SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0250 PM CDT Sun Oct 10 2021 Valid 102000Z - 111200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING ACROSS PARTS OF OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING OVER NORTHEAST MINNESOTA... ...SUMMARY... Tornadoes, widespread damaging wind gusts, and very large hail are forecast this afternoon and evening for portions of Oklahoma and north Texas. ...MN... Only minor changes have been made to the Slight risk area across northern MN with the 20z update. Slight risk probabilities have been nudged southward a small amount based on ongoing convection this afternoon. Hail and a couple of tornadoes will be possible through early evening with WW 516 in effect until 02z. ...Southern Plains... The previous outlook remains on track and no changes have been made with the 20z update. Initial supercells are expected to initiate over southwest OK near the surface low by around 22z and track east/northeast toward central OK (including the OKC metro area) by 00z. Very large hail, damaging gusts and potentially significant (EF2+) tornadoes will be possible. As the surface cold front starts to surge south/southeast this evening, upward development into a fast-moving QLCS capable of widespread damaging wind gusts, tornadoes and hail will sweep across central/eastern OK (including the Tulsa metro area by around 02-03z). For more details on the short term severe risk reference MCD 1820. Scattered storms will also develop southward along the surface dryline/cold front across northern/central TX by 23-00z (and the Dallas-Fort Worth metroplex by around 01-02z). Initial supercells may evolve into a broken line with eastward extent through the evening, but large hail, damaging gusts and a few tornadoes all will be possible with this activity. ..Leitman.. 10/10/2021 .PREV DISCUSSION... /ISSUED 1116 AM CDT Sun Oct 10 2021/ ...OK... An intense and fast-moving shortwave trough over western NM will pivot into the southern Plains this afternoon. Ahead of this trough, a surface low is forecast to rapidly deepen over western North TX and track northeastward into central OK this evening. Strong and strengthening low-level wind fields in the warm sector of the low will transport Gulf moisture northward, with dewpoints in the mid-upper 60s expected across the region. A combination of ample sunshine and slowing cooling mid-level temperatures will yield MLCAPE values around 2000 J/kg by peak heating, with a slowly weakening cap. Current indications are that storms will begin to rapidly intensify after 21z near the surface low in southwest OK. Some of this activity will be north of the associated cold front, with a primary risk of large hail. However, morning CAM solutions continue to suggest that discrete supercell development is possible near the low and along the trailing dryline. These storms will be in an environment of rapidly strengthening low/mid level wind fields and vertical shear, steep lapse rates, and intense large-scale forcing. Forecast soundings/hodographs in the warm sector would favor the potential for strong tornadoes, very large hail, and significant damaging winds as storms track across central OK - mainly after dark. Storms will become more numerous as they race northeastward into eastern OK during the evening. A few discrete supercells may persist, along with an increasing threat of QLCS-associated wind damage and tornadoes. It appears likely the storms will begin to weaken as they move into parts of western MO/AR around midnight. ...TX... Farther south, model consensus shows scattered thunderstorms developing this evening along the dryline across northern and central TX - especially as the cold front overtakes the dryline. Strong forcing aloft and strengthening wind fields will pose a risk of a scattered supercells along this corridor, capable of a few tornadoes, large hail, and damaging winds. ...MN... An upper low over MN will move slowly eastward today, helping to initiate scattered afternoon thunderstorms over the Arrowhead region. Extensive low clouds in this area will limit daytime heating and destabilization. However, a few of the low-topped storms may be capable of hail or brief tornadoes for a few hours this afternoon. Storms should track northward and into Canada around dusk, ending the threat. Read more LIVE: spc.noaa.gov
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