Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 AM CDT Fri Jul 03 2020 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN HIGH PLAINS/NORTHERN PLAINS...AND SOUTHWARD TO THE CENTRAL HIGH PLAINS... ...SUMMARY... Isolated strong/severe storms will be possible Saturday from the northern Intermountain region east across the north-central U.S., and southward to the central High Plains. ...Synopsis... Upper ridging is forecast to extend from the Southwest northeastward into the Upper Midwest early Saturday morning. Enhanced southwesterly flow aloft will likely be in place between this ridge and the upper troughing expected from southern British Columbia to off the Pacific Northwest coast. Most of the eastern CONUS will be characterized by weak flow aloft surrounding a broad upper low centered near the central Gulf Coast. Surface pattern will likely be void of any well-defined synoptic boundaries, although some more mesoscale, precipitation-related boundaries are possible. In general, the surface pattern will be characterized by a belt of higher dewpoints extending from the Southeast states northwestward through the MO Valley into the eastern Dakotas. ...Northern Plains/Northern High Plains... Showers and thunderstorms may be ongoing across the western Dakotas early Saturday morning as storms that initiated earlier farther west across MT move into the region. Enhanced low to mid-level southerly/southwesterly flow and ample low-level moisture will act to support these storms and an isolated severe potential through the late morning. There is some chance for either reinvigoration of these storms or new development later into the afternoon near an associated vorticity maximum into the eastern Dakotas. However, mesoscale nature of this overall scenario leads to considerable forecast uncertainty, regarding both location and intensity of any storms. As such, elected to keep low severe probabilities with this outlook. Farther west, a subtle shortwave trough embedded within the southwesterly flow aloft is expected to interact with a diurnal destabilized airmass across central MT Saturday afternoon. Convective initiation is anticipated, but the overall storm coverage will be largely influenced by the extent of low-level moisture and potential convective inhibition. Deep southwesterly flow aloft and resulting long hodographs suggest supercells are possible with an attendant threat for large hail and damaging wind gusts. Higher severe probabilities maybe needed in later outlooks if higher storm coverage appears more likely. ...Central High Plains... Convergence along the lee trough combined with ascent attendant to any weak vorticity maxima embedded within the upper ridge is forecast to contribute to convective initiation along the Front Range Saturday afternoon. A few of these high-based storms may become strong enough to produce hail and/or damaging wind gusts. ...Southeast... Scattered to numerous thunderstorms are anticipated during the afternoon and evening as weak ascent around the upper low interacts with very moist air mass. Weak shear is expected to result in predominantly non-severe pulse storms. ..Mosier.. 07/03/2020Read more
from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_0600.html
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