...Bow Echo Affects East Central Kansas through Central Missouri...
A complex of thunderstorms developed Friday evening along the intersection of an outflow boundary and warm front across central and eastern Kansas. This complex grew into an organized bow echo, which rapidly moved from east central Kansas through central Missouri. By the time the thunderstorms reached near the southern portions of the Kansas City metropolitan area, most of the hail was very small, however this bow echo generated very strong wind gusts between 60 and 80 mph. This lead to widespread tree damage and numerous power outages in a swath from Miami and Johnson counties in Kansas, through parts of Jackson, Cass, and Johnson counties in Missouri. Below are radar reflectivity and velocity loops depicting the evolution of this bow echo, with a few tree damage photos.
KEAX Radar Reflectivity KEAX Radar Velocity

Storm Reports from the evening/overnight June 17-18, 2011:

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
935 AM CDT SAT JUN 18 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0100 AM TSTM WND GST 8 WNW HILLSDALE 38.71N 94.99W
06/18/2011 E80.00 MPH MIAMI KS LAW ENFORCEMENT
WINDS OF 60 TO 80 MPH REPORTED JUST EAST OF WELLSVILLE KS
0108 AM TSTM WND GST HILLSDALE 38.67N 94.85W
06/18/2011 E80.00 MPH MIAMI KS LAW ENFORCEMENT
0113 AM TSTM WND GST 2 NE GARDNER 38.83N 94.90W
06/18/2011 M67.00 MPH JOHNSON KS ASOS
MEASURED AT OLATHE NEW CENTRURY AIRPORT IXD
0118 AM TSTM WND GST OLATHE 38.89N 94.81W
06/18/2011 E60.00 MPH JOHNSON KS PUBLIC
VIA TWITTER
0119 AM TSTM WND GST 5 SE OLATHE 38.84N 94.75W
06/18/2011 M52.00 MPH JOHNSON KS ASOS
MEASURED AT OLATHE JOHNSON COUNTY EXECUTIVE AIRPORT OJC
0120 AM TSTM WND GST LOUISBURG 38.62N 94.68W
06/18/2011 E70.00 MPH MIAMI KS LAW ENFORCEMENT
ALSO TREE DAMAGE REPORTED
0135 AM TSTM WND DMG 3 E LEES SUMMIT 38.92N 94.33W
06/18/2011 JACKSON MO NWS EMPLOYEE
60 MPH WINDS AND TREE BLOWN DOWN
0139 AM TSTM WND DMG SHAWNEE 39.02N 94.80W
06/18/2011 JOHNSON KS PUBLIC
6 INCH DIAMETER TREE LIMB BROKEN FROM TREE...VIA TWITTER
0140 AM TSTM WND GST BELTON 38.81N 94.53W
06/18/2011 E65.00 MPH CASS MO FIRE DEPT/RESCUE
13 INCH TREE LIMBS BLOWN DOWN
0141 AM TSTM WND DMG 1 WSW BELTON 38.81N 94.55W
06/18/2011 CASS MO NWS EMPLOYEE
HALF OF LARGE TREE BLOWN DOWN
0142 AM TSTM WND GST GRANDVIEW 38.88N 94.52W
06/18/2011 E75.00 MPH JACKSON MO LAW ENFORCEMENT
0144 AM TSTM WND GST 8 W HARRISONVILLE 38.66N 94.50W
06/18/2011 E65.00 MPH CASS MO LAW ENFORCEMENT
0148 AM TSTM WND GST 4 N LEE`S SUMMIT 38.97N 94.38W
06/18/2011 M50.00 MPH JACKSON MO ASOS
MEASURED AT THE LEES SUMMIT AIRPORT LXT
0152 AM TSTM WND DMG BLUE SPRINGS 39.02N 94.28W
06/18/2011 JACKSON MO TRAINED SPOTTER
WIDE SPREAD TREE DAMAGE
0156 AM TSTM WND GST 1 N PLEASANT HILL 38.81N 94.27W
06/18/2011 E60.00 MPH CASS MO NWS EMPLOYEE
AT LEAST 60 MPH WINDS AT NWS PLEASANT HILL
0158 AM TSTM WND GST 2 SW BLUE SPRINGS 39.00N 94.31W
06/18/2011 E70.00 MPH JACKSON MO NWS EMPLOYEE
0159 AM TSTM WND DMG 8 SW HOLDEN 38.63N 94.09W
06/18/2011 JOHNSON MO AMATEUR RADIO
TREE BRANCH FELL ON POWERLINE...KNOCKING THE LINE DOWN
0204 AM TSTM WND GST 2 WNW HARRISONVILLE 38.67N 94.38W
06/18/2011 E70.00 MPH CASS MO PUBLIC
ALSO 24 FOOT FLAG POLE BLOWN OVER
0204 AM TSTM WND GST HARRISONVILLE 38.66N 94.35W
06/18/2011 E65.00 MPH CASS MO AMATEUR RADIO
0232 AM TSTM WND GST WHITEMAN AFB 38.73N 93.55W
06/18/2011 M62.00 MPH JOHNSON MO ASOS
0242 AM TSTM WND GST WHITEMAN AIR FORCE BASE 38.73N 93.55W
06/18/2011 M62.00 MPH JOHNSON MO ASOS
MEASURED AT WHITEMAN AIR FORCE BASE ASOS SZL
0250 AM TSTM WND GST CLINTON 38.37N 93.77W
06/18/2011 M56.00 MPH HENRY MO AWOS
0312 AM TSTM WND DMG LEETON 38.58N 93.70W
06/18/2011 JOHNSON MO LAW ENFORCEMENT
1.5 FOOT DIAMETER TREE BLOCKING 2 HWY AND EE HWY
0321 AM TSTM WND DMG FREEMAN 38.62N 94.51W
06/18/2011 CASS MO LAW ENFORCEMENT
TREE AND HOUSE DAMAGE. DAMAGE TO A GAS STATION AT C HWY
AND 2 HWY
0324 AM TSTM WND DMG SEDALIA 38.70N 93.23W
06/18/2011 PETTIS MO AIRPLANE PILOT
ROOF CAME OFF OF ONE HOUSE AND LANDED ON ANOTHER