Minnesota tornado facts

In conclusion of Severe Weather Awareness Week across Minnesota, here are some facts when it comes to tornadoes in the state:

• Minnesota’s first recorded tornado in history occurred on April 18, 1820 at a camp that eventually became Fort Snelling.
  
• There has not been an EF-5 tornado in Minnesota since the Enhanced Fujita scale started February 1, 2007.  The last F-5 tornado in the state was on June 16, 1992, affecting the City of Chandler.
  
• Minnesota led the nation in tornadoes with 113 in 2010. 48 of those occurred June 17 as part of largest known outbreak in state history.
  
• 31 tornadoes were reported in Minnesota during 2011. Three of those were rated EF-2, the strongest of the year.
  
• Since the Enhanced Fujita scale became operational, there have been 229 tornadoes in the state through 2011.   The percentages are as follows: 59% EF-0, 29% EF-1, 7% EF-2, 3% EF-3, 2% EF-4.

RS

How do you primarily receive weather alerts?

I posed this question on my weather-related Twitter and Facebook accounts to get an idea of how others receive weather alert information.  Here are Twitter responses:

@ckostik: Phone Text message

@RickyMorgan71: Your tweets.

@OSNW3: Nothing automated, I usually know of the situation ahead of time and keep tabs by using the Internet.

@JakeWhiting: I use WeatherBug, Simple Weather Alerts (for Android), and Twitter. One is bound to be on time!

@SwishaJames: NWS website from my phone

@tcollen: ESP :)

@DysonGuy: if on computer weatherbug or interwarn. iPhone / iPad I get text alerts and use WeatherRadio app. Weather radio also

@lars21: Weather Channel app on my phone or NWS site if at home

@GingerFritzie: NOAA Weather Radio for the iPhone.

@MayorTabke: MyWeather on the iPhone

There was one constant I saw: No one said the outdoor sirens!  People are using alternative sources for real-time information.  Thanks to everyone who participated in this unscientific poll.

Weren’t able to chime in with a response?  Feel free to share your methods for receiving alerts in the comment section below.

RS

Severe Weather Awareness Week

This week (April 16-20) is Severe Weather Awareness Week in Minnesota.  According to Minnesota Department of Public Safety’s Homeland Security and Emergency Management, “The Severe Weather Awareness Week campaign helps teach Minnesotans about weather hazards and provides resources to minimize the risks associated with severe weather.”  In the past 10 years, more than 40 people have died and dozens more injured as a result of weather-related events in Minnesota (not including motor vehicles).  This blog post will present an overview on what to expect this week as part of Severe Weather Awareness, explain terminology used in weather alerts, and provide alternative methods to traditional media sources for receiving these alerts to stay safe during severe weather.

On Thursday, April 19th, sirens will sound twice as part of a simulated tornado warning.  Once at 1:45 PM, and again at 6:55 PM (all Minnesota counties in the evening except: Aitkin, Becker, Carlton, Hubbard, Itasca, Kanabec, Kittson, Lincoln, Norman, Otter Tail, and Yellow Medicine).  This will provide an opportunity to review action plans at work, school, and home in the event of a natural disaster, such as a tornado.  Sirens will sound for about three minutes.  When the sirens are activated, NOAA Weather Radios will sound an alert tone for a tornado warning.

So what does a watch and warning mean?  A watch means weather conditions are favorable for dangerous weather to occur.  In other words, a "watch" means watch out for what the weather could do, and be ready to act accordingly.  You may wish to alter or have a “Plan B” for any outdoor activities or travel.  A warning means the weather event is imminent or occurring somewhere in the defined warning area and that people need to take shelter as soon as possible.  In 2010, Minnesota had the most tornadoes of any state in the United States with 113.  Tornadoes can occur any time of day or night, but often occur in the late afternoon or evening.  A tornado watch is issued by the National Weather Service when weather conditions are favorable for tornadoes and persons should remain alert for approaching storms.  A tornado warning is issued when a tornado has been sighted or indicated by weather radar.  Take shelter immediately!  Whether a tornado has been radar indicated or confirmed, people should NOT be outdoors looking for the tornado.  There’s a chance it’s already on your doorstep, and by then it’s too late to take cover - leading to injury or possibly death!

How can I stay alert of the latest weather conditions?  I always believe that everyone should have two sources for receiving weather alerts other than outdoor sirens.  An outdoor siren was NOT designed to be heard indoors, and it should NOT be your primary means of warning to take shelter.  Counties and cities own the sirens and therefore decide how and when to activate them, not the National Weather Service.  All sirens are not the same.  There are many different policies by counties and cities.  Some will activate them across the entire county for a tornado warning only.  Others will activate sirens countywide for tornado warnings and all severe thunderstorm warnings.  Some will activate sirens across the entire county for tornado warnings and severe thunderstorms that have winds of at least 70 or 75 MPH, while others will activate sirens only for portions of counties.  Also, local officials may sound the sirens anytime they believe severe weather is a threat, even if there is no warning from the National Weather Service.  In the Twin Cities, Dakota County activates the sirens for any severe thunderstorm warning as well.  A severe thunderstorm warning is issued when thunderstorm winds are indicated or measured to be 58 MPH or greater, and/or contain hail at least one-inch in diameter.  Scott County will typically activate outdoor warning sirens if a tornado warning is issued, according to Chris Weldon, Scott County Emergency Management Director.

Quite frankly, every home should have a NOAA Weather Radio.  They are as essential as smoke detectors in homes.  This is potentially a life-saving device.  The alert technology has been around well before the Internet boom and cell phones, but with enhancements along the way.  Depending on the features, these radios cost anywhere between $20 to $200.  Most brick and mortar retail stores carry these radios (RadioShack tends to have the largest selection), and can also be purchased from online retailers, such as Amazon, using keyword search “weather radio”.  These radios with battery backup are designed to be loud enough to wake you up during a severe weather emergency in the middle of the night, and programmable to broadcast the alert text from the weather service.  Radios with SAME (Specific Alert Message Encoding) technology allow the weather radio to broadcast alerts only for counties you specify using a six-digit code number.  SAME codes can be found here.  It is recommended to select a weather radio with the “Public Alert” certification.  These radio have met certain technical standards and come with many essential features.

There are dozens of radio transmitters covering Minnesota for receiving weather broadcasts.  NOAA weather Radio broadcasts on seven different frequencies, which are pre-configured in most radios as channels.  Nearly every location in the state should receive a good signal.  The one exception is north of Bemidji in Beltrami County near Red Lake.

With the increase in usage of smartphones, apps are becoming more sophisticated.  For iPhone users, iMap Weather Radio is a highly recommended app to alert of approaching hazardous weather for any location using GPS tracking.  When an alert is received, a loud “chirp” tone will sound, and type of alert will be announced.  More details can be found in a review I did here.  According to app maker Weather Decision Technologies, an Android version is currently in development.

Speaking of phones, CellWarn from Convective Development sends weather watches, warnings, and advisories to your email and/or cell phone for free (carrier text message rates may apply).  The free service includes delivery options such as severe thunderstorm watches and warnings, tornado watches and warnings, winter watches, warnings, and advisories, and severe thunderstorm outlooks.

Social media is also a great way to stay informed.  My weather-related Twitter account, @ShakopeeWeather, and Facebook page post warnings for Minnesota as they come in from the National Weather Service.  Other accounts such as @iembot_mpx, posts all Twin Cities National Weather Service products, and @severewarn, posts warnings issued anywhere in the United States.  From my experience, most meteorologists are active on these social media sites during severe weather events, and are prompt with posting weather information pertaining to a dangerous situation.

As we get deeper into the severe weather season across Minnesota, I encourage the general public to start preparing this week for the thunderstorm season by establishing access to alert services and understanding the different weather alerts issued by the National Weather Service.  It will help eliminate any confusion during an actual emergency.  If you would like to get involved as a storm spotter in Minnesota (there are never enough), class schedules are posted here for outstate residents, and here for Twin Cities residents.

Additional information for Severe Weather Awareness Week:

• National Weather Service – Twin Cities
• Minnesota Department of Public Safety - Homeland Security and Emergency Management

RS

04.15.12 McLeod County, MN

My first real storm chase of the year.  Severe thunderstorms were expected on Sunday, April 15th, as warm, moist air was to surge northward out ahead of a cold front and behind a warm front lifting through south-central Minnesota.

The Storm Prediction Center was confident that a severe weather event would take place that it issued a moderate risk of severe thunderstorms Sunday morning across southeastern Minnesota, as well as portions of Wisconsin, and Iowa.

Wind shear profile were favorable for the development of tornadoes, some of which could have been strong.

From the SPC forecast discussion:

CURRENT THINKING IS THAT THE GREATEST SEVERE CERTAINTY/POTENTIAL CONCENTRATION WILL BE TO THE EAST-NORTHEAST OF THE NORTHEASTWARD ADVANCING SURFACE LOW NEAR WHERE IT INTERSECTS THE WARM FRONT/ADJACENT WARM SECTOR...WITH POSSIBLE OUTFLOW AUGMENTATION AS WELL. ROBUST DEEP LAYER WIND FIELDS...WITH STRONG/ELONGATED LOW LEVEL HODOGRAPHS AND VERY DEEP LAYER SHEAR EASILY ON THE ORDER OF 50+ KT...WILL LIKELY SUPPORT AN INITIAL SEMI-DISCRETE MODE OF FAST NORTHEASTWARD-MOVING SUPERCELLS WITH AN EVOLUTION TO FAST LINE SEGMENTS/BOWS. ACCORDINGLY...ALL SEVERE HAZARDS APPEARS POSSIBLE...INCLUDING THE POSSIBILITY OF TORNADOES...SEVERE HAIL...IN ADDITION TO POSSIBLE SWATHS OF WIND DAMAGE BY LATE AFTERNOON INTO EVENING ACROSS THE UPPER MS VALLEY. TORNADO POTENTIAL /PERHAPS A FEW STRONG/ WILL LIKELY BE HEIGHTENED NEAR/NORTHEAST OF THE SURFACE LOW AND WARM FRONT/PERHAPS RESIDUAL EARLY DAY OUTFLOW.

Morning cloudiness really hindered the ability to get a full day of heating to create enough instability for thunderstorms.  This was the concern I had all day, and putting me on the fence as to whether I was going to go out and chase.  Another problem I eventually saw was that winds were out of the south-southeast instead of the south, which prevented the really rich Gulf moisture from getting here.  Dew points at the height of the severe weather were in the low 60s and relative humidity levels in the 60 to 70 percent range outside of the thunderstorms.  Good, but not terribly impressive.

By afternoon, some clearing was able to take place and the sun broke through.  At 3:40 PM, a tornado watch was issued for a good portion of southern Minnesota, with thunderstorm activity expected to develop over southwestern Minnesota and spread east throughout the day.

More storms fired during the afternoon and moved north.  Despite thinking this setup didn’t have much promise even with a moderate risk and tornado watch, I decided to head west from Eden Prairie and make a play on storms traveling through McLeod County near Glencoe.

As I was heading towards Glencoe on US-212 from the east, I saw this nice cloud formation with an inflow tail on the south side of the highway.  It lasted a couple minutes and then dissipated.  Perhaps it was the most interesting feature I saw on the whole chase.  It may be difficult to see in the video below.  All I had going was a low-res streaming dash cam.

As I passed Glencoe, an interesting hook echo appeared on radar just south of the town of Biscay around 5:20 PM.  I got north on Minnesota State Highway 22 to get on the storm, but found myself about 5 miles out (as the crow flies) from town when a tornado was reported at 5:24 PM, which is when this radar image scan below was taken. Noted is my position as recorded by Spotter Network at 5:24 PM.

AT 524 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO. THIS TORNADO WAS LOCATED NEAR BISCAY...OR 7 MILES SOUTHEAST OF HUTCHINSON...MOVING NORTH AT 45 MPH.

I headed north from Biscay on McLeod County Road 4 in hopes of catching a glimpse of the twister to my east over open country, but alas, no dice.

I ran into Minnesota State Highway 7 and headed back east.  On Highway 7, I took Carver County Road 30 into New Germany, and eventually Mayer.  Saw a lot of low topped clouds with rain on this trip, and not a whole lot of lightning.  Between New Germany and Mayer, I ran into a sheet of heavy rain and pea size hail.  The intensity of the storms dwindled as I patronized Carver County, so I decided to call it a day until I bit on some redeveloping storms over Eden Prairie.  I decided to chase those until north of the Interstate 494/US-169 intersection into Edina on US-169 before turning around and finally calling it a day.  By then, the tornado watch box was being dropped from west to east pretty quickly.  Most of the Twin Cities was out of the watch box by 8 PM or so, if I recall correctly.

For an elevated risk of severe thunderstorms this day, there was not a lot of severe weather to be found.  There were just too many things working against severe storm development.  I felt a little letdown, but going in I wasn’t expecting too much this day.  My April chases haven’t been much luck anyway.  This wasn’t the most photogenetic chase, as I didn’t even get out of the car at all to snap photos, which is unusual for me during the daytime.  It would have been nice to see a tornado over open country, in an unpopulated area.  For the Twin Cities sake, I’m glad nothing happened here.

There were just three tornado reports, and a report of one-inch size hail in Glencoe.  A couple funnel clouds reports thrown into the mix as well.  Fortunately, the tornadoes occurred over open land, and no injuries or damage was reported.

Using my Spotter Network location tracking log, here is where I traveled on this chase:

 “To infinity and beyond!”

Total severe reports: 0

RS

Severe weather outbreak for metro and areas southeast today?

A possible severe thunderstorm situation is setting up for the central part of the United States today, including southern Minnesota.  Below is the area I depicted where the greatest threat of severe storms will be found today.

The Storm Prediction Center in it’s morning outlook placed much of southeastern Minnesota under a moderate risk (an elevated risk if you will) of severe thunderstorms, which includes the Twin Cities, Mankato, and Rochester.

Illustrated below is where the greatest tornado threat exists according to the Storm Prediction Center. The purple area is where a greater than 15 percent chance exist for tornadoes.

I’m still favor the Wisconsin side of the border for tornadoes today….Menomonie, Eau Claire, and La Crosse.

Bust potential.  The big question with today’s setup is whether we will get out of the clouds and receive the necessary daytime heating for thunderstorm development.  Some clearing is trying to take place across southern Minnesota, near the Iowa border.  If we are in the clouds all day, severe weather will be rather limited.  The tornadoes that have hit Minneapolis over the last several years proves you don’t need an ideal setup for tornadoes to form.

Keep an eye to the sky today!

RS

Good chance of severe weather across southern Minnesota this weekend

As an update from my previous post yesterday, the warm front that is one of the drivers for the severe weather outbreak expected this weekend across the U.S. Heartland, will move northward Saturday night and settle over the middle half of Minnesota on Sunday as an area of low pressure navigates towards the area.  This shift will raise temperatures well into the 70s behind the front, and along with it, transport humid, tropical Gulf moisture with dew points into the 60s.

Early Sunday morning, the air mass is forecasted to become moderately unstable as CAPE values reach 2000 J/kg.

Bulk wind shear values in excess of 60 knots from the surface to 500 millibars will more than support a severe weather event.

With this kind of wind velocity, my worst fears are being confirmed.  There will be an overnight tornado threat going into the day Sunday.  Below is a “tornado index” between 1 a.m. and 1 p.m. Sunday.  Make sure to have your NOAA Weather Radio ready and the alert function turned on.  If you are an iPhone user, now is the time to have iMap Weather Radio installed!

In the Upper Midwest, here is where the greatest threat for severe thunderstorms will be found during the mid-morning on Sunday.  All modes of severe weather will be possible – large hail, damaging winds, and tornadoes.

Follow www.stormchaserschwartz.com all weekend long for additional updates!

RS

Severe potential this weekend

A potentially explosive severe weather situation is setting up over the Central Plains this weekend as a low pressure area, with associated warm front and dry line, set up east of the Rockies on Saturday.

A moist, unstable air mass is forecasted behind the warm front and out ahead of the dry line.

Strong south winds at the surface turning more westerly with height will help create enough shear in the atmosphere for rotating supercells.  These supercells will be capable of producing tornadoes, perhaps large and destructive ones.  In addition, large hail and damaging winds can be expected.

Winds at 850 millibars (~5,000 feet):

Winds at 500 millibars (~18,000 feet):

The area where I see the greatest threat for severe thunderstorms, including tornadoes, is over eastern Nebraska and western Iowa.  If I wasn’t going to a Twins game Saturday at Target Field, I would consider the Sioux City, Iowa area as an initial chase target.

As for Minnesota, it will all depend on where the warm front lines up.  If the models move it further north over the next day, then the chance for severe thunderstorms increases in the area.  Right now, the bulk of the heaviest weather should stay south of the Interstate 90 corridor.  Any strong storms that develop north of the warm front in an elevated environment will be capable of hail and gusty winds.

RS