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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, October 15, 2022

SPC Oct 15, 2022 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1234 AM CDT Sat Oct 15 2022 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHWEST OKLAHOMA TO EASTERN ARKANSAS... ...SUMMARY... Afternoon and evening thunderstorms are expected to evolve from Oklahoma to the Tennessee Valley area. Isolated large hail and strong gusts will accompany these thunderstorms. Additional strong storms may produce sporadic hail and gusty winds across portions of southeast California central and southern Arizona. ...Synopsis... Early-morning surface observations across the southern Plains reveal a cold front beginning to stall across southern KS and northern OK. This boundary will meander southward into central OK/AR through the day and will be the impetus for thunderstorm development later this afternoon and tonight. Across the Southwest, an upper low noted off the coast of southern CA in water-vapor imagery will drift east through the day and support widespread shower and thunderstorm development across southern CA and southern AZ. ...Southern Plains... The stalling cold front across OK/AR is expected to undergo frontolysis through the day amid ample daytime heating across the region. Diurnal boundary-layer mixing coupled with a modest increase in low-level moisture (dewpoints climbing into the 50s and low 60s) should result in 1000-2000 J/kg MLCAPE with minimal inhibition across eastern OK into central AR by late afternoon. Initial thunderstorm development is probable along the I-40 corridor where low-level confluence along the boundary will likely be maximized and inhibition should be weakest. Initially discrete cells will pose a severe hail/wind threat before storm motions along the boundary foster gradual upscale growth and an increasing wind threat into the evening hours for eastern OK/AR. Further west into central/western OK, stronger inhibition should limit convective development until after 00 UTC when lift along the remnant frontal zone increases due to 1) a strengthening low-level nocturnal jet and 2) ascent associated with the approach of an embedded mid-level perturbation (noted in water-vapor imagery over northern MT). Rapid upscale growth is anticipated given mean flow along the boundary, which will predominantly favor a wind threat through the overnight hours, through severe hail is possible with the initial development. ...Southern High Plains... Isolated to scattered convection is expected to move out of Chihuahua, Mexico and into the southern High Plains by the late afternoon/evening hours. This activity will migrate into a deeply-mixed air mass conducive for strong to severe downburst winds. While there is some uncertainty regarding the timing of convection with peak daytime heating/mixing, most guidance suggests a reasonable potential for isolated strong/severe gusts to warrant probabilities. ...Lower Colorado River Valley into southern Arizona... Broad ascent evident in satellite imagery across northern Mexico and southern AZ/NM should remain over the Southwest over the next 24 hours as the upper low drifts to the east. While the 00 UTC TUS sounding sampled very dry boundary-layer conditions, GOES PWAT imagery suggests a reservoir of higher quality low-level moisture is in place through the lower CO river valley and southern AZ where dewpoints are in the 50s. This moisture, coupled with steepening mid-level lapse rates, should support 1000-1500 J/kg MLCAPE by late afternoon. Shower and thunderstorm activity will likely gradually increase through the day in tandem with increasing buoyancy. Strong upper-level flow associated with the wave should support some hodograph elongation and the potential for a few organized cells capable of severe hail/wind. ..Moore/Broyles.. 10/15/2022 Read more CHECK UPDATE ZOOM GRAPHIC
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