The nation's unprecedented April tornado-fest continued full force last night, with NOAA's Storm Prediction Center logging 57 tornado reports, 295 cases of damaging thunderstorm winds, and 254 reports of large hail. The 2-day tornado count from this latest huge April tornado outbreak is already 102. With another "high risk" forecast for tornadoes today, the tornado total for this week's outbreak may rival the April 14 - 16 tornado outbreak (155 confirmed tornadoes) as the greatest April tornado outbreak in history. It is unprecedented to have two such massive tornado outbreaks occur so close together, and the April preliminary tornado count of 654 is truly stunning. Even adjusting this number downwards 15% (the typical over-count in preliminary tornado reports) yields a probable April tornado total of 550. This easily crushes the previous April tornado record of 267, set in 1974. An average April has "only" 163 tornadoes, so we are already 300% over average for the month, and may approach 400% after today's outbreak. According to a list of tornado outbreaks maintained by Wikipedia, only two other tornado outbreaks have had as many as 150 twisters--the May 2004 outbreak (385), and the May 2003 outbreak (401). One positive note--there has only been one violent EF-4 or stronger tornado this year, despite the fact we've already had about 2/3 of the 1200 tornadoes one typically gets for the entire year. Over the past 20 years, we've averaged 7 violent EF-4 or EF-5 tornadoes per year, so we should have had 4 or 5 of these most dangerous of tornadoes so far this year.
Figure 1. Satellite image of last night's storm at 8pm EDT April 26, 2011. Image credit: NASA/GSFC.
Fortunately, no one was killed in last night's tornado frenzy, but four twisters caused injuries, with 7 injuries in Hesterman, Mississippi, and 3 in Beekman, Louisiana. Over 100 homes were damaged when a tornado struck Edom, Texas, approximately 75 miles East of Dallas. One woman was injured when her mobile home was destroyed. The only killer tornado of the current outbreak occurred on Monday night at 7:30 pm CDT when a 1/2 mile-wide EF-2 tornado struck the small town of Vilonia, Arkansas. Four people died in the town, where 50 - 80 buildings were destroyed. Tornado warnings were issued 30 minutes before the storm hit, contributing to the relatively low loss of life.
Figure 2. Storm chaser video of a tornado yesterday in Ben Wheeler, Texas.
Another very dangerous tornado outbreak expected today
The busiest April in history for tornadoes continues full-force today, as NOAA's Storm Prediction Center has issued their highest level of severe weather potential, a "High Risk" forecast, for Northern Alabama, Southern Tennessee, and adjoining portions of Georgia and Mississippi. This is the second day in a row, and third time this year, that SPC has issued a "High Risk" forecast. The devastating North Carolina tornado outbreak of April 16, which generated 52 confirmed tornadoes that killed 24 people in North Carolina and 2 people in Virginia, was the other "high risk" day. Numerous tornado warnings have already been issued in Tennessee, Kentucky, Georgia, Mississippi, Arkansas, Ohio, and Alabama this morning, but today's main action is expected to erupt late this afternoon as the cold front from a low pressure system currently over Arkansas moves eastwards over the "high risk" area. Strong daytime heating in a very moist, unstable airmass will allow a tremendous amount of energy to build up ahead of the front. The arrival of the cold front will force the warm, moist air upwards, allowing the pent-up energy to burst out and fuel supercell thunderstorms.
Related post: Are tornadoes getting stronger and more frequent?
Figure 3. Severe weather threat for Wednesday, April 27, 2011.
Unprecedented flooding predicted on Ohio River
This week's storm system, in combination with heavy rains earlier this month, have pushed the Ohio River and Mississippi River to near-record levels near their confluence. The Ohio River at Cairo, Illinois is expected to crest at 60.5 feet on May 1. This would exceed 100-year flood stage, and be the highest flood in history, besting the 59.5' mark of 1937. Heavy rains of 10 - 15 inches have inundated the region over the past few days, and one levee breach at Black River levee near Poplar Bluff, Missouri, has resulted in the evacuation of over 500 homes. Poplar Bluff has received 15.45" of rain since Friday morning. The greatest rain gauge-measured precipitation from the storm occurred in Springdale, Arkansas, where 19.70" inches has fallen since Friday morning.
Figure 4. The latest River Flood Outlook from NOAA shows major flooding is occurring over many of the nation's major rivers.
Extraordinary intentional levee breach of Mississippi River halted by lawsuit
In a sign of just how extreme this flooding situation is, yesterday the Army Corps of Engineers, which is responsible for flood control efforts on the Mississippi River, announced plans to intentionally destroy a levee protecting the west bank of the Mississippi River in Southwest Missouri. The destruction of the levee is intended to relieve pressure on the levees at Cairo, Illinois, at the confluence of the Mississippi and Ohio Rivers. Cairo is currently under a voluntary evacuation order. The levee to be destroyed, located at Birds Point, is called a "fuse-plug" levee, and was designed to be destroyed in the event of a record flood. The levee protects 132,000 acres of prime farmland along the New Madrid Spillway, which is designed to take 550,000 cubic feet per second of water flow out of the Mississippi and redirect it down a 3 - 10 mile wide, 36 - 56 mile long path along the west side of the Mississippi. An 11-mile long section of the levee upstream at Birds Point, and 5-mile long stretch at the downstream end, are set two feet lower than the surrounding levees and filled with holes to accommodate dynamite. These levees will be destroyed if the Army Corps has its way, but a lawsuit by the state of Missouri is currently blocking the way. The Army Corps has now agreed to wait until Saturday to decide whether or not to blow the levee. The Army Corps' website has an unofficial damage estimate of $100 million for destroying the levees and flooding the New Madrid Spillway. At least 100 people live in the spillway and have been evacuated, and it would likely take many years for the farms to recover after flooding. The levees have been blown and the spillway opened only once before, back during the record flood of 1937.
Midwest deluge enhanced by near-record Gulf of Mexico sea surface temperatures
The deluge of rain that caused this flood found its genesis in a flow of warm, humid air coming from the Gulf of Mexico. Sea surface temperatures (SSTs )in the Gulf of Mexico are currently close to 1 °C above average. Only two Aprils since the 1800s (2002 and 1991) have had April SSTs more than 1 °C above average, so current SSTs are among the highest on record. These warm ocean temperatures helped set record high air temperatures in many locations in Texas yesterday, including Galveston (84°F, a tie with 1898), Del Rio (104°F, old record 103° in 1984), San Angelo (97°F, old record 96° in 1994). Record highs were also set on Monday in Baton Rouge and Shreveport in Louisiana, and in Austin, Mineral Wells, and Cotulla la Salle in Texas. Since this week's storm brought plenty of cloud cover that kept temperatures from setting record highs in many locations, a more telling statistic of how warm this air mass was is the huge number of record high minimum temperature records that were set over the past two days. For example, the minimum temperature reached only 79°F in Brownsville, TX Monday morning, beating the previous record high minimum of 77°F set in 2006. In Texas, Austin, Houston, Port Arthur, Cotulla la Salle, Victoria, College Station, Victoria, Corpus Christi, McAllen, and Brownsville all set record high minimums on Monday, as did New Orleans, Lafayette, Monroe, Shreveport, and Alexandria in Louisiana, as well as Jackson and Tupelo in Mississippi. Since record amounts of water vapor can evaporate into air heated to record warm levels, it is not a surprise that incredible rains and unprecedented floods are resulting from this month's near-record warm SSTs in the Gulf of Mexico.
Figure 5. Departure of sea surface temperature from average for April 25, 2001. Image credit: NOAA/NESDIS.
Fierce winds fan Texas, New Mexico fires
Fierce winds fanned raging fires across eastern New Mexico and Western Texas yesterday, thanks to a powerful flow of air feeding into the Midwestern storm system. Temperatures in the upper 80s and low 90s combined with humidities less than 10% combined to make yesterday a nightmare fire day for firefighters attempting to control the worst springtime fires in the history of the region. At 3:53 pm MDT yesterday in Carlsbad, New Mexico, the temperature was 87°F, winds were 38 mph gusting to 46, and the humidity was 8%--a perfect storm for extreme fire weather. In Fort Stockton, Texas near the huge Rock House fire, the temperature was 91°F, winds were 35 mph gusting to 44, visibility was reduced to 5 miles due to haze and smoke, and the humidity was 5% at 5:53pm CDT. According to the Interagency Fire Center, wildfires in 2011 have already burned nearly 2.3 million acres in the U.S. This is the greatest acreage on record so early in the year, and is more area than burned all of last year. The largest U.S. acreage to burn since 1960 was the 9.9 million acres that burned in 2007, so we area already 25% of the way to the all-time record fire year--with summer still more than a month away. The fire weather forecast for today is better then yesterday, with winds not expected to blow nearly as strong.
Figure 6. Major wildfires and smoke plumes as visualized using our wundermap with the "fire" layer turned on.
For those who want to lend a helping hand to those impacted by the widespread destruction this month's severe weather has brought, stop by the portlight.org blog.
Jeff Masters
I haven't seen a storm like this in quite some time. Still no rain in Seguin, Tx. Pic taken in Seguin storm near Martindale.
Mississippi @ Burlington (
BURGuy)
Seating along the shore
Taken within minutes after the storm cell had passed directly overhead.
This is a shot of a lightning strike associated with some severe storms moving through this evening in Southaven, MS.
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I am trying to figure out why the state of Missouri is suing the Army CoE for protecting the largest number of people possible. The levee they are trying to destroy is DESIGNED to be destroyed, and flooding some farmland is a vastly better alternative to flooding a city. People complaining about it knew that their land could be flooded in the event of a record flood event. Its like people living in the Bonnet Carre' spillway in Louisiana...
The best resolution to the drought is to get about an inch a day for 5-7 days. That will soak in VERY well, with limited runoff.
And mind you, this is just in the U.S. And just this month.
Incredible, ain't it? It's either magic or a political ploy by Mother Nature, because it can't possibly be anything else... ;-)
Interesting idea, but I would have expected that the smoke would result in a lot of smaller hail particles. Heterogeneous nucleation at a lot of low energy sites (i.e. smoke particles) would give smaller hail particles than homogeneous nucleation on a smaller number of sites. If you consider clumping of smaller hail then maybe you would get a lot of larger hail. I am not answering this from a meteorological viewpoint (I am not a met), but I am familiar with nucleation in my own field.
anybody spot locusts yet?
I don't understand what race relations (an issue that goes back decades) has to do with whether to let a levee function as it was designed. It doesn't matter who owns the farmland - what matters is that if the levee is not allowed to work as it was designed, a city could be flooded. If the Army CoE waits for the lawsuit to finish, blowing the levee will be a moot point, and hundreds of people would have lost their livelihoods and homes in the process of waiting for the glacial pace of the legal system.
National Weather Service New Orleans la
1032 am CDT Wednesday Apr 27 2011
Discussion...so far not much has changed in the forecast. If we can
get enough forcing there is ample shear and instability to help
produce severe storms. This mornings sndg showed a very unstable
environment with MLCAPE of 2700 j/kg...Li of -10 and Vermont near 30c.
That said there is also a cap at h9 and another at h75. Sndg also
shows a lot of shear with a very favorable hodograph. The cold
front is still expected to push through the region this afternoon and
this will provide some forcing but will we get any extra lift from
the short wave that will move through the Lower/Middle MS valley. Again it
looks like most of the lift will remain north of the the region
but across the northern 3rd of the County Warning Area there should be enough forcing
with 55-70kts of middle level flow moving in to help initiate some rain showers
and thunderstorms and rain this afternoon. If thunderstorms and rain are able to develop there is a very
good chance that they could go severe and go severe quickly. All
modes of severe weather will be possible with any severe
thunderstorm. Once the front moves by convection if any will come
to a quick end. No update needed for the grids and zones at this
time. /Cab/
"However, atmospheric indicators of ENSO continue to be at odds with recent trends in the ocean, and remain consistent with a well developed La Niña event. The latest 30-day Southern Oscillation Index (SOI) value (+30.2) is only a little short of the highest April monthly value on record (+31.7, recorded in 1904), and has remained consistently high throughout the event."
No, but the Love Bugs are out in full force!!! ARG!
Excellent points. Dr. Masters stated that the levee was previously blown 74 years ago, so people in the spillway have obviously known for many decades that they are living in an area that could be flooded. I don't blame them for being upset that it's come to this, but I do fault them for being so short-sighted as to ignore many years of warnings.
In reading a bit about this, I see that even people behind the suit acknowledge that there really are no other viable options; they are apparently simply lining things up so they'll be compensated by the government once the damage is done--so it is about the money after all.
Thanks for the comprehensive update, Doc! Amazing events.
Love the images.
Howdy, folks. :)
"Just" isn't the same as "unprecedented", is it?
But couldn't the opposite have been said when the levees were first built? Putting in the levees means protecting that rural land at the expense of land further downstream which is not behind levees. The water has to go somewhere...
I don't know all the details of this situation, but it seems to me like the best solution is to take whichever course leads to the fewest people affected and lowest overall economic cost.
The atmospheric pattern can't be maintained for too long if the ocean doesn't support it, but it does suggest that an El Nino will not be as ready to come on this winter, and possibly a return to at least a weak La Nina. It's indicating the tendency for La Nina conditions to be the rule, not the exception, now that the PDO has switched to negative.
But that would require common sense!
Buckle up folks, gonna be a hellava ride
From your post this morning:
The devastating North Carolina tornado outbreak of April 16, which generated 52 confirmed tornadoes that killed 24 people in North Carolina and 2 people in Virginia...
...Even adjusting this number downwards 15% (the typical over-count in preliminary tornado reports) yields a probable April tornado total of 550...
Were the 52 confirmed tornadoes for the entire multi-state outbreak or only those that were confirmed in North Carolina?
Raleigh, NC April 16th Tornado Summary
click for storm reports
Please note: On March 8, 2011, the proximity space/time rule is no longer being utilized to de-duplicate events and minimal filtering is now applied to the decoded reports. All comments/remarks in the LSRs are captured on the raw files and the users can decide, for their own purposes, the best way to remove duplicate reports from the LSR's.
SPC Storm Reports
If the 52 confirmed tornadoes represent a total for the entire one day outbreak, the preliminary count would have to be reduced by about 63%.
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