Severe Storm Risk - Ralph, SD

There is a Marginal Severe Storm Risk for your location. Continue reading for today's outlook from the National Weather Service's Storm Prediction Center. -------------------- National Severe Storm Outlook THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING ACROSS PARTS OF THE SOUTHERN TIER OF NEW YORK INTO NORTHERN AND CENTRAL PENNSYLVANIA SUMMARY Thunderstorms posing a risk for potentially damaging wind gusts may continue into late evening across parts of the Southern Tier of New York into northern and central Pennsylvania. Great Lakes into Mid Atlantic To the south of a modest lower/mid-tropospheric cyclone, now migrating to the east of James Bay, the leading edge of broad mid-level troughing is in the process of gradually shifting east-southeast of the lower Great Lakes region. Forcing for ascent associated with this feature has contributed to the evolution of an organizing cluster of storms now spreading across western New York state, ahead of a southward advancing segment of the surface frontal zone trailing the cyclone. However, in the wake of an early day convective cluster, appreciable warm sector boundary-layer instability is becoming confined to a narrowing corridor across the Allegheny Plateau. As the ongoing convective system continues east-southeastward, and the onset of boundary-layer cooling progresses, more stable southeasterly near-surface updraft inflow seems likely to weaken convection and reduce the associated risk for severe weather as it spreads toward northern Mid Atlantic coastal areas tonight. Upstream, convection-allowing guidance suggests that forcing for ascent associated with lower/mid-tropospheric warm advection may support renewed widely scattered thunderstorm development overnight. This is mostly likely to focus near/to the cool side of the stalling trailing frontal zone on the southern fringe of the westerlies, across southern portions of the Great Lakes into Upper Midwest. Aided by modest strengthening of westerly flow in excess of 30 kt around 850 mb, and steep lapse rates of lower/mid-tropospheric temperature and potential wet-bulb temperature, there appears potential for one or two upscale growing clusters which may pose a risk for severe hail and wind. Northern Rockies and adjacent Great Plains The risk for severe weather has diminished considerably in the wake of weakening convection now overspreading the Montana international border. As the supporting vigorous short wave impulse continues to pivot north of the border into the Canadian Prairies this evening, this appears unlikely to change. An isolated strong storm to the east-southeast of Miles City MT does appear supported by updraft inflow of relatively moist boundary-layer air characterized by sizable CAPE in excess of 2000 J/kg. However, it is not clear how long this will be maintained, as inhibition increases with boundary-layer cooling and perhaps some further warming aloft.