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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, August 18, 2021

SPC Aug 18, 2021 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0106 AM CDT Wed Aug 18 2021 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL HIGH PLAINS VICINITY... ...SUMMARY... A few strong/severe storms may occur from the central and northern High Plains region into the Dakotas Thursday afternoon and evening. ...Synopsis... While weak short-wave troughing moves across the Northeast Thursday, a much stronger upper system -- opening into a progressive trough with time -- will shift across the Intermountain West. At the surface, the main feature will be a slow-moving cold front that will cross the northern Plains/central High Plains region through the period. ...Central High Plains northeastward into North Dakota... As an upper low gradually shifts eastward, and smaller-scale disturbances rotate northeastward through south-southwesterly flow aloft ahead of the low, large-scale ascent will focus along the north-northeast to south-southwest surface front. Ascent will also focus at low levels within post-frontal upslope flow regime over parts of eastern Wyoming and northeast Colorado. While stronger flow aloft will remain to the cool side of the front, 30 to 40 kt southwesterly flow will contribute to ample shear -- accentuated by an increasing southerly low-level jet through the evening hours. As afternoon heating results in sufficient destabilization near and ahead of the front to support scattered storm development, convective intensity will locally be aided by the aforementioned/sufficiently sheared environment. Along with potential for hail -- especially during the initial, afternoon stages of the event -- damaging winds will also be possible locally. With some potential that storms grow upscale into northeastward-moving bands, damaging-wind potential could maximize during the evening hours. Storms will likely continue through the overnight period owing to the strong low-level warm advection, but severe risk should gradually wane as the boundary layer stabilizes. ..Goss.. 08/18/2021 Read more LIVE: