MSP Tornado: 6 minute NWS lead time? Joplin: deadliest in 64 years

In all the chaos Sunday, chalk one up for our local NWS office in Chanhassen.

It appears tornado warnings were issued by local NWS at least 6 minutes in advance of the first tornado touchdown, and a tornado watch was posted by SPC 2 hours in advance.

Car crushed by tree in North Minneapolis Sunday. (NWS photo)

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The NWS storm summary will confirm the timing, but after sifting through storm reports and talking with NWS today here's a chronology of events so far.

12:10pm CDT SPC in Norman, Oklahoma issues tornado watch #322 for parts of Minnesota, Iowa and Wisconsin including the Twin Cities Metro.

2:10pm CDT First tornado warning issued for Minneapolis by Chanhassen NWS Office.

2:16pm CDT First reported tornado touchdown sighting near Highway 100 & I-394 in St. Louis Park.

The Watch:

Tornado Watch #322 was issued in timely fashion Sunday, with a 2-hour lead time before the tornado dropped from the sky over St. Louis Park.

Tornado watch #322 graphic from SPC.

Tornado Watch #322 text from SPC

The SPC 2 hour lead time on the watch was critical and may have alerted residents well in advance of the possibility of tornadoes.

Developing "Hook Echo":

By 2:05pm is clear that storms are becoming tornadic over the metro. A clear hook echo is visible over St. Louis Park on the NWS doppler reflectivity image below.

Tornado Warning issued at 2:10pm CDT:

I talked with the Chanhassen NWS today to confirm that the first tornado warning was issued at 2:10pm CDT Sunday. This appears to be about 6 minutes before the first reported touchdown near Highway 100 & 394 in St. Louis Park.

By 2:14 pm rotation is clearly visible in the form of a "velocity couplet" on NWS doppler velocity scans. Details from NWS below:

"Below is a radar image from Sunday afternoon. This image shows SRM (Storm Relative Motion) and is used to diagnose circulation in thunderstorms. The couplet of bright green immediately adjacent to red indicates strong low level rotation in the thunderstorm. The following image below shows radar reflectivity at the same time on Sunday afternoon, at 2:14 PM CDT. Below is a radar velocity image of the storm as the rotation was passing just to the east of Highway 100 and Golden Valley."

The at 2:16pm, the first tornado sighting.

0216 PM TORNADO ST LOUIS PARK 44.95N 93.36W05/22/2011 HENNEPIN MN TRAINED SPOTTER DEBRIS CLOUD HIGHWAY 100 AND 394..SURFACE LEVEL ROTATION

Time lapse of the Minneapolis tornado forming from Rich Colombo via NWS Facebook page.

And the damage report after the fact. (Indicates 2:15 pm touchdown)

PRELIMINARY LOCAL STORM REPORT

NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN

1156 PM CDT SUN MAY 22 2011

0215 PM TORNADO MINNEAPOLIS 44.96N 93.27W

05/22/2011 HENNEPIN MN LAW ENFORCEMENT

*** 1 FATAL, 30 INJ *** THE ONE FATALITY OCCURRED AT THE

INTERSECTION OF 37TH AND FREMONT AVENUE NORTH. TWO PERSON

WERE REPORTED CRITICALLY INJURED.12 PEOPLE HAD MODERATE

INJURIES AND 15 HAD MINOR INJURIES.

Home destroyed in North Minneapolis. (NWS photo)

The local NWS did a good job of providing lead time Sunday. Many more lives may have been lost if warnings and sirens were not sounded in advance of the tornado

Joplin tornado nightmare: Deadliest single U.S. tornado in 60 years?

We're still learning about the devastating tornado that tore through Joplin, Missouri Sunday night, but a few things are clear.

This monster looks to have been a mile wide at the base and may have had winds of 200 mph. The devastation in the path is complete.

According to The Weather Channel's Dr. Greg Forbes, this may have been the single deadliest U.S. tornado in 64 years. 2011 looks like the deadliest tornado year since 1953!

Here are some details from weather.com.

"TWC Severe Weather Expert, Dr. Greg Forbes (Find him on Facebook) now says the Joplin, Mo. tornado is the deadliest single U.S. tornado in 64 years, since 181 were killed in Woodward, Okla. on Apr. 9, 1947.

In fact, there have been only 8 tornadoes documented in U.S. history that have claimed more lives than the Joplin, Mo. tornado!"

Top 10 deadliest tornadoes

Mar. 18, 1925 (Tri-State Tornado): 695

May 6, 1840 (Natchez, Miss.): 317

May 27, 1896 (St. Louis, Mo.): 255

Apr. 5, 1936 (Tupelo, Miss.): 216

Apr. 6, 1936 (Gainesville, Ga.): 203

Apr. 9, 1947 (Woodward, Okla.): 181

Apr. 24, 1908 (Amite, La., Purvis, Miss.): 143

Jun. 12, 1899 (New Richmond, Wisc.): 117

May 22, 2011 (Joplin, Mo.): 116

Jun. 8, 1953 (Flint, Mich.): 115

The incredible death toll of 116 late Monday will likely change as searches are still ongoing through the rubble.

NWS storm surveys are ongoing and may take several days in Joplin.

For all the damage in Minneapolis Sunday, we can be thankful our tornado was not as large as the Joplin monster.

PH