...Another Round of Heavy Rain Plagues the Center of the Country...
September 11-14, 2008

 

A second round of heavy rain and flooding affected the area during the second week of September.  In a setup very similar to that experienced at the beginning of the month, the center of the country fell under the influences of two tropical systems which initially affected other portions of the country.  The first tropical influence to the region arrived by the afternoon hours of September 11th.  Former tropical storm Lowell slowly limped onto the northwestern portions of Mexico late on September 11th.  As you can see on the animated map below, at the same time a strong upper level disturbance edged a cold front into northwestern Missouri.  As this front stalled out across the area, copious amounts of moisture streamed northeast ahead of this front on the 11th and out of the southwest United States.

Click on the Image for a Larger Animation

Animation of Surface Features from September 11-14, 2008

 

This tropical moisture plume interacted with several embedded disturbances moving along the front to produce several rounds of shower and thunderstorm activity from the evening of the 11th through the 13th.  What made this heavy rain event even more unique was the relatively high moisture values observed in the atmosphere.  At one point, upper air soundings out of Topeka, KS during the evening of the 12th indicated precipitable water values (a measure of the water content in the atmosphere) as high as 2.20 inches. Climatologically speaking, the water content in the atmosphere during the 12th and the 13th averaged some 2 standard deviations above normal and were nearly at the highest levels ever recorded for this time of year.

While heavy rain may have caused the most problems, Friday afternoon and evening proved to be just as active as any other stretch of weather lately.  While the bulk of the heavy rain had shifted into northern Missouri, an area of low pressure formed over central Kansas, extending a warm front through central Missouri.  South of this front, temperatures soared into the 80s and even 90s in some locations.  All of this heat and instability allowed for the creation of very small but intense supercell development.  These supercells produced several tornadoes with EF0 damage reported in different locations.  For more information on the tornadic portions of this event, please visit our accompanying web story at:  http://www.crh.noaa.gov/eax/?n=severe_sept122008

By Saturday, the region was slowly transitioning from the exit of the remnants of Lowell and preparing for the arrival of Hurricane Ike which pushed onshore near Galvaston, TX.  This hurricane was poised to make a rather fast and powerful impact onto the region as it quickly tracked from Texas, through Arkansas and into the Ohio River Valley.  After already receiving upwards of 2 to 4 inches of rain from the remnants of Lowell, repeated persistant tropical downpours added an additional 2 to 4 inches of rain to portions of the area.  In addition, strong winds associated with Ike pushed into southern and eastern Missouri, with reports of wind damage stretching from Springfield to St. Louis with wind gusts up to 60 knots reported.

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National 72 Hour Total Rainfall Ending 12 AM Sept 15th

Regional 72 Hour Total Rainfall Ending 12 AM Sept 15th

The images above represent the estimated 72 hour rainfall total (derived from radar and quality controlled and adjusted by observations) ending during the overnight hours of the 14th.  One can see the widespread areas which were affected by this rain event, and primarily from the remnants of tropical storm Lowell.  Many locations from Wichita to Chicago received upwards of 4 to 7 inches of rain.  You can also derive the track of Hurricane Ike as it landed in Texas and then lifted northeast through the country.  While the remnants of Ike produced copious amounts of rain, the relative quick movement of this system spared the country from even more extensive flooding and heavy rain.

A Few Rainfall Totals From the Area:

Kansas City 4.99"
St. Joseph 3.31"
Kirksville 5.98"
Sedalia 5.53"
Chillicothe 4.29
Olathe, KS (OJC) 4.03"
Olathe, KS (IXD) 4.90"
Bethany 4.20"
Clinton 6.51
Albany 4.20"
Carrollton 4.24"
Paola, KS 4.43"
Lees Summit 4.07"
Downing 6.93"
Pleasant Hill 4.44"

 


 ...A Brief Look at History...

 

So where does all this rain put us in the all time September rankings?  Well, with a total of 8.84 inches of rain through the 14th of September, if the month ended now this would be the 4th wettest September of all time for Kansas City (records dating back to 1888).  Our average precipitation for the month is 4.27 inches meaning we are already 4.57 inches above the normal amount for the entire month. If you look at totals through the remainder of the month (given we receive no additional rainfall this month) we will be at least guaranteed of the 10th wettest September ever recorded. 

Highest Total Precipitation inches
Days: 9/1 - 914
Length of period: 14 days
Years: 1888-2008
Highest Total Precipitation inches
Days: 9/1 - 9/29
Length of period: 29 days
Years: 1850-2008
1   10.42"    9/14/1914
 2   10.12"    9/14/1977
 3    8.87"    9/14/1989
 4    8.84"    9/14/2008
 5    8.61"    9/14/1961
 6    6.13"    9/14/1894
 7    6.02"    9/14/1909
 8    5.93"    9/14/1918
 9    5.85"    9/14/1962
10    5.75"    9/14/1889
1    16.17"    9/29/1914
2    11.34"    9/29/1977
3    11.09"    9/29/1961
4    10.79"    9/29/1970
5    10.38"    9/29/1905
6    10.28"    9/29/1973
7     9.87"    9/29/1986
8     9.23"    9/29/1985
9     8.87"    9/29/1989
10    8.84"    9/29/2008

In addition, an abnormally wet month has also added up to an abnormally cool month as well.  In Kansas City, through the 14th of September, the average temperature has been 65.2 degrees or 5.5 degrees below normal!  We have only experienced 2 days with high temperatures above normal, and have also experienced two night time lows temperatures in the 40s!  Through the 14th of the month, this has been the 3rd coldest September in Kansas City history.

 

Lowest Average Temperature degrees F
Days: 9/1 - 9/14
Length of period: 14 days
Years: 1888-2008
 

1    61.2    9/14/1974
2    64.3    9/14/1902
3    65.2    9/14/2008
4    65.6    9/14/1949,  9/14/1989
6    66.2    9/14/1993
7    66.7    9/14/1950
8    67.0    9/14/1890,  9/14/1924
10   67.3    9/14/1891

 

 


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