Heavy rain, flash flooding and severe weather threat emerging acrossthe Southern Plains into the Lower Mississippi Valley  throughTuesday & Wednesday.Critical fire danger shifts into Texas Big Bend by Tuesday.Tuesday will fair little better across the Southern Plains as theupper-level low brings cooling aloft and with continued warm, moist airoff the Gulf and dry air from the Mexican Plateau in the low tomid-levels; very unstable weather conditions will exist again across muchof Texas; though the axis of concern will shift ever so southward, fromthe Permian Basin/Edwards Plateau across to the Piney Woods of E Texas andinto Louisiana.  Low level wind profiles become a bit more conducive fortornadoes with similar wind and hail risks.  SPC has an Enhanced Risk (3of 5) across central Texas to west-central Louisiana which also alignswith the hatched area indicating an increased potential for strongtornadoes.  Similarly, with an overlap of additional round and increasedoverall moisture to the area, WPC has a Moderate Risk of ExcessiveRainfall (3 of 4) is up for downstream areas of far E  Texas, northernhalf of Louisiana, southern Arkansas into western Mississippi indicatingbroader areal coverage for potential flash flooding conditions.