Severe Plains

April Tornadoes in Missouri (1950-2011)

// March 30th, 2012 // No Comments » // General Information, Severe Weather, Weather Recap

I promised an April tornado summary for Missouri a couple of days ago when I published the Kansas review, well here it is! Come absorb all of the data…

According to the NCDC (National Climate Data Center) Missouri has averaged 8 tornadoes during the month of April over the past 20 years; if you go back over the past 62 years (1950-2011) you will find that Missouri averages 6.3 tornadoes per year.  Similar to the reason I gave for Kansas is that the further you go back the less likely you were to miss a tornado as it struck in open land and no one witnessed the storm.  Comparatively, there is hardly a tornado that goes missed across the Central Plains and most of the U.S. for that matter in this day and age.  April is the second most active month for tornadoes over the past 20 years, only falling behind May which averages 12 tornadoes.  The 8 tornadoes over the course of April is also good enough to tie for sixth (with Iowa) for most active state.  The graph below shows the number of tornadoes per year during the month of April in Missouri:

You can see that 1994 was the most active April on record with 26 tornadoes, 1973 wasn’t too far behind with 23. Several other years featured a dozen or more tornadoes while there were 10 years where Missouri tallied zero tornadoes during the month.  Digging into the numbers a bit we can say that there is a 16% chance of seeing no tornadoes while there is a an equal 16% chance of seeing more than a dozen tornadoes.  When are tornadoes most likely to occur during the day in April for Missouri?  Well the evening is obviously the ideal time with 56.4% of April tornadoes occurring between 3-7pm (CST).  However, taking a look at the graph below you will see that a tornado has occurred at every hour within Missouri during the month of April!

Over the past 62 years there have been 485 injuries and 19 fatalities caused by tornadoes during the month of April in Missouri.  One of the more damaging tornadoes came on April 2, 2006 when a tornado struck Caruthersville and injuries 130 along with killing 2 while destroying much of the town.  The deadliest tornadoes in April history within Missouri borders occurred on April 24, 1975 when an (E)F4 struck Neosho, the tornado also injured 22 others.  In total there have been 15 deadly tornadoes, with 66 tornadoes causing injury.  Details on three of the tornadoes are below:

There has never been an (E)F5 tornado in Missouri during the month of April, however there has been 14 (E)F4 tornadoes with an increasing amount of weaker tornadoes.  While most tornadoes are rated (E)F0 Missouri actually has had more (E)F1 tornadoes during the month of April than (E)F0.  A complete graph with all of the ratings is below:

April Tornadoes in Kansas (1950-2011)

// March 28th, 2012 // No Comments » // General Information, Severe Weather, Weather Recap

Severe weather season is inching closer with each day, although we’ve already seen episodes of severe weather this year.  I’ve done some research and data mining into the history of tornadoes in April for the state of Kansas (Missouri  you are up next!) and included it below, hope you enjoy:

Over the past 20 years Kansas has averaged approximately 12 tornadoes during the month of April, high enough for third-most in the United States (behind Illinois & Texas).  Take this average back to 1950 and Kansas averages only 7.7 tornadoes per year, this decrease is likely due to the overall decrease in tornado numbers nationwide in years past.  Once again, taking a look back at the previous 20 years we would see that April accounts for one-eighth (12.5%) of all tornadoes that occur in Kansas, making April the third most active month (behind May and June).  That gives us a good overview, now lets dive into some numbers and show off some graphs!

A few details from the graph above, April of 1964 featured the most tornadoes with 46 followed by 1991 (39 tornadoes), 2005 (37 tornadoes), 2001 (35 tornadoes) and 1984 (29 tornadoes).  There have been 12 occurrences where no tornadoes occurred in April, or about 19% of the time there are no April tornadoes.  Last year (2011) there were only 6 tornadoes in April, all of them occurred on April 14.  You can take a look at the graph below to see the time of tornadoes during the month of April, and as expected the evening time frames lead the way for peak tornado time.

There have been 499 injuries as a result of 49 April tornadoes in Kansas, 255 of which occurred with the same tornado, the Andover, KS tornado on April 26, 1991.  The tornado outbreak on that day had 21 total tornadoes including the Andover tornado, in all there were 243 injuries that day and 18 fatalities.  Other dangerous tornado days included April 2-3, 1956 where 9 tornadoes crossed over Kansas and resulted in 45 injuries and 2 fatalities; April 12, 1964 where 5 tornadoes resulted in 34 injuries and 4 fatalities.  You can find a complete list of all deadly tornadoes in April below:

The last graph to view is of the Fujita scale rating for every April tornado in Kansas (1950-2011).  Only one (E)F5 has occurred during the month of April, the deadly Andover, KS tornado.  The count gradually rises as you decrease in intensity, clear down to (E)F0 which account for just under 47% of the tornadoes in April.

Hope you’ve enjoyed the data and details, look for another update on Missouri tornadoes in April and a monthly review of March in the coming week(s)!

Record Breaking Temperatures

// March 12th, 2012 // No Comments » // General Forecast, General Information, Weather Recap

A very abnormal week is expected ahead for nearly the entire Central & Eastern United States as very warm and climatologically moist air builds northward and parks itself over the regions. Take a look at the Climate Prediction Center’s forecast (MOS) mean temperature anomaly for Monday-Friday of this week! That’s right, mean temperatures over 20 degrees above normal for mid-March over the Northern Plains and 15-24 degrees above normal for the Central Plains.

These abnormally high temperatures will likely mean record breaking temperatures for many areas, and not just for a day or two but rather multiple consecutive days where the record high temperatures will be in jeopardy. Another temperature record that will likely be in jeopardy is the record high minimum, essentially the warmest low temperature for each day. I’ve selected a few cities across the Central/Northern Plains to keep an eye on this week and will update this post when possible with the actual temperatures for the day to see how many records fell in these select cities (I’m sure there will be plenty of other cities breaking records as well). Note, forecast temperatures were as of Sunday afternoon from respective NWS WFO’s.

February Tornadoes – Nebraska, Kansas & Missouri

// March 10th, 2012 // No Comments » // Severe Weather, Weather Recap

I realize we are well out of the month of February and in reality pushing into the middle of March, but thought it would be pertinent to go back and take a look at those February tornadoes that occurred across the local region and the history of tornadoes during February in the selected states. As you may realize, I like statistics and facts so this will give out a few of those along the way…

A look back at Nebraska‘s February tornadoes will not take long, as the EF-0 tornado that occurred on February 28, 2012 is the first and only tornado to have occurred in Nebraska during the month of February!  According to the North Platte WFO the confirmed tornado occurred 9 miles west-southwest of Gandy, Nebraska (or 21 miles northeast of North Platte, NE) at approximately 4:13pm.  It was on the ground intermittently for up to six minutes as it traveled nearly 3 miles while it moved to the northeast.  The tornado occurred over range and cropland, therefore only inflicting minor damage.  A radar image courtesy of North Platte WFO & a photo from local Bob Denny is below:

Kansas had recorded 19 tornadoes during the month of February before 2012, including an EF-4 that occurred on February 28, 2007 over Anderson and Linn Counties.  However, there had been only 1 injury with these previous February tornadoes and no fatalities.  The small outbreak of severe weather that occurred on February 28, 2012 across eastern Kansas resulted in 5 tornadoes (1 EF-2 & 4 EF-0) which ends up being the second largest February outbreak of tornadoes, only behind February 28, 2007 when 6 tornadoes occurred.  Unfortunately, the EF-2 tornado that quickly developed and moved through Harveyville, KS resulted in the first February death from a tornado in Kansas and injured an additional 11 people.  There have been multiple stories on this lone tornado concerned the lack of tornado warning when it struck the town, here is the summary from the Topeka WFO which features additional pictures, radar scans and the survey:  Harveyville, KS EF-2.

It isn’t that uncommon for Missouri to see tornadoes in February, in fact they ranked 9th in February tornadoes by state from 1950-2011 with 62 tornadoes per SPC Archives. The state is also unfortunately accustomed to injuries and fatalities due to tornadoes during the month. Missouri has had 28 people killed and 409 injuries by tornadoes, although 21 fatalities and 345 injuries came from a single tornado that moved through the St. Louis Metro on February 10, 1959. 10 more tornadoes were added to the totals on February 28-29, 2012 as storms rolled across southern Missouri, killing 3 and injuring another 41 people. Missouri unofficially now stands at 31 people killed and 450 injured during the month of February from tornadoes. The Branson, MO tornado received the great media attention from this month as it struck the popular tourist destination near 1am.

February 28-29 Tornadoes

// March 1st, 2012 // 1 Comment » // Severe Weather, Weather Recap

A strong storm system with unseasonably warm and moist air moved across the Central Plains, Midwest and other areas on Tuesday and Wednesday producing widespread and significant severe weather.  The first watches and warnings were issued Wednesday afternoon for Nebraska and Kansas, with the severe weather threat later expanding over central/eastern Kansas and then into Missouri and parts of Oklahoma and Arkansas late Tuesday night.  As the storm system continued early Wednesday morning the threat quickly spread eastward, through southern Illinois and across Kentucky along with adjacent areas of northern Tennessee & far southern Indiana.  The threat wouldn’t stop there either, continuing through Wednesday afternoon over portions of the Southeast and into the western fringes of the Carolina’s.

Over the course of this outbreak the Storm Prediction Center issued 15 tornado watches and local National Weather Service offices tallied 328 warnings, 129 tornado and 199 severe thunderstorm from 3pm CST on February 28 to 3am EST on March 1.

Several damaging and unfortunately deadly tornadoes occurred both Tuesday and Wednesday, damage photos have been circulating throughout the past 24 hours in areas like Harveyville, KS; Branson, MO; Harrisburg, IL and more.  The table below has been updated multiple times since the original post to include additional tornadoes that NWS damage surveys have found.  I’ve now included a quick tally of tornadoes and details just ahead of the table.

Total Tornadoes -28
EF4 – 1
EF3 – 1
EF2 – 11
EF1 – 10
EF0 – 5

Fatalities – 13
Injured – 172 (approx)

Updated at 11:40am to include recent death of Harveyville, KS tornado victim.
Updated at 12:36pm to include Cassville, MO tornado details which included 1 death & 4 injuries (EF2).
Updated 12:44pm to include details on Dade & Polk Counties (MO) EF1 tornado.
Updated 4:12pm to include Tennessee tornadoes & 2 additional Missouri tornado (Phelps & Dent Cnty + Stoddard).
Updated to include EF1 tornado in Barton County (MO).

The information above is preliminary and may change, however this should provide a good overview on the tornadoes that occurred in the Central Plains and Midwest over the past 48 hours.  If you find any information that you would like for me to change, please let me know by either using the Contact page or send me a Tweet @SeverePlains.

A few extra notes, if you want to see all of the storm reports from the past two days you can view them on the SPC Storm Reports Pages (February 28 – February 29) or use the Interactive LSR App on Iowa Environmental Mesonet.  Also, wanted to throw in this very neat image put together by Cory Mottice.

Meteorological Winter Ending

// February 29th, 2012 // No Comments » // General Information, Weather Recap, Winter Weather

A strong storm system has produced several damaging tornadoes that have resulted in multiple deaths and injuries across parts of Kansas, Missouri, Illinois and now into the Kentucky and other nearby areas.  I will likely have an update on all of the severe weather over the past 24 hours at a later time when damage surveys and official numbers have been confirmed…

Thanks to the leap year we get one extra day of meteorological winter this year (compared to the past 3 years).  This won’t help anyone in Kansas or Missouri with their winter snowfall, but it is helping some across the Dakotas, Minnesota, Wisconsin and other nearby areas along with areas of the Great Lakes & Northeast.  The meteorological winter is going to come to an end in Kansas City with only 3.1″ of snow which will rank as the 5th lowest snowfall on record (2.2″ occurred in 1991-92).  In the previous post I posted a ratio that I calculated, inches of snow per inch of liquid precipitation, in an attempt to show years in which we’ve still had precipitation but just a lack of snow.

Kansas City has added on 1.30″ of liquid precipitation since that last update while only seeing a few flurries, pushing the liquid precipitation for the meteorological winter to 6.22″ while leaving snowfall at the 3.1″ as mentioned above.  What does this do to the ratio, it dropped from 0.6301 to 0.4984 – Essentially per liquid inch of precipitation this winter Kansas City saw less than a half inch of snow.  My previous post included the detail that the average ratio for all 123 years of record in Kansas City was 3.83.  The drop to 0.4984 didn’t change the ranking that the 2011-12 season had (it’s still 3rd) but it is much closer.

For some details, we can take a look at the 5 least snowiest meteorological winters in Kansas City and see how their ratios’ compare:

Comparing the 5 least snowiest seasons you can see that 2 of the 5 had a lack of precipitation to go along with the lack of snowfall, 1919-20 & 1022-23 had correlations that were well above 2 and therefore not an extreme anomaly compared to the average.  These two seasons simply had a lack of precipitation overall.  The other two seasons are ranked first and second ahead of this latest season in their correlation, with precipitation still occurring across the area but just a plain lack of snowfall similar (or actually worse) than this year.

This ends another math filled and interesting perspective on the winter (or lack thereof) in Kansas City!

Winter Snowfall vs Precipitation

// February 22nd, 2012 // No Comments » // General Information, Winter Weather

Snowfall has definitely been lacking for many areas of the United States this year, with cities running well below average for snowfall to go along with near-record warmth. But, have these cities been looking at a lack of snowfall due to a complete lack of precipitation? I chose a few cities that have been lacking on snowfall and compared their overall precipitation to see if its’ just been dry, or just not cold enough. Then, dug deep into the data for Kansas City to see how snowfall and precipitation compare for this winter and winters’ past.

First, a look at how this years’ lack of snowfall compared to overall precipitation for the meteorological winter season (December-February):

Looking through the data above you can see that many areas are not lacking on precipitation for the winter months, although there are areas that are below normal across the board (Springfield, M and Twin Cities, MN).  You can make the argument that the cold air has simply not been in place when precipitation has arrived this winter, for example, Topeka is well above average for precipitation during this winter however they are well below normal when it comes to snowfall.  A similar case can be made for Kansas City, Columbia, St. Louis and even Chicago for that matter.

I took this one step further for Kansas City, creating a correlation between winter season snowfall and winter season precipitation (Inches of snowfall per Inches of Precipitation) that would roughly show if a season is lacking precipitation & snowfall, just lacking snowfall or had plenty of snowfall and precipitation.  Data was available for the Kansas City area from this season (2011-12) all the way back to the winter season of 1889-90. The average for all 123 seasons was 14.83″ of snow and 4.17″ of precipitation for a correlation of 3.83, which essentially means for every 1″ of liquid precipitation the average winter season has 3.83″ of snowfall.  Here are the past 10 seasons:

Now that you see all of the numbers, what do they mean?  The past two seasons’ correlations were nearly 3 times larger than normal (3.83) which shows that more precipitation was falling as snow than what we would normally expect during the winter season.  This correlation number is backed up when looking at the raw snowfall and precipitation numbers, while snowfall was much higher than normal the precipitation values were not, therefore giving us the higher correlation.  This is also true for the inverse, both this season and 2004-05 had low correlations indicating that while we still had normal (or above normal) precipitation values there was not as much of this falling as now as what is typical.  So how do the correlations rank, which season was snowiest compared to precipitation and what season got the least amount of snow out of the most precipitation?  Well, the past two seasons actually feature the highest correlations which indicates that we squeezed the most snow per inch of precipitation than any other season in history!  But, to look at this season we are going to have to look at which seasons’ produced the least amount of snow per inch of precipitation:

Least Snowfall per Inch of Precipitation

1) 1930-31  -  0.1818 (0.5″ of Snow with 2.75″ of Precip)
2) 1991-92  -  0.4151 (2.2″ of Snow with 5.30″ of Precip)
3) 2011-12  -  0.6301 (3.1″ of Snow with 4.92″ of Precip)
4) 1994-95  -  0.9934 (4.5″ of Snow with 4.53″ of Precip)
5) 2004-05  -  1.2311 (6.5″ of Snow with 5.28″ of Precip)

The correlation for this year can still get lower, or higher, depending upon how much precipitation we can add without adding to our snowfall.  Hope you enjoyed this math-filled post relating snowfall and precipitation…

Strong Thunderstorms (Feb. 20, 2012)

// February 21st, 2012 // No Comments » // Severe Weather, Weather Recap

Strong to severe thunderstorms rolled through parts of Oklahoma, Kansas and Missouri yesterday afternoon and evening producing marginally severe hail over parts of Oklahoma and central Kansas as well as wind damage throughout those 3 states.  Unfortunately, damaging winds flipped over a mobile home to the east of Ada, OK where 1 woman died. Check out all of the strong to severe reports on the image below (click image to view details on reports):

Wind gusts were the primary threat as these thunderstorms rolled across the Kansas City Metro last evening, although some small graupel was mixed in with the rain as well.  Note, I call this graupel rather than hail as the ice falling was not hard, rather as it would hit windows or other objects it would essentially melt or fall apart on contact.  I took a quick snapshot with my phone as this disintegrating graupel built up on the windows.

Wind gusts across the Metro were as follows:

KCI Airport – 54 mph
Olathe, KS (KOJC) – 52 mph
Olathe, KS (Public) – 50 mph
Lee’s Summit – 45 mph
Gardner, KS – 41 mph
Downtown KC – 41 mph

Kansas City Snowfall Records Update

// February 14th, 2012 // No Comments » // General Information, Winter Weather

Kansas City International Airport officially reported 2.4″ of snow on February 13, 2012 after only accumulating 0.7″ of snow for the season previously.  This marks February 13, 2012 as the date the 2011-2012 season officially exceeded the 1″ of snow for the season and the date of the first 1″ snowfall event for the city.  Here’s a final summary of where this ranks all-time:

Latest Date of 1″ of Accumulation for Season

1) 1930-31  -  March 1
2) 2011-12  -  February 13
3) 1933-34  -  February 11
4) 1922-23  -  February 10
5) 1988-89  -  February 4

Latest Date for First 1″ Snowfall

1) 1930-31  -  March 6
2) 1933-34  -  February 24
3) 1910-11  -  February 18
4) 2011-12  -  February 13
5) 1922-23  -  February 10

Another record we can also watch is the least snowiest season on record, here are the top 10 least snowiest seasons for Kansas City:

Least Snowiest Season

1) 1922-23:  4.5″
2) 1949-50:  5.5″
3) 1988-89:  6.9″
3) 1994-95:  6.9″
5) 1933-34:  7.2″
6) 1920-21:  7.3″
7) 1950-51:  8.0″
8) 2001-02:  8.6″
8) 1907-08:  8.6″
10) 2002-03:  9.4″

2011-12:  3.1″ through February 13

Winter Storm: Feb. 12-14

// February 14th, 2012 // No Comments » // Weather Recap, Winter Weather

One of the biggest winter storms of the season for areas of Kansas and Missouri, although by most standards just a general good snowfall over the region.  Snowfall occurred in two general areas, one over Nebraska and Iowa where the heaviest snowfall occurred and another over a more progressive snow across Kansas and Missouri.  A general long-duration moderate snow to the north of the upper level disturbance was the culprit for as much as 6.2″ of snow in Sioux City, Iowa.  Other nearby amounts included 5″ in Spencer, Cherokee and Emmetsburg in Iowa; 4″ in Holstein (IA) and lesser amounts for Des Moines (~1.5″) and Omaha (~1″).

A more progressive swath of snow occurred over areas of Kansas and Missouri, with occasional bands of moderate to even heavy snow at times.  Snow mainly occurred over eastern Kansas, along and east of I-135/Highway 81 with much higher amounts to the south.  The Wichita, KS area was brought to a halt by moderate snow Sunday night when it accumulated rapidly on all surfaces, causing multiple accidents and nearly shutting down Kellogg Avenue.  The Kansas City area saw snow develop shortly after Midnight and continue into the Monday morning rush hour, generally 1.5-2.5″ of snow fell across the KC Metro.  Slightly heavier snow fell over parts of southwest Missouri, into central and east-central Missouri where 2-4″ was reported including 2.7″ in Columbia and 2.5″ in Jefferson City.  The St. Louis Metro took on moderate to occasionally moderate snow during the evening rush hour on Monday, when snowfall rates were in the 1-2″ per hour.  Total snowfall amounts typically were between 1.5-2.5″ for most of the St. Louis Metro.

Other than the snowfall, prolonged areas of drizzle and freezing drizzle were also prevalent with this storm system that cause some additional issues for some.  In Gardner (my house) we measured up 1.6″ of snow with the event with a nice glaze of freezing drizzle during the day on Monday to create a crust on the snowfall.

The snowfall won’t last long for many with temperature already rising into the 40s today over Kansas and Missouri, then the next storm system moving in on Wednesday that will bring rain and maybe even a rumble of thunder or two to some areas.  Some light snow is possible with this system as well, but nothing too significant at this point is expected.

If you want to take a look at all of the snowfall reports from the past 48 hours over Kansas, Nebraska, Missouri and Iowa check out the link here:  Local Storm Report App