SPC Mar 20, 2017 0600 UTC Day 1 Convective Outlook

By Newsroom America Feeds at 20 Mar 2017

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Mon Mar 20 2017 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible through Monday evening across parts of the Midwest eastward to the Appalachians. Isolated storms are also forecast across parts of the Intermountain West and possibly into parts of the Plains late Monday into the overnight. Finally, an isolated storm or two could occur across parts of West Texas and adjacent southeast New Mexico. ...Synopsis... Large-scale upper ridging across the U.S. will continue to be suppressed on its northern fringe by an upper trough shifting eastward across central and into eastern Canada. As this trough moves eastward, the larger-scale ridging will expand back northward in its wake -- across the Canadian Rockies -- in advance of a second trough approaching the West Coast. At the surface, a cold front will move eastward across the Great Lakes, and southward across central portions of the country as high pressure ridges southward out of Canada. Farther west, trailing portions of this front will linger northwestward across the High Plains and then westward across the Intermountain region through the period. ...The Midwest vicinity... Showers and scattered thunderstorms -- possibly in the form of an elevated MCS -- should be ongoing at the start of the period across parts of the Illinois/Indiana/Ohio area, which should continue spreading southeastward with time toward the central Appalachians. Redevelopment of elevated convection may occur in the wake of the prior storms, across the Illinois/Indiana/Lower Michigan vicinity, as weak disturbances continue moving through fast west-northwesterly mid-level flow. While a few stronger storms -- aided by relatively strong cloud-layer flow and fueled by modest elevated CAPE -- will be possible, at this time it appears that any hail should remain largely if not entirely sub-severe. Farther south, other/more isolated showers and possibly a thunderstorm or two may evolve across the Ozarks vicinity, spreading east across the mid-Mississippi and Tennessee Valleys through the afternoon. ...Parts of the Intermountain West and into parts of the Plains... Short-wave troughing now moving across northern California will aid in increasing afternoon convection -- possibly including a few thunderstorms -- across portions of the Intermountain region during the afternoon and evening, particularly in the vicinity of lingering remnants of the surface front lying across the area. Some of this activity may linger through the evening -- possibly spreading into the Nebraska vicinity after dark. ...Far southeast New Mexico and into western portions of Texas... A high-based storm or two could develop during the afternoon hours across parts of the area, as a weak vort max now crossing northwest Mexico drifts toward far West Texas. ..Goss/Smith.. 03/20/2017 Read more



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