El Reno, Peidmont, and Guthrie, Oklahoma on May 24, killing nine people, was an EF-5 with winds greater than 210 mph. The rating was given based on measurements made by a University of Oklahoma portable "Doppler on wheels" radar. The long track, large wedge tornado caused extensive damage, with well built houses cleanly swept from their foundation and trees debarked. This tornado brings the total number of EF-5 tornadoes this year to five, tying 2011 with 1953 for 2nd place for greatest number of these top-end tornadoes in one year. Only 1974 (six) had more. The EF-5 tornadoes of 2011:
1) The April 27, 2011 Neshoba/Kemper/Winston/Noxubee Counties, Mississippi tornado (3 killed, 29 mile path length.)
2) The April 27, 2011 Smithville, Mississippi tornado (22 killed, 15 mile path length.)
3) The April 27, 2011 Hackleburg, Alabama tornado (71 killed, 25 mile path length.)
4) The May 22, 2011 Joplin Missouri tornado (138 killed, 14 mile path length.)
5) The May 24, 2011 Binger-El Reno-Peidmont-Guthrie, Oklahoma tornado. (9 killed, 75 mile path length.)

Figure 2. Aerial view of damage from the May 22, 2011 Joplin, Missouri tornado. Image credit: Wikipedia.
A few other remarkable statistics on the tornado season of 2011, compiled from NOAA's official press release and Wikipedia's excellent tornado pages:
- The April 25 - 28 tornado outbreak, with 330 tornadoes, was the largest tornado outbreak of three days or less duration on record. The previous record was 148 tornadoes, set during the April 3 - 4, 1974 Super Outbreak.
- For April 27, 186 tornadoes have been confirmed. This is the largest 1-day tornado total on record, beating the 148 recorded in 24 hours on April 3 - 4, 1974.
- The April 14 - 16 tornado outbreak, with 162 confirmed tornadoes, ranks as the fourth largest tornado outbreak of three days or less duration on record.
- The May 21 - 26 tornado outbreak, with 158 confirmed tornadoes, ranks as the 5th largest 6-day or shorter tornado outbreak on record. A May 2003 6-day outbreak had 289 tornadoes, and a May 2004 6-day outbreak had 229 tornadoes. The year 2011 now has three of the top five tornado outbreaks on record.
- April confirmed tornado total was 683, making it the busiest tornado month on record. The previous record was 542 tornadoes, set in May 2003. The previous April record was 267 tornadoes, which occurred in April 1974. The 30-year average for April tornadoes is 135.
- If the three deaths in Massachusetts from Wednesday's tornadoes are confirmed, this year's tornado death toll will be 522, beating 1953 as the deadliest tornado year since modern tornado records began. That year, 519 people died, and three heavily populated cities received direct hits by violent tornadoes. Waco, Texas (114 killed), Flint, Michigan (115 killed), and Worcester, Massachusetts (90 killed) all were hit by violent F-4 or F-5 tornadoes. A similar bad tornado year occurred in 1936, when violent tornadoes hit Tupelo Mississippi (216 killed), and Gainesville, Georgia (203 killed.) During that time period, the tornado death rate per million people was 60 - 70 times as great as in the year 2000 (Figure 4), implying that this year's tornadoes would have killed many thousands of people had we not had our modern tornado modern warning system.
- The May 22, 2011 Joplin, Missouri tornado killed 138 people and injured 1150, making it the deadliest U.S. tornado since 1947, and 8th deadliest in history. The $1 - $3 billion estimate of insured damage makes it the most expensive tornado in history.
- Damage from the April 25 - 28 super tornado outbreak was estimated at $3.5 - $6 billion, making it the most expensive tornado outbreak of all-time.
- The tornado that hit Springfield, Massachusetts on June 1 was at least an EF-3 with 136 - 165 mph winds. It was only the 9th EF-3 or stronger tornado to hit Massachusetts since 1950, and the third deadliest, with three deaths.
- The year 2011 now ranks in 3rd place behind 1974 and 1965 for highest number of strong to violent EF-3, EF-4, and EF-5 tornadoes (Figure 3.)

Figure 3. Number of strong to violent EF-3, EF-4 and EF-5 tornadoes from 1950 to 2011. The year 2011 now ranks in 3rd place behind 1974 and 1965. There is not a decades-long increasing trend in the numbers of these most dangerous of tornadoes. Image credit: NOAA/National Climatic Data Center (updated using stats for 2008 - 2011 from Wikipedia.)

Figure 4. Death rate per million people per year in U.S., 1875-2000. Thin line with dots is raw rate, curved thick line is death rate, filtered by 3-point median and 5-point running mean filter, and straight solid lines are least squares fit to filtered death rate for 1875-1925 and 1925-2000. Dashed lines are estimates of 10th and 90th percentile death rates from 1925-2000. The death rate fell from 8 per million to .12 per million between 1940 and 2000. Image credit: A Brief History of Deaths from Tornadoes in the United States, Harold Brooks and Charles Doswell III.
Joplin tornado the 7th U.S. billion-dollar weather disaster of 2011
The Joplin tornado is the 7th U.S. weather disaster of 2011 costing more than a billion dollars. With a major flooding disaster coming on the Missouri River, and hurricane season still to come, 2011 has an excellent chance of beating 2008's record of nine billion-dollar weather disasters. The billion dollar weather disasters of 2011 so far:
1) 2011 Groundhog Day's blizzard ($1- $4 billion)
2) April 3 -5 Southeast U.S. severe weather outbreak ($2 billion)
3) April 8 - 11 severe weather outbreak ($2.25 billion)
4) April 25 - 28 super tornado outbreak ($3.5 - $6 billion)
5) Mississippi River flood of 2011 ($9 billion)
6) Texas drought ($1.2 billion)
7) Joplin tornado ($1 - $3 billion)

Figure 5. River flood outlook for the U.S. Image credit: NOAA.
The next U.S. billion-dollar weather disaster: a Missouri River flood?
A great 100-year flood has arrived along the Missouri River and its tributaries from Montana to Nebraska. Record spring rains, combined with snow melt from record or near-record winter and spring snows, brought the Missouri River at Williston, North Dakota to 27.9' yesterday, just an inch short of the highest crest on record (28.0' on 4/01/1912.) Tributaries to the Missouri, such as the Souris River in North Dakota and the North Platte River in Nebraska, are already flooding at all-time record heights. With warm summer temperatures and additional rainfall expected over much of the area during the coming week, snow melt and rain runoff will swell area rivers even further, creating a damaging 100-year flood. Wunderground weather historian Christopher C. Burt has the details in his latest post, and I will be writing more on this latest epic flood next week.
I'll have a new post on Monday, or earlier if the Caribbean disturbance shows significant development.
Jeff Masters
Here it is turning into a monster.
Reader Comments
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The heat of the day combined with shear and dry air has sapped the strength of fledgling 94L. Tonight it will likely perk up again.
Careful! I throw shoes at things that make that noise in the night.
It's not RIP yet until formation chances are dropped to near 0%.
I agree 100%. These things are unpredictable sometimes.
There must be alot of people on this blog that have never been married. If they were, they'd understand the fine art of knowing when to ignore. :)
"Yes, dear"...
;-)
I wouldn't say killing it.
But yes it is currently inhibiting development at the time being. Help is on the way for 94L from a tropical wave, and it should arrive tomorrow.
What do you make of this shear out of the SE tonight?
Thanks Pot. "Carburettor" - well, as you might now, sometimes I use this blog to amplify my English vocabulary, LOL.
Anyone for an AGW debate?
It has been sitting around for a long time with marginal help from the environs.
But with the introduction of a T-Wave, and the fact that it's still there and still a large area, I think that it still has a chance.
I realise the models dont agree with me, but they dont agree with each other either...
However, we do have a blog specifically meant for discussing global warming/climate change Link
I completely agree !!
Don't bring it up here. That's all i'm gonna say.
These monsoonal lows test the patients don't they, lol.
Grosser Fehler! LOL
no no no no it is just doing this mainly because of D-Min but should redevelop by morning
In the gulf, a moderate TS sits there, not good. A hurricane waiting to happen.
Hey Grothar, did you see the new X-Men movie yet? You don't need to read the subtitles LOL
But it would be fun to debate since tropics are quiet.
If this dryseason down here was because of AGW, I say Bring It On!
Been a really nice one.
(I reserve the right to change my mind around August)
Technically they aren't quiet. We have one invest out there in the Atlantic.
What is an X-Men movie? Something where someone was once a man and now is no longer one.
No, Grothar, no mistake. It's really an enrichment. Besides "carburettor" I've gathered in the last days f.e. the new words: prankster, hobgoblin, whiplash. Great, isn't it?
Besides, in respect to weather: Some rain and thunderstorms today near Frankfurt, but nothing serious. Still too dry in my region. In France (Bretagne, Normandie in the northwest) the drought is even more severe. But right now, they get some smaller storms - but from the EAST! Not from the Atlantic (West).
You are very welcome.
It is a word that is quickly dropping out of the language. Being replaced by Induction System, Fuel Injection, and Integrated Control Unit.
Very sad!
Lovely word.
Amusing you are LOL
18Z HWRF for 94L, out in the Atlantic
18Z HWRF for 91E, shows 94L over Cuba
Very Good!
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