Tuesday, April 26, 2011

Turbulent weather system wallops Missouri with rain, floods


By Roger Meissen
Story source: Pat Guinan, 573-882-5908

For podcast with MU Extension climatologist Pat Guinan, click play button:


COLUMBIA, Mo. – Tornadoes in St. Louis and torrents of rain elsewhere led to property damage, flooding and a man’s death in southern Missouri flash floods. These are just part of what a volatile system of storms will bring this week.

“The middle part of the country tends to be a battle zone where dynamic systems clash, so we have those systems moving along the jet stream with instability, moisture, cold air and warm air – all the ingredients for severe storms,” said Pat Guinan, climatologist with the University of Missouri Extension Commercial Agriculture Program.

“With continued heavy rain chances across southern Missouri early this week, major flooding will persist or worsen,” Guinan said. “Significant flooding will also continue along the Mississippi River from Iowa downstream through Missouri.”

The National Weather Service warned on Sunday of dangerous flash-flooding potential in many areas of Missouri, and river systems are running near capacity. The Mississippi River is expected to crest at almost 6 feet above flood stage this week, and flooding on the Missouri River system is traveling downriver from Nebraska.

Forecasts estimate 1-6 inches of precipitation this week for the southern half of Missouri, mostly due to a stalled frontal system hanging over the region. That rain will keep rivers at capacity or out of their banks.
“A contribution to this stormy weather has been an active jet stream sandwiched between contrasting air masses,” Guinan said. “Much of the northern U.S. has seen a colder-than-normal April and much of the southern states have seen much above-normal temperatures.”

These conditions won’t bode well for farmers looking to get seed in the ground.

“Planting opportunities likely will be nonexistent for the rest of April, and this definitely will create some concern for farmers who won’t be able to get into fields for the next several days at least,” Guinan said.

 

Snow impact

Last winter’s snowfall played a part in setting the stage for flooding.

Columbia rounded out the year with its second-highest snowfall on record. At 53.4 inches, the snow came about an inch-and-a-half short of the 1977-78 record. Both St. Louis and Kansas City also received snowfall that ranked in their top 10 snowiest years.

All that snow leads to a lot of water when it all melts, and the spring thaw contributed to current river levels.

“Significant snowpack in the northern Plains and upper Midwest all translated to runoff that’s kept the river systems at above normal and flood level,” Guinan said. “In February, March and here into April we’ve had increased snow and rain, so soils are moist statewide and we’re seeing surplus water resources impacting Missouri both above and below the ground.”

Winter temperatures also ran below normal, causing a second cold winter in a row.

“We haven’t seen two consecutive colder-than-normal winters since the early 1990s,” Guinan said. “It’s somewhat of a reality check because we’ve been spoiled the past two decades with some very mild winters and not much snowfall. The last time Missouri experienced several cold and snowy winters was in the 1970s.”

For more climate information, go to http://climate.missouri.edu.

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