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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 27, 2021

SPC May 27, 2021 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Thu May 27 2021 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS AND OZARKS... ...SUMMARY... Scattered severe thunderstorms are expected from parts of the southern Plains into the Ozarks and Mid-Mississippi Valley. Significant damaging winds, very large hail, and a few tornadoes are possible. ...DISCUSSION... A few changes have been made to the outlook for this issuance. The first change is to move the slight, marginal and thunder lines further southeast across the Arklatex and lower Mississippi Valley. This will give more room for a linear MCS that is forecast to move southeastward across the region tonight. The second change is to move the marginal and thunder line eastward across southwest Texas to give convection additional room to move eastward this evening. The third change is to remove the slight risk area from parts of north-central Missouri where a morning MCS has stabilized the airmass. A few marginally severe storms with strong wind gusts and hail may still occur late this afternoon and early this evening across northern Missouri. Lastly, the marginal risk has been adjusted a bit eastward across central Kentucky to account for a linear MCS that is moving into the Ohio Valley. ..Broyles.. 05/27/2021 .PREV DISCUSSION... /ISSUED 1110 AM CDT Thu May 27 2021/ ...IL to OK... A complex convective day is expected across the central/southern Plains into the mid MS Valley, with numerous strong to severe thunderstorms over a wide area. Multiple remnant MCV, outflow boundaries, and areas of convection from overnight storms extend from western IL across MO and southern KS into OK and west TX. Morning observed and afternoon forecast soundings show a potent thermodynamic environment to the south of these features, with steep mid-level lapse rates, rich low-level moisture, little capping inversion, and the potential for MLCAPE values of 2500-3500 J/kg. This will likely result in rapid thunderstorm development by mid afternoon near any subtle surface features, with activity sagging southeastward through the evening. Deep-layer shear is sufficient for supercell and bowing structures capable of very large hail and corridors of wind damage. Low-level winds are not particularly strong, so tornado potential will likely be isolated and focus along outflow boundaries, or be associated with QLCS/bowing features this evening. ...West TX... The dryline is expected to focus this afternoon across west TX, with temperatures well into the 90s to the west and dewpoints in the upper 60s to the east. This should be sufficient to eliminate the cap and result in isolated supercell thunderstorms this afternoon and evening. Very large hail and damaging winds will be likely with those storms that form. Read more LIVE: