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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, May 25, 2022

SPC May 25, 2022 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed May 25 2022 Valid 252000Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES AND MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms remain possible from the central Gulf Coast states into parts of the lower/mid Mississippi Valley, Midwest, and Ohio Valley. ...20Z Update... The Slight Risk has generally been trimmed behind a line of thunderstorms ongoing across eastern MS and southeastern LA. Occasional strong to damaging wind gusts should continue to be the main threat with this convection as it spreads into parts of northeastern MS and western AL over the next few hours. See Mesoscale Discussion 915 for more information. Low severe probabilities and a corresponding Marginal Risk have been maintained over much of the lower MS Valley behind the ongoing activity. Most guidance suggests that additional convection will form this evening/tonight along and ahead of a cold front as large-scale ascent associated with an upper low overspreads this region. Low-level shear appears strong enough for a brief tornado or two, and isolated strong to damaging winds may also occur if convection can grow upscale into a line. No changes have been made to the Slight Risk across parts of IL/IN/OH and Lower MI. The environment along/south of a warm front appears conditionally favorable for a mix of multicells and supercells capable of producing both damaging winds and perhaps a few tornadoes. But, it remains unclear whether robust convection will develop across this area through the rest of the afternoon. ..Gleason.. 05/25/2022 .PREV DISCUSSION... /ISSUED 1120 AM CDT Wed May 25 2022/ ...IL/IN/OH... Water vapor imagery shows an upper low over OK, with a negatively-tilted shortwave trough rotating northward across the mid MS Valley. Widespread dewpoints in the 60s to lower 70s are present south of diffuse warm front lifting northward across northern IL/IN, with broken clouds allowing pockets of daytime heating and destabilization. However, mid-level lapse rates are not very steep, limiting afternoon MLCAPE values to generally below 1500 J/kg. The combination of sufficient CAPE and modest large scale support will likely lead to widely scattered thunderstorms by mid/late afternoon. Local VAD profiles and model forecasts show some increase in low and mid level winds through the day, along with sufficient low-level shear for a few rotating storms and bowing structures. While the parameters are subtle, there appears to be some risk of a few tornadoes across this area later today, prompting the addition of a SLGT risk. ...MS/LA/AL... A line of strong/severe storms is tracking eastward across western MS into a moist and unstable air mass. This line may continue to pose a risk of locally damaging wind gusts through the afternoon. Please refer to WW #273 and recent MCD #912 for further details. Read more CHECK UPDATE ZOOM GRAPHIC