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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Wednesday, July 12, 2023

SPC Jul 12, 2023 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Wed Jul 12 2023 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER EASTERN KANSAS AND WESTERN MISSOURI... ...SUMMARY... Severe thunderstorms will be possible across much of Missouri, Illinois, and adjacent portions of the central Plains and Midwest on Wednesday. Damaging winds and large hail should be the main threats, with some potential for significant (75+ mph) severe winds across parts of Missouri, Kansas and vicinity. ...Northern IL/southern WI east to northwest OH/southern lower MI... Current MCS continues a general weakening trend based on IR cloud tops, radar trends and recent reports. Air mass recovery in the wake of the morning convection currently appears plausible, aided by a modestly enhanced low-level jet later this afternoon and evening. Steepening mid-level lapse rates will contribute to moderate/pockets of strong MLCAPE this afternoon, and coupled with 40-50 kts of deep-layer shear would result in a favorable parameter space for supercell development by late afternoon/early evening with all severe hazards possible. Will introduce a small 5 percent tornado probability area across this region, where forecast sounding hodograph structure appears most favorable for low-level rotation/tornado potential east of a weak surface low. ...KS/MO/OK this evening... Redevelopment of severe storms appears probable late this afternoon/early evening in the vicinity of an outflow boundary that continues to slow its southward motion across northern portions of KS/MO. Strong/locally extreme MLCAPE is anticipated near/south of this boundary with substantial shear in the cloud-bearing layer. Storms that develop will likely initially possess supercell characteristics with severe hail (possibly significant) and wind, with eventual upscale growth into one or two MCSs capable of potentially significant severe gusts. The Enhanced Risk area has been reoriented based on expected outflow boundary location later this afternoon and a consensus of 12z CAM guidance/HREF ensemble max probabilities. ...IN/OH into New England... A surface quasistationary front currently extends from northern IN into NY and New England. Substantial heating is underway east of the front, which should allow for destabilization and scattered afternoon thunderstorm development. This area lies along the southern fringe of stronger west/southwesterly flow aloft, with 25-35 knots of deep-layer shear. This may be sufficient for a few strong storms later today capable of gusty/damaging winds. ..Bunting/Weinman.. 07/12/2023 Read more CHECK UPDATE ZOOM GRAPHIC