TYLER, TX (KTLV) -- A strong cold front will move into East Texas this afternoon and evening bringing with it the possibility of strong to severe thunderstorms. Right now the main threat of severe weather appears to be strong gusty winds and hail up to the size of pennies. This morning, a layer of warm air just above the surface is putting a lid on thunderstorm development until immediately behind the front. This trend will continue until temperatures this afternoon reach the middle to upper 80s across East Texas. Once these temperatures are reached we will see air lifted ahead of the cold front increasing thunderstorm development. Winds throughout the atmosphere ahead of the cold front are out of the southwest limiting the amount of turning of the winds with height, a big factor needed in tornado development. However, with any additional daytime heating this afternoon, enough instability could form to compensate for the lack of vertical wind shear so we can't rule out an isolated tornado, especially over the northeaster parts of East Texas. We could also see some very heavy rain this afternoon as storms continue to develop across the same areas later this afternoon.
In addition to severe weather, parts of East Texas today will come close to having dangerous heat index values. Tremendous amounts of Gulf moisture are in place across East Texas and as temperatures approach 90 degrees, especially across our southwestern counties, heat index values will range between 100 and 105 degrees this afternoon. Across most of East Texas heat index values will reach the middle to upper 90s, something we have not experienced in a while across East Texas. Please use caution later this afternoon with any strenuous outdoor activities.