Link to NWS Louisville Science and Technology Homepage WSR-88D Images of the May 28, 1996 Supercell and Tornado Event
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On May 28, 1996, a severe thunderstorm developed over south-central Indiana, then "split" into two separate severe storms. The northern storm headed northeast as a "left-moving" storm and produced some wind damage and hail before weakening. The southern storm turned east-southeast and evolved into a classic "right-moving" supercell that produced wind damage, large hail, and at least 4 tornadoes along its path through north-central and east-central Kentucky. The strongest tornado was estimated on the ground for about 30 miles and was categorized as an F3 with isolated F4 damage over parts of northeast Bullitt and Spencer counties in north-central Kentucky (just south and southeast of Louisville). This tornado produced severe structural damage to many homes in the area; some homes were destroyed. The following series of Doppler radar images from the NWS Louisville (KLVX) WSR-88D show the overall evolution of this storm.
WSR-88D Image 1: May 28, 1996 Severe Weather Event Base reflectivity data (lowest radar elevation) showing a severe storm in progress across southern Dubois county in south-central Indiana (northwest of Louisville). The storm was moving east-northeast producing strong winds and hail. The heaviest rain and hail were located in the western quadrant of the storm (red colors) with lighter rain to the east.
WSR-88D Image 2: May 28, 1996 Severe Weather Event Ten to twenty minutes later, the storm was undergoing a split with two distinct cells apparent. Note that the tightest reflectivity gradient was on the south side of the southern storm and the north side of the northern storm. This is typical in "mirror-image" splitting storms and represents the most likely location within these type of storms for severe weather phenomena.
WSR-88D Image 3: May 28, 1996 Severe Weather Event About 10 minutes later, the splitting process continued. Note that the red colored areas were now completely separate with lighter reflectivity returns between the 2 storms. This likely was a downdraft area that was promoting the split. The southern storm started to take on some curvature on its southern flank indicating an increase in severe weather activity.
WSR-88D Image 4: May 28, 1996 Severe Weather Event The split was complete 10 to 20 minutes later with an almost mirror effect to the 2 storms, albeit a stronger southern storm. The "left mover" (northern storm) had a tight reflectivity gradient on its northern side where strong winds and hail occurred. This storm then weakened after this time. The southern "right moving" storm was evolving into a classic supercell with a hook echo on its southwest flank and a "V notch" (note the red colors), i.e, blocking flow pattern aloft, just downwind in reflectivity data. The first tornado (F2) touched down around this time with the southern cell.
WSR-88D Image 5: May 28, 1996 Severe Weather Event The mature right-moving supercell continued to move east-southeast. While the first tornado dissipated, golfball size hail fell in southwest Jefferson county, KY (near Louisville). At left, the storm is shown over northeast Bullitt, southeast Jefferson, and Spencer counties in north-central KY. A definitive hook echo is present over Bullitt county indicative of a strong, cyclonically-rotating updraft, i.e., mesocyclone wrapping precipitation around the circulation. A second strong tornado (maximum strength F3-F4) developed and was on the ground within the hook area. Just north of the tornado, large hail and very heavy rain were occurring (dark red and pink colors). Downwind, moderate and heavy rain fanned out in a "V notch" signature.
 WSR-88D Image 6: May 28, 1996 Severe Weather Event This is a low-level storm-relative velocity (SRM) image at the same time as shown in the reflectivity image above. Green colors are storm-relative radial winds directed toward the radar (located to the west of the image); red is flow away from the radar. A tight tornado vortex signature (TVS) is evident near the town of Mt. Washington in northeast Bullitt county (20-25 miles east of the radar), which was coincident with the hook echo in the corresponding reflectivity image above. The TVS was associated with a strong tornado on the ground. Just northeast of the TVS, light green colors denoted strong storm-relative flow into the parent mesocyclone of the supercell.
 WSR-88D Image 7: May 28, 1996 Severe Weather Event The storm continued east into Spencer county, KY where a mature hook echo still was evident on the supercell's southwest quadrant. The tornado was still on the ground at this time producing structural damage to homes and uprooting and debarking numerous trees. Heavy rain and hail continued just north and east of the hook.
 WSR-88D Image 8: May 28, 1996 Severe Weather Event Corresponding storm-relative velocity (SRM) data for the reflectivity image shown above. The radar is located to the west (left) of the image. A tight circulation again is evident over west-central Spencer county, coincident with the hook in the reflectivity image above. The associated tornado eventually weakened and lifted over eastern Spencer county, although 2 additional, but weaker (F0-F2) tornadoes occurred along the storm's path over east-central KY. The storm then gradually weakened and was overtaken by an approaching squall line (not shown).

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