On Saturday April 24, 2010 a powerful storm system spawned severe storms across the entire lower and middle Mississippi River Valley and the Ohio River Valley. By mid afternoon, a line of severe storms developed in western Kentucky and rapidly spread eastward toward central Kentucky. As the line of storms entered Louisville's county warning area, a portion of the line of storms began to surge forward, producing a "bow echo" signature on radar. This signature is a common indicator that severe straight line winds, and brief spin up tornadoes are increasingly likely. This storm signature went on to produce widespread wind damage across portions of central Kentucky and even spawned a brief tornado in northwest Edmonson County. Below you will find a map of the damage path of the tornado, along with radar images, pictures of the damage, and a loop of the "bow echo" evolution.
(Click on the map for a PDF version)
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE LOUISVILLE KY
458 PM EDT SUN APR 25 2010 /358 PM CDT SUN APR 25 2010/
...NATIONAL WEATHER SERVICE CONFIRMS EF-1 TORNADO TOUCHED DOWN IN
NORTHWEST EDMONSON COUNTY...
A STORM DAMAGE SURVEY TEAM CONSISTING OF NWS EMPLOYEES AND EDMONSON
COUNTY EMERGENCY MANAGEMENT CONCLUDED THAT AN EF-1 TORNADO WITH WIND
SPEEDS OF 100 MILES PER HOUR TOUCHED DOWN IN NORTHWEST EDMONSON
COUNTY AT 540 PM CDT SATURDAY APRIL 24 2010. THE TORNADO WAS ON THE
GROUND FOR 2 MINUTES. THE 50 YARD WIDE DAMAGE PATH STARTED NEAR
SUNFISH AND TRAVELED EAST SOUTHEAST FOR 1.1 MILES. ALONG THE PATH...
A WELL BUILT HOME SUFFERED SIGNIFICANT DAMAGE ALONG WITH A SHED THAT
WAS DESTROYED. ALSO...SEVERAL OUTBUILDINGS WERE DAMAGED AND NUMEROUS
HARDWOOD AND SOFTWOOD TREES WERE EITHER UPROOTED OR SNAPPED. TO THE
SOUTH OF THE TORNADO DAMAGE PATH...AN AREA OF STRAIGHT LINE WIND
BEGIN TIME: SATURDAY APRIL 24 2010 - 540 PM CDT
END TIME: SATURDAY APRIL 24 2010 - 542 PM CDT
LOCATION BEGIN: JUST EAST OF SUNFISH IN NORTHWEST EDMONSON COUNTY.
LOCATION END: 1.1 MILES EAST SOUTHEAST OF SUNFISH.
EF-SCALE RATING: EF-1
ESTIMATED WIND SPEEDS: 100 MPH
PATH LENGTH 1.1 MILES
PATH WIDTH: 50 YARDS
The tornado path overlayed on satellite land imagery from Google Earth.
Base reflectivity radar image at the time of the tornado. Notice the notch of lower reflectivity just south of Sunfish. This notch in the reflectivity is due to strong inflow winds into the storm and will coincide with rotational velocity signatures in the image below. Also, note the "bowing" signature from the radar image. This bowing is caused by a strong jet of winds from a general westerly direction that caused the storm to surge forward. If you see the area of dark green intruding on the back edge of the most intense part of the storm, that is the rear inflow jet and the reason the storm "bowed" out.
The corresponding storm relative motion image with the reflectivity signature above. Red indicates motion away from the radar and green indicates motion toward the radar. Notice the counter-clockwise motion directly over Sunfish. This circulation caused the brief spin-up tornado and the resulting damage.
Damage along the tornado path just east of Sunfish in northwestern Edmonson County.
Above is a radar loop of part of the evolution of the "bow echo" that produced widespread damage along its path. Notice how the center of the bow (apex) surges out ahead of the line. The green area punching in behind the apex is indicative of the rear inflow jet and its quick drying of its environment. The rear inflow jet descends and produces strong wind at the surface.