WITH STEVE LANORE, CBM APRIL 30, 2018 - SEVEN YEARS AGO: TWISTER MAYHEM / WORLD RECORD, APRIL 27, 2011 - CRU ADJUSTERS

With Steve LaNore, CBM
                                       April 30, 2018

SEVEN YEARS AGO: Twister Mayhem / World Record, April 27, 2011
It was seven years ago, on April 27 2011, that the atmosphere was primed to produce three massive waves of
severe thunderstorms over the southern U.S. from Mississippi and Tennessee to Alabama and Georgia. This
outbreak featured numerous huge tornadoes – they killed over 300 people and did over $5 billion in damage
in ONE day. It also set the world record for tornadoes in a single 24-hour period at 200.

It was a weather scenario forecasters dreaded…a classic “high-risk” event with very strong wind shear and an
unusually moisture-charged atmosphere. In fact there were three days’ lead time that this was going to be a
major outbreak in all respects, a heads-up blessing of 21st century science. Smaller tornado outbreaks began
on April 25th over Texas, by the 27th all the ingredients had lined up for a world-record day of tragic
tornadoes: an epic 200 of them would be produced.

The wind shear was downright ferocious with winds transitioning from 20 mph at the surface to 70 mph at
3,000 feet, rare at that level. This created a very favorable environment for large, long-lasting twisters.

By afternoon, it wound up being a literal barrage of twisters through northern Mississippi and
central/northern Alabama.

The first tornado in nature’s afternoon salvo was a vicious EF-5 that produced extreme devastation on the
north side of Philadelphia, Mississippi around 2:30 p.m. Homes were scraped clean to their foundations,
vehicles were thrown, and the ground itself was scoured out to a depth of two feet. The storm continued for
29 miles while more supercell thunderstorms began to rapidly form within a 150-mile wide swath of eastern
Mississippi and northern Alabama.

A half-hour later, a devastating multiple-vortex tornado struck the city of Cullman, Alabama (south of
Huntsville) around 3:00 p.m. The EF-4 wiped out nearly 900 homes and 100 businesses and even destroyed
the NOAA Weather Radio transmitter located there. It only got worse as the afternoon wore on.

This is one of dozens of large tornadoes that raked Alabama and neighboring states on April 27, 2011.
                               From Charles Whisenant of the Arab, Alabama Tribune.

Tuscaloosa tornado with 190 mph winds; 240 people died in Alabama that day alone with over 2,000 injured from the
   salvo of deadly Supercells. Damage in Alabama was over $4 billion; the tornado pictured here killed 65 people.

The Tuscaloosa tornado after it hammered the city, sporting a monster hook as seen on NWS weather radar.

A testament to good forecasting along with advances in weather science: The Storm Prediction Center (SPC) had the
areas which received the worst tornadoes pinpointed more than two days before the event happened. SPC image.

Unlucky Friday the 13th
The biggest tornado event far in 2018 was Friday, April 13th through Sunday, April 15th…during this three-day
period some 70 tornadoes spun up across the south; many of them hammering Louisiana and Arkansas on the
13th but with the most intense ones striking Virginia and North Carolina on the 15th. The suburbs of
Greensboro, NC took a hit from a high-end EF2 with winds to 135 mph, killing one and doing major damage.

 Hampton elementary school and the surrounding buildings take a hit from the tornado in Greensboro. A total of three
                  schools were in the path of the tornado; school was not in session at the time.

                                      Greensboro damage from Thestate.com

Is this a total loss? You tell me, but no doubt one helluva mess; the Greensboro tornado was 300 yards wide / WITN-TV

Meanwhile, Lynchburg, Virginia was trounced by an EF3 sporting 150 mph winds the same day. No one died in
the Lynchburg event but the twister mauled a widespread area along a 600-yard wide, 20-mile-long path:

Image: Rachael Smith / The Lynchburg News and Advance / Damage in Elon, VA near Lynchburg, April 15, 2018

The Greensboro tornado racked up a greater damage toll despite its shorter path, because it went through a
more developed area. Officials report around $8 million in losses in the Lynchburg area; given the school
damage, a wrecked church and numerous homes and vehicles, the Greensboro tally is likely more than that.

Record Cold April
It’s really quite simple – we’ve had numerous Canadian air masses pushing deep into the Gulf; each one has
brought a batch of dry air that cools more efficiently at night, making for many chilly mornings during the
month. A major blizzard across the upper Midwest earlier in the month also deposited a large snowpack which
allowed the southward-moving air to stay cold longer. Record lows were tied as that system passed through
on April 15.

This pattern is unusual, and in fact it’s been 21 years (1997) since the southern Plains had an April this chilly. A
highly amplified jet stream has helped to keep a deep “dip” over the eastern U.S. (red low on map) which
allows these cold air masses to slip southward more easily.

Preliminary statistics show it’s the coldest April for the southern Plains in 21 years, for instance the 4th coldest
ever for Dallas. It’s THE coldest on record for Minneapolis.

Farther north, Green Bay doubled its previous April snow record; the 15.1” record has stood since 1907 but
the Packers’ hometown got more than 30 inches in April of 2018. Snow drifts reached six feet high as the
Green Bay National Weather Service proved in this Tweet:

Alaska Comes South…
Incredibly cold temperatures for April are perhaps best illustrated by a map. Here, we show how typical April
temperatures in Fairbanks and Anchorage compared to what was experienced across the northern Plains:

This cold regime helped set the stage for a downright epic blizzard for April. This National Weather Service
graphic gives the numbers….

…While another captures the titanic struggle between winter and spring that raged this year in the Plains.

                         Image: Abby Perez-Cassut / Mitchell South Dakota / from NWS website

SO…What about May and June?
The entrenched pattern which persisted all winter and through April is temporarily breaking down, and the
first significant severe event for “Tornado Alley” is looming for May 2. There are likely to be several tornadoes,
possibly strong, within the “enhanced” zone followed by a heavy rainfall event Thursday a bit farther east.

Longer-range models show a weaker version of the winter pattern into mid-May, but as more Gulf moisture
taps into these systems as compared to April, we’ll certainly see a significant increase in severe events. I think
June will be the busiest month of severe weather season this year, and this primarily north of I-40 through the
Midwest and Ohio Valley.

Next month…time to delve into hurricane season once again. Have a great May!

Take Care,

Steve LaNore, CBM

Author, “Twister Tales, Unraveling Tornado Myths”, available on Amazon