A supercell is sitting just southwest of Junction or just northwest of Telegraph. This storm is slowly moving southeast and may contain hail up to the size of tennis-balls and damaging wind gusts over 70 MPH. The slow movement of this storm and very heavy rain associated with it does make me worried about potential flash flooding in the Junction and Telegraph areas. I wouldn’t be surprised to see a quick 3 to 5 inches of rain over the next hour which would undoubtedly result in rapid flash flooding. Additional storms extend west in a broken line from Juno to Pumpville. These storms are also capable fo producing large hail and are moving southeast slowly. Additional storms are developing from near Kerrville to near Harper – just southeast of the big supercell near Junction. Its unclear if this is a sign that we may have more storms forming on an outflow boundary in that area but its possible over the next hour. Assuming the cell near Junction organizes into a damaging wind producer it may start to move southeast more quickly towards Kerrville. We’ll have to watch for that possibility. High-resolution models are indicating that a line of storms may form in that area – kind of like what is going on now. Should that occur the threat for more widespread damaging wind gusts could increase as a squall line moves southeast towards Kerrville-Uvalde area. I don’t know if this line will directly impact San Antonio tonight but if it does that threat is still several hours away.
Multiple severe thunderstorms have broken out in Deep South Texas with temperatures soaring into the 90s this afternoon. Most storms are moving to the east or southeast at a snails pace. The most intense storm at the time of this writing is 30 miles east/southeast of Laredo. That storm has a history of producing baseball to softball size hail in Ranchitos Las Lomas – about 15 miles northeast of Laredo on Highway 59 just after 7 PM. Unlike the storms further north these are being driven more thermodynamically and thus should start to weaken in the 9 PM to 11 PM timeframe. Until then the threat for significant hail up to the size of baseballs will remain possible with the strongest storms. A tornado is not out of the question as low-level shear increases after sunset.