Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CST Tue Feb 17 2026 Valid 201200Z - 251200Z ...DISCUSSION... In general, the latest medium-range guidance indicates that an initially notable surface cyclone over the upper Great Lakes region at the outset of the period will undergo substantive weakening, as a supporting short wave impulse becomes sheared and weakens to the south of a blocking mid-level ridge centered over southern Hudson Bay. It appears that secondary cyclogenesis across and offshore of the Mid Atlantic coast Friday through Friday night will be subdued, with a trailing cold front stalling across the southern Atlantic through Gulf coast vicinity into Saturday, near the southern periphery of the seasonably strong westerlies. Forcing for ascent associated with trailing short wave perturbations, emerging from larger-scale mid-level troughing progressing out of the West, may remain largely to the cool side of the surface frontal zone. However, further moistening along it could support sufficient destabilization for vigorous, perhaps upscale growing and training, thunderstorm development, which could pose at least some risk for producing severe hail and wind. While severe thunderstorm probabilities are being maintained at less than 15 percent in this outlook, it is still possible that this could change in later outlook updates for the Friday/Saturday time period. Thereafter, amplifying mid/upper flow across the eastern mid-latitude Pacific into North America through early next week appears likely to include building large-scale ridging inland of the Pacific coast through the Mississippi Valley. Beneath the confluent regime in the wake of digging downstream troughing, cold surface ridging is forecast to build southward to the lee of the Rockies, through much of the Gulf Basin. Associated low-level drying and stabilization probably will tend to limit convective potential through the remainder of the period.Read more
