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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, March 22, 2023

SPC Mar 22, 2023 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Wed Mar 22 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF NORTHEASTERN KANSAS EASTWARD TO NORTHERN INDIANA... ...SUMMARY... Isolated/elevated strong to severe thunderstorms -- capable of large hail -- are possible from far northeast Kansas eastward to northern Indiana late tonight. ...Synopsis... An upper trough across the western U.S. will move gradually eastward with time, with the broader cyclonic flow field to encompass roughly the western half of the country through the period. As this trough advances, downstream ridging centered over the Gulf of Mexico will amplify a bit, with a trend toward a bit of anticyclonic curvature within the westerlies across the central and eastern U.S. with time. At the surface, a low initially over the northern Minnesota vicinity is forecast to shift quickly northeastward into -- and then across -- Ontario through the period. Meanwhile, the trailing cold front will become an increasingly west-to-east quasi-stationary front from the central Plains into the Midwest. This boundary -- or more specifically, a zone of warm advection focused to the cool side of the front -- will focus a zone of elevated convection through the period. ...Northeastern Kansas to northern Indiana... Elevated showers and isolated/embedded thunderstorms are forecast to be ongoing at the start of the forecast period across the northern Missouri vicinity -- i.e. portions of the MRGL risk area. This convection is forecast to shift eastward across the Midwest region through the day. Meanwhile, as a southwesterly low-level jet redevelops later this evening, a gradual increase in new, elevated convection is expected, in tandem with the increase in low-level warm advection atop a surface-based stable layer. With continued low-level theta-e advection within the 900 to 700 mb layer, and some steepening of lapse rates aloft, the elevated destabilization will likely be sufficient to support locally strong/vigorous updrafts. This, combined with favorably strong speed shear through the cloud-bearing layer, will likely support locally severe storms, capable of producing large hail. With time, an expanding convective cluster is forecast to spread eastward, crossing central Illinois and eventually northern Indiana through the end of the period. ..Goss/Lyons.. 03/22/2023 Read more CHECK UPDATE ZOOM GRAPHIC