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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.

Thursday, June 24, 2021

SPC Jun 24, 2021 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0307 PM CDT Thu Jun 24 2021 Valid 242000Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN KS...NORTHERN MO...AND FAR SOUTHEAST NE... ...SUMMARY... A corridor of severe weather (including destructive hail, severe wind and a few tornadoes) is possible late this afternoon into tonight from northern Kansas into northern Missouri and far southeast Nebraska. ...20Z Update... The following changes have been made based on the latest observations and short-term guidance. 1. Removed the Slight Risk across portions of northern IL into southern/central WI, where stabilizing effects of widespread cloudiness and precipitation have reduced the threat to some extent. 2. Expanded the Marginal Risk slightly northward across northern WI, where more substantial heating and destabilization has occurred in advance of a cold front. 3. Trimmed the northern edge of the Enhanced Risk across far southern NE, as it appears the most substantial development later this afternoon/evening will occur to the south and east of the trimmed area. Otherwise, intense thunderstorm development is expected across northern KS into northern MO and far southeast NE late this afternoon and evening. See MCD 1076 and the previous discussion below for more information. ..Dean.. 06/24/2021 .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu Jun 24 2021/ ...Northeast KS into northwest MO... A large MCS is moving slowly eastward this morning across northern MO into central IL. The outflow boundary from this system extends from west-central KS into central MO. Very moist and unstable air is present to the south of the boundary, with dewpoints in the mid 70s and potential MLCAPE values over 4000 J/kg later today. This boundary is expected to lift northward this afternoon to roughly the I-70 corridor of northeast KS (although the ongoing convection over southeast KS lends some uncertainty to afternoon boundary position). Scattered supercell storms are expected to develop in vicinity of the boundary by late afternoon, tracking eastward into northwest MO this evening. Model guidance suggests that the low-level jet will strengthen considerably during the evening, with forecast soundings showing very favorable hodographs for supercells capable of very large hail, damaging winds, and a few tornadoes. Considered adding at 10% tornado threat area, but will defer to 20z update when eventual position of the boundary is better defined. Storms are expected to congeal into a bowing complex through the evening, affecting portions of north-central MO with the threat of rather widespread damaging winds and hail. ...Western and Central KS... A well-defined surface low is forecast to become established over central KS today, with considerable wrap-around low-level moisture in place over much of western and northern KS. This will likely lead to scattered intense thunderstorms later today. Very large hail and damaging wind gusts will be the main threats. Have adjusted the orientation of the SLGT/ENH areas to better reflect the surface low position, and where CAM consensus shows highest confidence in storm coverage. ...Eastern NM/TX Panhandle... A deeply mixed boundary layer will develop this afternoon over much of eastern NM and the TX Panhandle, where scattered high-based thunderstorms are forecast. Locally gusty/damaging wind gusts are possible in the strongest cores. Read more LIVE: