SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1017 PM CST Fri Dec 11 2020 Valid 121200Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Only minimal thunderstorm activity is anticipated today over parts of the contiguous United States. ...Synopsis... A strong mid-level shortwave trough will quickly move from the mid MS Valley northeastward through the Great Lakes during the period. An attendant surface low will develop northeast from northwest IN through lower MI during the day and reach the Ontario/Quebec border by early Sunday morning. A cold front will extend south from the surface low and sweep eastward across the OH Valley and Mid South with the front weakening across the central Gulf Coast. ...Southern Great Lakes... The northern portion of a narrow warm sector will extend north into IN ahead of the surface low. Models indicate low 50s F dewpoints as far north as northeast IN/northwest OH during the late morning. Forecast soundings show very cold 500 mb temperatures (-22 deg C) with a mid-level dry slot protruding northeast into the southern Great Lakes by the late morning. Models differ regarding the magnitude of destabilization but it seems temperatures may warm to at least low to mid 50s. The strong wind profile may conditionally support a few low-topped cells. If cloud breaks or appreciable heating can materialize, a localized threat for strong gusts could accompany the strongest cells---primarily during the late morning to early afternoon. A few thunderstorms are possible mainly during the morning through the mid afternoon across the central Gulf Coast states before this activity diminishes by early evening. Weak instability will probably limit storm intensity and the prospects for an isolated damaging gust. ..Smith.. 12/12/2020
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