Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0336 AM CDT Tue Jun 25 2019 Valid 281200Z - 031200Z ...DISCUSSION... At least some severe threat could continue across parts of the northern Plains into the Upper Midwest on Day 4-5/Fri-Sat. Guidance varies, but the overall trend maintains a strong upper ridge over the Plains/Upper Midwest vicinity through at least the weekend. Meanwhile, a trough may persist over the Pacific Northwest. Ample moisture and instability will exist beneath the ridge into the Dakotas and MN/WI vicinity, though deep-layer flow will weaken some with time or be shunted northward into Canada. Additional uncertainty exists due to previous days' storms and subsequent evolution of those potential MCSs, precluding severe probabilities at this time. Additional strong to severe storms could develop across parts of the Great Lakes to the Mid-Atlantic on Days 4-5/Fri-Sat as well. An upper low over Hudson Bay Friday morning will shift southeast across the Northeast/Mid-Atlantic region by Sunday morning. The airmass ahead of this feature should be relatively moist and unstable. Depending on the evolution of prior days' convection upstream across the northern Plains/Upper Midwest, severe potential could be increased by any MCVs or remnant outflow that migrates into the region. Additionally, timing of shortwave impulses as the trough overspreads the region and the accompanying surface cold front leads to too much uncertainty to introduce probabilities at this time. Beyond Day 5/Sat, guidance varies considerably and confidence in organized severe convection diminishes rapidly.
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