SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1102 AM CST Wed Jan 21 2026 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Aside from the risk for a few weak thunderstorms near southeastern Florida coastal areas, potential for thunderstorm development appears low across the U.S. Thursday through Thursday night. ...Discussion... A vigorous short wave trough emanating from the Canadian Arctic latitudes is forecast to dig southeast of the international border, across parts of the Upper Midwest and Great Lakes region, and contribute to the maintenance of larger-scale mid-level troughing across the northern U.S. Great Plains through northern and middle Atlantic Seaboard. Beneath an increasingly confluent regime in its wake, models continue to indicate that a rather prominent, cold surface ridge will build southeastward along an axis across the middle/lower Missouri Valley into lower Ohio Valley by late Thursday night. It appears that a preceding surface frontal zone will stall and perhaps strengthen across the Carolinas through northern portions of the Gulf Coast states into southern Great Plains. Another is expected to slowly weaken across the Florida Peninsula and northern Gulf Basin, as much of the southern tier of the U.S. continues to come under the increasing influence of westerlies emanating from the mid- to subtropical eastern Pacific. Downstream of fairly sharp building mid-level ridging across the eastern mid-latitude Pacific, models have come in better agreement concerning a digging mid-level trough and embedded low offshore of the southern California/northern Baja Pacific coast. It is becoming more certain that the cyclonic circulation and colder temperatures associated with an elongating mid-level cold core will generally remain offshore of the southern California, before turning inland across northern Baja after 12Z Friday. ...Southern California... Models continue to indicate coldest offshore mid-level temperatures at a somewhat modest -22 to -24C around 500 mb. However, based on the latest Rapid Refresh and NAM forecast soundings, weak destabilization supportive of short-lived weak thunderstorm development may not be entirely out of the question near coastal areas, particularly where forcing for ascent is aided by orography near the Transverse and perhaps Peninsular Ranges. Certainty does not yet appear high enough for the minimum 10 percent threshold, but this will continue to be monitored. ...Gulf Coast States... Given the general tendency for warming mid-levels, and the lack of both more substantive further low-level moistening off a slowly modifying Gulf boundary layer and mid/upper support for ascent, the risk for thunderstorm activity still appears minimal Thursday through Thursday night. The primary exception still appears near southeastern Florida coastal areas, in response to increasing boundary-layer destabilization and convergence, near developing surface troughing and the remnant surface front, perhaps aided by forcing associated with weak perturbations within the subtropical westerlies. ..Kerr.. 01/21/2026
