Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0238 AM CDT Mon Jul 13 2020 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY VICINITY AND OVER THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible Wednesday afternoon and evening across portions of the mid-Mississippi Valley, and across parts of the central High Plains. ...Mid-MS Valley vicinity... An upper trough will be centered over the north-central U.S. early Wednesday morning. A shortwave impulse embedded within the larger-scale trough is forecast to eject east/northeast from the central Plains to the lower Great Lakes through the period. At the surface, a weak low will track from eastern IA to lower MI by Wednesday evening. A cold front will shift east/southeast as this occurs, extending from near northwest OH into southern MO and then along the OK/KS border by Thursday morning. A seasonally very moist boundary layer will reside ahead of the front, and strong to severe storms appear possible from eastern KS into the mid-MS Valley and southern Lake Michigan vicinity. There is some uncertainty in how widespread the severe threat may be, and how it will eventually evolve, due to ongoing convection during the morning as the remnants of whatever MCS develops in the Day 2 period across IA/WI will likely be overspreading parts of the mid-MS Valley early Wednesday. For this reason, will only introduce Marginal probabilities at this time, but an upgrade to Slight risk could be needed in subsequent outlooks as mesoscale features become better resolved, and as confidence in the timing of the cold front increases. ...Central High Plains... A weak surface low will reside near the OK/TX Panhandles on Wednesday, with weak post-frontal upslope flow expected on the backside of the low across western KS into eastern CO/NM. This will allow 60s F dewpoints to spread westward across the High Plains. Strong heating and steep lapse rates should result in weak to moderate destabilization by peak heating. A rather stout capping inversion is depicted in forecast soundings across far eastern CO into KS and the OK/TX Panhandles, and this should limit thunderstorm coverage and eastward extent. Nevertheless, isolated thunderstorms are expected through the evening hours across parts of the area, but may remain closer to the higher terrain. These storms will mainly be capable of strong gusts and hail and should weaken with eastward extent during the evening as they encounter increasing inhibition. ..Leitman.. 07/13/2020Read more
from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html
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