SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 AM CDT Thu Jun 12 2025 Valid 121300Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FOR PARTS OF NEBRASKA AND SOUTH DAKOTA... ...SUMMARY... Scattered areas of strong thunderstorm development are possible today into tonight, accompanied by potential for severe hail and wind across parts of the Great Plains, the Upper Midwest, the Texas coastal plains into lower Mississippi Valley and a small portion of the northern Mid Atlantic. ...NE/SD... Morning water vapor imagery shows a shortwave trough over eastern MT, with a mid-level speed max tracking across WY. Large-scale lift associated with the jet max will overspread parts of NE/SD by late afternoon along a stalled surface boundary. At least widely scattered thunderstorm activity is expected for a few hours (mainly 21-03z), with forecast soundings suggesting sufficient deep-layer shear for a few organized/rotating cells. Locally damaging winds and hail are possible. Overnight CAM guidance has shown consistency on the corridor most likely to see storms, so have added a narrow SLGT to cover this threat. ...East TX/LA/AR... An upper trough is located over central TX, where widespread thunderstorms are ongoing this morning. A few of these storms have shown supercell tendencies overnight. Model guidance and local VAD data suggest a region of enhanced low/mid level flow to the east of the upper trough, extending from central into northeast TX. As the trough moves northeastward today, the combination of a very moist and modestly unstable air mass, sufficient low/deep layer shear, and considerable coverage of thunderstorms, will contribute to a risk of a few locally damaging wind gusts and/or tornadoes. Will maintain MRGL risk for today due to widespread clouds and limited opportunity for heating. ...GA/SC/NC... Strong heating is expected today across parts of GA/SC/NC, where temperatures in the upper 80s and dewpoints near 70F are forecast. This will lead to widespread moderate CAPE values and the development scattered afternoon thunderstorms. Vertical shear is weak, but a few weakly organized thunderstorm clusters may reach severe intensity with gusty/damaging winds. ..Hart/Bentley.. 06/12/2025