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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, May 13, 2021

SPC May 13, 2021 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Thu May 13 2021 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...

SUMMARY... Isolated severe thunderstorms may develop Saturday across portions of the southern/central Plains. ...

Southern/Central Plains... A closed upper low should move slowly southward across CA on Saturday, with downstream shortwave ridging persisting over the southern/central Rockies and High Plains. Low-level moisture is expected to gradually increase across the southern/central Plains through the period, but it should still be fairly limited for this time of year. At the surface, a weak low may deepen slightly through the day across part of the southern/central High Plains, with a dryline/lee trough extending southward from this low over the southern High Plains. A warm front should be located across parts of KS by Saturday evening. Mid-level flow is forecast to remain rather weak across much of the warm sector, with marginally stronger winds aloft in a narrow corridor from eastern CO into KS and vicinity. Modest effective bulk shear may temper the overall severe threat to some degree. But, there will likely be steep mid-level lapse rates emanating from an EML across the southern/central High Plains. These lapse rates coupled with diurnal heating of the gradually moistening low-level airmass should support the development of moderate to potentially strong instability along/east of the surface low and dryline. 

Another source of uncertainty is the lack of obvious large-scale ascent to foster convective initiation, as weak upper ridging should be located over the warm sector. Still, storms forming over the higher terrain of the southern/central Rockies will probably spread eastward through the day, and should eventually encounter a more unstable airmass. Weak low-level upslope flow in central/eastern CO may also serve as a forcing mechanism for convective initiation. Other storms may form along the dryline/lee trough. Although low/mid-level winds should remain generally weak through the day, increasing high-level flow may support some venting at anvil level, and semi-organized clusters capable of producing both isolated large hail and damaging winds appear possible as they move generally eastward through the early evening. A southerly low-level jet is forecast to strengthen Saturday evening across southern KS into northern OK, and this feature may support a continued isolated severe threat with any storms that can form/persist in the warm advection regime. ..Gleason.. 05/13/2021 Read more LIVE:

NWS SPC Convective Outlook provided by

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