Link to NWS Louisville Science and Technology Homepage WSR-88D Images of the May 14, 1995 Bow Echo and Tornado Event
Green Line Separater

During the early morning hours of May 14, 1995, a non-severe cluster of convection evolved quite quickly into an intense severe bow echo that raced eastward across north-central Kentucky. The bow cut a swath of major wind damage with widespread straight-line winds over 60 mph with maximum reported gusts around 100 mph. In addition, at least two tornadoes of F1-F2 intensity occurred along the bow as well. The strong straight-line winds downed many trees and power lines, and damaged or destroyed numerous buildings and other structures. Over 10 million dollars of damage was reported in one county alone. A conference paper is available on-line that details the evolution of this storm complex. Below are a series of Doppler radar images from the NWS Louisville WSR-88D showing the evolution of the bow echo.
WSR-88D Image 1: May 14, 1995 Severe Weather Event Base reflectivity image at the lowest radar elevation showed a cluster of non-severe thunderstorms along the Ohio River west of the radar site. Heavy rain and small hail were occurring within the red colors. Note that there was no tight reflectivity gradient along the leading edge of the storms, indicating minimal potential for organized wind damage at this time. However, strong mid-altitude radial convergence (not shown) was occurring aloft in the storms, which can initiate strong downdrafts that subsequently produce significant surface wind damage. Thus, the radar showed a precursor signature that the complex of storms likely would soon intensify.
WSR-88D Image 2: May 14, 1995 Severe Weather Event The intense downdrafts caused a rapid organization and acceleration in the area of thunderstorms, resulting in an arced line of severe storms called a bow echo. Note that an extremely tight reflectivity gradient now existed along the leading edge of the storms. This gradient marked the location of a powerful gust front and very damaging straight-line winds driven by strong dynamics, intense downdrafts, and enhanced rear-to-front flow. A tornado also was occurring at this time near the intersection of the northern end of the bow echo and the east-west zone of thunderstorms in the upper right part of the image.
WSR-88D Image 3: May 14, 1995 Severe Weather Event The bow echo raced eastward across Hardin county in north-central KY producing severe straight-line wind damage. (The radar site at Ft. Knox in far northern Hardin county was within the red colors in the image at left). A tight reflectivity gradient still existed along the leading edge. Damage was most intense along the bow apex where the line was bulged out the greatest. While the first tornado had dissipated by this time, a second tornado was in progress just north of the bow apex along the Hardin-Bullitt county border.
WSR-88D Image 4: May 14, 1995 Severe Weather Event The strongest part of the bow echo moved across Bullitt and into western Nelson county at this time (south of Louisville). Note that a wave structure ("S" shape) existed in the highest reflectivity values (i.e., orange and red colors) over these counties. This wave pattern often is associated with substantial wind damage along the wave crest and possible tornadoes near the inflection point in the wave just north of the crest/bow apex. Indeed, in this case, a tornado that produced F1-F2 damage was in progress over the southern part of Bullitt county. The tornado cut a narrow, but definitive swath of damage, although widespread straight-line wind damage in this case far outshadowed tornado damage.
WSR-88D Image 5: May 14, 1995 Severe Weather Event Corresponding storm-relative velocity (SRM) image over southern Bullitt county. Red (green) colors represent radial winds directed away (toward) the radar located 10-20 miles northwest of the area shown. The small bright green area next to red colors identified the cyclonic circulation producing the tornado at this time. The inbound (green) component of the circulation was resolved by the radar better than the outbound (red) component. Light red colors southwest of the tornado location represented strong rear-to-front flow associated with strong straight-line winds along the bow apex. Light green colors south and east of the tornado represented strong storm-relative flow into the leading convective line.
WSR-88D Image 6: May 14, 1995 Severe Weather Event A time later, the bow echo weakened slightly in intensity as the leading reflectivity gradient began to relax and as the system showed less bowing along its leading edge. Thus, while surface wind damage continued at this time, the degree and extent of damage was less than earlier in the system's evolution. The line of thunderstorms continued to move eastward after this time.

Green Line Separater

Back to WSR-88D Doppler Radar Imagery

   

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.