SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0148 PM CST Tue Nov 10 2020 Valid 102000Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MS VALLEY/UPPER MIDWEST... ...SUMMARY... Thunderstorms capable of producing damaging to severe winds and a few tornadoes will remain possible this afternoon and evening from parts of Missouri northeastward into portions of far eastern Iowa, Illinois, and Wisconsin. ...20Z Update... A QLCS will continue moving northeastward across IL and into southern WI this afternoon and evening in tandem with a progressive shortwave trough over the Upper Midwest. Damaging winds will remain a concern given the linear mode and strength of the low/mid-level flow per area VWPs. There is also some potential for a few tornadoes with embedded circulations within the line, particularly in close proximity to a deepening surface low that will develop from far eastern IA into WI through this evening. For more information on the near-term severe threat across this area, see Mesoscale Discussion 1780. ..Gleason.. 11/10/2020 .PREV DISCUSSION... /ISSUED 1015 AM CST Tue Nov 10 2020/ ...Mid MS Valley... Water vapor loop shows a strong shortwave trough and associated mid-level speed max rotating across the central Plains into MO/IA. This feature will result in strong surface cyclogenesis as a surface low deepens along a cold front extending from northern MO into WI. The corridor along and just east of the low/front will be the area of concern for strong/severe thunderstorms today. Thunderstorms are ongoing this morning along the front over MO. Convection is expected to intensify and build northward toward the surface low by early afternoon. CAM solutions indicate that the bowing convective structures will not be substantially undercut by the front, suggesting the activity will remain primarily surface-based. This supports a risk of damaging wind gusts in the stronger cores. Forecast soundings show strengthening low-level shear across the threat area through the afternoon as the deepening low helps to back/enhance near-surface winds. This could promote the development of a few semi-discrete supercells along the line, posing a risk of a few tornadoes. The activity will track northeastward across Lake MI this evening and eventually into northern Lower MI. Thermodynamic parameters will be rather weak over this area, but there is some potential for a lingering risk of locally strong/damaging wind gusts. ...FL... Relatively strong deep southeasterly flow is present today across the FL peninsula. A moist and moderately unstable air mass is also in place across the region, with broken sunshine this afternoon helping to steepen low-level lapse rates. Local VAD profiles show 25-35 knot winds in the 0-3km layer. Most CAM solutions show relatively fast-moving thunderstorms affecting the region, posing a risk of locally gusty/damaging wind gusts.
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