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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.

Friday, December 24, 2021

SPC Dec 24, 2021 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CST Fri Dec 24 2021 Valid 271200Z - 011200Z ...DISCUSSION... An upper-level ridge will remain across the southeastern United States for much of the period. Several shortwave troughs will move along the western periphery of this ridge through the period with increasingly rich low-level moisture being pulled northward with each passing wave. By 00Z on D6/Wed, dewpoints are forecast to be 70F or greater across the western 2/3rds of the Gulf of Mexico, which is more reminiscent of late March/early April than December. This will provide a reservoir of ample deep moisture across the Gulf of Mexico which will continue to feed a broad warm sector across the Southeast CONUS. ...D5/Tue - Mid-Mississippi Valley into the Ohio Valley... Medium-range forecast guidance has come into better agreement with a mid-level shortwave trough tracking from the Colorado Rockies to the Upper Midwest during the day on D5/Tuesday. A sub-1000mb lee cyclone is forecast to move eastward through the day and weaken as the mid-level shortwave trough becomes less defined through time. Meanwhile, the low-level jet is forecast to maintain its strength as it shifts east toward the Ohio/Mississippi Valley region. This will help transport low 60s dewpoints into the Ohio Valley with mid 60s dewpoints as far north as western Tennessee. At this time, buoyancy still appears too limited to support a widespread severe weather threat. ...D6/Wed - Portions of the Southeast and the Mid-Mississippi Valley... By Wednesday morning, better instability should be in place across the Southeast. This will likely increase thunderstorm chances along and near a surface front somewhere in the Southeast/Mid-Mississippi Valley. However, by this time the broader pattern appears less favorable with mid-level height rises and only a weak surface reflection (if any) along the front. Beyond D6/Wed, there is considerable uncertainty regarding the upper-level pattern. Rich Gulf of Mexico moisture should remain across the Southeast, which could eventually result in severe weather potential, if the right upper-level system interacts with this broad warm sector. However, there is too much variance at this time to decipher any potential location for severe weather concern. Read more LIVE: