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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, October 13, 2021

SPC Oct 13, 2021 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Wed Oct 13 2021 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS...MID/UPPER MISSISSIPPI VALLEY...AND OVER PARTS OF TEXAS... ...SUMMARY... A few strong storms may develop later today across portions of the northern Plains, middle/upper Mississippi Valley, and across parts of Texas. Gusty winds are the primary threat, although a brief tornado can not be ruled out. ...Northern Plains to Mid Mississippi Valley... Intense 12hr mid-level height falls (210m) will spread across the northern Plains into the upper MS Valley during the day ahead of a negative-tilt ejecting short-wave trough. Latest NAM guidance suggests the exit region of a strong 500mb jet will translate across eastern SD by mid day before shifting into northern MN by late afternoon. Surface low is expected to deepen through 18z before it occludes over the Dakotas. As a result, a narrow corridor of surface heating is expected across eastern SD into western IA. Steepening low-level lapse rates will contribute to weak buoyancy across this region, likely sufficient for a few robust updrafts within a strongly sheared environment. Greatest risk is for locally damaging winds; however, a brief tornado can not be ruled out given the dynamic system. Across the mid/upper MS Valley, strong LLJ will be focused across eastern KS into southwest IA early in the period. This feature will shift northeast and weaken slightly as it responds to the ejecting short wave over the northern Plains. Early-day buoyancy will not be particularly noteworthy across this region with poor lapse rates limiting instability. Even so, strong shear will contribute to the potential for at least gusty winds with a few storms. ...Texas... Surface front will arc across the MS Valley-southeast OK-south-central TX at 18z today. This feature will move little during the period and serve as the focus for potentially strong, but extensive convection through the period. Tropical Storm Pamela is currently noted just southeast of the Baja Peninsula near 22N/108W. This TC is forecast to track northeast across Mexico toward southwest TX by sunrise Thursday. High-PW air mass will extend along this boundary with strong deep-layer flow, but poor lapse rates. Given the high moisture content, there is some concern for gusty winds and perhaps even a brief tornado as convection that develops along this zone will be amply sheared for storm organization. ..Darrow/Moore.. 10/13/2021 Read more LIVE: