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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.


Saturday, January 1, 2022

SPC Jan 1, 2022 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0158 PM CST Sat Jan 01 2022 Valid 012000Z - 021200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF NORTHERN MS/AL...MIDDLE/EASTERN TN...FAR NORTHWEST GA...EXTREME SOUTHEAST KY... ...SUMMARY... Tornadoes, a couple of which could be strong, and damaging winds will be possible through tonight, especially across the Tennessee Valley. ...20Z Update... The primary change to the outlook is to clear severe-hazard and thunder probabilities in the wake of ongoing storms along the convectively reinforced surface boundary. Otherwise, potential remains for discrete supercell development within the warm sector, especially across northern MS/AL into middle TN, though coverage of any such activity remains uncertain. Any mature supercells ahead of the surface boundary would pose a conditional threat for tornadoes, including the potential for a strong tornado or two. Otherwise, widespread convection along the primary surface boundary will pose a threat for scattered damaging wind gusts and a couple of tornadoes as it moves eastward into this evening. See the previous discussion below for more information. ..Dean.. 01/01/2022 .PREV DISCUSSION... /ISSUED 1023 AM CST Sat Jan 01 2022/ ...Ark-La-Tex to the TN Valley... Convection has persisted along a baroclinic zone demarcating the northwest edge of the richer low-level moisture from the Ark-La-Tex into western TN/KY. The convection has reinforced this boundary with modest pressure rises behind it, resulting in it receding southeast in the Mid-South. It is very unlikely to return north, given the lack of appreciable cyclogenesis as a result of an expansive cold air mass across the central U.S. that will undercut the stronger forcing for ascent in advance of the primary shortwave trough over the Four Corners. Even though the main surface cyclone will not be intense and will develop farther away from the warm sector (in tandem with an ejecting shortwave trough over KS/OK), strong deep-layer wind fields and vertical shear will persist through the day and into tonight in the warm sector across the TN Valley. Given the persistence of the subtropical ridge over FL and only glancing/small height falls through the day, much of the convection may remain confined to the convection-reinforced frontal zone. Still, there will be the potential for embedded supercells within a broken band of storms along the front, and a lower chance for a few supercells in the open warm sector along diffuse confluence zones a little south of the front later this afternoon/evening. Effective bulk shear of 60-70 kt and MLCAPE of 500-1500 J/kg will conditionally support supercells capable of producing tornadoes, damaging winds, and marginally severe hail. The prospects for a couple strong tornadoes will likely hinge on pre-frontal supercell development that is not entirely undercut by the surface front. This is most likely from northern portions of MS/AL into middle TN where effective SRH in excess of 300 m2/s2 should be common late this afternoon/evening. The frontal convection will spread southeast through the overnight hours, with a gradually lessening severe threat and shrinking warm sector centered on AL toward the end of the period. Read more LIVE:
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