SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1133 PM CDT Tue Sep 30 2025 Valid 021200Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. Thursday through Thursday night. ...Discussion... It appears that stronger, more zonal and progressive mid/upper flow will become increasingly confined to the higher latitudes during this period, while a branch of westerlies across the mid-latitude Pacific into the western U.S. trends more amplified. Near the leading edge of the lower latitude regime, this is forecast to include a notable short wave trough digging inland across the northern/central California coast vicinity late Thursday through Thursday night. In advance of this perturbation, models indicate that mid-level ridging will build north-northeast of a subtropical high centered over the Mexican Plateau, and within the mid-latitude westerlies across the Great Plains. Downstream, it appears that ridging in the mid-latitude westerlies will broaden eastward offshore of the northern and middle Atlantic coast, while broad, weak troughing in the subtropical latitudes digs a bit further, south-southwestward through the Gulf Basin. Beneath this regime, though slowly weakening while becoming centered near or just offshore of the northern Mid Atlantic coast, a surface ridge may continue to encompass an expansive area from the Gulf coast and southern Great Plains through the northwestern Atlantic. ...Great Basin into northern Rockies... A corridor of scattered thunderstorm development still appears possible, mostly near a frontal zone across parts of southwestern Montana through north central Nevada, after 03/00Z Thursday evening into Thursday night. This is expected to be aided by forcing for ascent downstream of the inland digging short wave trough, in the presence of strengthening deep layer shear becoming conditionally supportive of organized convective development. However, due to thermodynamic profiles supportive of only rather weak CAPE, and characterized by a stabilizing boundary due to the onset of diurnal cooling, the risk for severe weather still appears negligible. ...Southern Florida Peninsula... Scattered thunderstorm development appears likely within moist east-northeasterly post-frontal low-level flow, with thunderstorm probabilities perhaps highest where low-level convergence becomes focused across southeast coastal areas, in the presence of weak to moderate CAPE. An isolated strong wind gust may not be entirely out of the question, aided by heavy precipitation loading, but generally weak low/mid-level flow and shear still seem likely to minimize the risk for severe weather through this period. ..Kerr.. 10/01/2025
