Severe Weather of April 13, 2009

A National Weather Service survey team traveled to Jackson and Lawrence counties and determined that no tornadoes occurred with the severe storms on April 13. The storms did however produce large hail and a funnel cloud. Please read on for more information on these storms. 

Below are some radar images from the storms. Click on any image for a larger version. 

The above pictures show the supercell storm near the time of the first golf ball size hail report received from Medora in Jackson county. You can see the rotation of the storm in the storm relative image on the right (green is wind blowing toward the radar, red is wind blowing away).

These images show the storm about 20 minutes later, about when 1 inch hail was reported near Brownstown in Jackson county. Again, you can see the rotation of the storm in the storm relative image on the right.

The storms developed near a warm front across southern Indiana during the afternoon. Temperatures south of the front were around 70 degrees, which provided instability for the storms. In addition, an area of strong winds high in the atmosphere (jet streak at 300mb) was aiding in providing forcing for the storms.

Above left: Visible satellite image at about 3:00 PM EDT, with surface observations and approximate warm front location. 
Above right: Wind speed (knots) at 300mb. Warmer colors indicate higher speeds.

Below is a list of severe weather reports received so far for Monday's event:

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
827 AM EDT TUE APR 14 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0352 PM     HAIL             MEDORA                  38.82N 86.17W
04/13/2009  E1.75 INCH       JACKSON            IN   LAW ENFORCEMENT

            QUARTER TO GOLF BALL SIZE HAIL

0410 PM     HAIL             BROWNSTOWN              38.88N 86.05W
04/13/2009  E1.00 INCH       JACKSON            IN   POST OFFICE

0415 PM     HAIL             SEYMOUR                 38.96N 85.89W
04/13/2009  E0.88 INCH       JACKSON            IN   AMATEUR RADIO

            REPORTED AT CR 400N AND US50.

0415 PM     HAIL             MEDORA                  38.82N 86.17W
04/13/2009  E1.75 INCH       JACKSON            IN   BROADCAST MEDIA

0422 PM     HAIL             SEYMOUR                 38.96N 85.89W
04/13/2009  E1.00 INCH       JACKSON            IN   LAW ENFORCEMENT

0450 PM     FUNNEL CLOUD     2 N HAYDEN              39.01N 85.74W
04/13/2009                   JENNINGS           IN   AMATEUR RADIO

            REPORTED AT APPROX 5 MIN AGO BY LOCAL SPOTTER.

0513 PM     HAIL             FRANKLIN                39.49N 86.06W
04/13/2009  E0.88 INCH       JOHNSON            IN   AMATEUR RADIO

            PEA TO MARBLE SIZE HAIL ALSO REPORTED.