...Heavy Snow and Ice Reported in Much of Northern Missouri and Kansas - February 20-21, 2010...

 

For a review of the seasonal statistics thus far, please visit the "Winter 2009/2010 Preliminary Review Page"

Summary:

Yet another winter storm in an already active winter season impacted much of Kansas and Missouri during the weekend of February 20-21, 2010. This challenging winter storm, more typical of late February, brought numerous forecast problems with hazards ranging from heavy snow, to sleet, ice, rain, and even flooding.  This upper level storm system originated well off the California coast just a few days ago.  Its general track was typical of a classic El Nino pattern moving across the Southwest and lifting northeast into the Missouri and eventually Ohio River Valley regions.  At the surface, several waves of precipitation moved through the area, with periodic sleet, snow and rain showers persisting from late Saturday afternoon through daybreak Sunday.  However, the heaviest precipitation was still to come. 

Late Sunday night, a large area of thunderstorms developed in Texas, Oklahoma, and Kansas and began streaming northeast towards the area.  While thunderstorm activity diminished as precipitation arrived,  heavy rainfall still took place across portions of central Missouri.  As of Monday morning, numerous streams, rivers, and creeks remain at flooding levels.  This precipitation area also produced rapid ice accumulations south of the Missouri river at daybreak Sunday.

However, this was only the beginning of the heavy precipitation.  As an area of surface low pressure and upper level low passed just south of the area, a large but incredibly intense band of snowfall developed in areas of northern Kansas and northern Missouri Sunday morning.  This band of snow persisted through the evening hours of Sunday, producing snowfall rates between 1 and 2 inches per hour at times. Snowfall tapered off by Monday morning as the upper level storm system moved well to the east of the region. 

Upper Level Low Track and Forecast
Surface and Radar Analysis


Complex Storm:

The complexity of this storm system was a stubborn warm layer above the ground in the lower portions of the atmosphere.  Throughout this event, this "warm nose" of air was nearly stationary from Emporia, to Topeka, through Kansas City and further northeast towards Moberly. The images below depict this area very well with the 0 degrees Celsius (32F) line splitting through Kansas City at 6 am Sunday morning.  South of the white line, increasing temperatures and a thickening warm layer above the surface allowed for a multitude of precipitation types.

 
 850 MB Temperatures at 6am Sunday
 Vertical Cross Section of Temperatures in the Atmosphere - 6 am Sunday
 

You might be curious as to why one area may get snow, while another location just a half hour away is receiving freezing rain. The key is in the temperatures within the atmosphere, specifically those between the ground and the clouds aloft. The graphic below illustrates the following explanations of precipitation type.

Snow is produced when temperatures are cold both aloft and at the ground. The snow does not melt as it falls, and temperatures at or below 32 degrees near the ground allow it to accumulate.

Sleet is formed when temperatures at or slightly above freezing aloft produce rain that freezes to ice pellets, as it falls into a cold layer of air. Sleet usually bounces when hitting a surface and does not stick to objects. However, it can produce a “sandlike” accumulation like snow.

Freezing rain forms when warm temperatures aloft, generally several degrees above freezing, produces rain that falls onto a surface with temperatures below 32 degrees. This causes the liquid rain to freeze on impact to objects such as trees, power lines, cars and roads forming a coating or glaze of ice. Even a small amount of freezing rain on roads can create a significant travel hazard.

 


Snowfall and Ice Totals:

The following is a preliminary-estimated snowfall graphic from this winter storm. All-in-all, a very wide band of 6 to 10 inches of snow was observed along a corridor from St. Joseph, MO through Gallatin, Trenton, Chillicothe, Kirksville, and Macon, MO.  Lesser amounts of snow were common north and south of this line.   As anticipated, an extreme gradient of snowfall was present across the transition line.  In Kansas City for example, snowfall in the extreme northern portions of the city was as high as 6 to 8 inches.  However in areas from Lees Summit, to Belton, and Grandview snowfall and sleet amounts were generally around an inch or less.

This snowstorm did break one record as it moved through the area.  A new daily record snowfall of 5.1" was set on the 21st at the Kansas City International Airport.  This breaks the previous record of 3.6" set back in 1997.

Ice accumulations were the heaviest in areas from Kansas City, to Pleasant Hill, Paola, and further east along the Missouri River.  Reported ice accumulations between one quarter and one half inch were common across Kansas City.  Due to surface temperatures holding near 31 and 32 degrees Sunday morning, as freezing rain was moved through, ice accumulation on roadways was minimal.  The heaviest accumulation of ice occurred on trees, power lines, and other elevated surfaces.  In fact, ice accumulations near Blue Springs, MO caused a power outage for a portion of the day.



Click on the image for a larger version
Snowfall Totals for February 20-21, 2010 Metro Snowfall Totals - February 21, 2010

Ice Accumulations for February 20-21, 2010

 


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