SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Wed Jul 02 2025 Valid 030100Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MONTANA... ...SUMMARY... Isolated to widely scattered severe thunderstorm gusts remain possible across parts of eastern Oregon into Idaho and Montana this evening. Isolated severe thunderstorms may also occur over portions of the Upper Midwest/Great Lakes. ...Eastern Oregon into the Northern Rockies/High Plains... Convection has developed this afternoon/evening along the western and northern periphery of upper troughing centered over the High Plains. Surface observations and various forecast soundings suggest a very well mixed airmass is present from eastern OR into the northern Rockies/High Plains, with surface temperature/dewpoint spreads of 30-40+ F common. While instability and deep-layer shear are both forecast to remain fairly modest, there may be some loosely organized clusters posing a threat for isolated to scattered severe winds this evening. The greatest concentration of thunderstorms and severe winds may still focus across parts of central/eastern MT over the next several hours, where the Slight Risk has been maintained. See Mesoscale Discussion 1544 for more details on the short-term severe threat across this area. ...Upper Midwest/Great Lakes... Widely scattered thunderstorms should continue across parts the Upper Midwest and Great Lakes this evening, as the glancing influence of upper troughing over Ontario and the northern Great Lakes overspreads this region. Modest low-level flow per area VWPs gradually veers to northwesterly at mid/upper levels, which is supporting around 30-35 kt of deep-layer shear. Occasional thunderstorm organization has been noted with the ongoing activity given a sufficiently unstable airmass, and isolated damaging winds/hail should remain possible for a couple more hours before convection eventually weakens later this evening. ...Great Basin/Southwest... Convection earlier today has largely overturned the airmass across much of NV into western UT. Occasional strong to severe gusts will remain possible with any ongoing/additional convection across the Sierra into the Great Basin and Southwest where low-level lapse rates remain steepened. But, overall severe wind potential is expected to remain rather isolated, with a small Marginal Risk for wind maintained across parts of southern NV and vicinity where low-level lapse rates remain steepened amid 30-40 kt of southerly deep-layer shear. ..Gleason.. 07/03/2025