Severe Storm Risk - Butler, PA

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 MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE EAST AS WELL AS PARTS OF THE SOUTHWEST AND NORTHERN PLAINS SUMMARY Scattered strong to locally severe thunderstorm development is expected this afternoon and evening across parts of the lower Great Lakes and upper Ohio Valley into the middle and southern Atlantic Piedmont. Damaging winds are the primary hazard, although a tornado could occur. Eastern States The large-scale positive-tilt upper trough will continue to drift eastward regionally, with the leading edge of height falls generally parallel to the Appalachians. Ahead of a cold front, early day cloud cover, precipitation, and otherwise generally weak lower/mid-tropospheric lapse rates will be factors that tend to limit overall boundary-layer destabilization. Breaks in cloud cover into this afternoon will eventually allow for widely scattered to scattered intensifying thunderstorm development into mid/late afternoon. This may focus within a pre-cold frontal corridor across the Allegheny Plateau/upper Ohio Valley into lower Great Lakes vicinity, where it could be enhanced by 20-40 kt south-southwesterly flow in the 850-500 mb layer, and within somewhat more modest flow off the higher terrain in vicinity of the lee troughing across the Piedmont. With at least modest CAPE in excess of 1000 J/kg, and potential for heavy precipitation loading in the presence of seasonably high moisture content, localized strong downbursts may generate a few damaging surface gusts. A brief tornado threat may also exist across parts of upper Ohio Valley toward the Mid-Atlantic given sufficient low-level shear/SRH in the presence of a moist boundary layer. North Dakota/northwest Minnesota The extent and likelihood of sustained deep convective development remain uncertain. Some guidance has suggested that there may be at least attempts at deep convective development late this afternoon near the weak pre-cold frontal surface troughing. However, the potential for sustained thunderstorm activity remains unclear due to limited low-level moisture beneath very warm and dry mid-levels, associated with an elevated mixed-layer overspreading the region today. A somewhat better potential for thunderstorm development may await increasing forcing for ascent with the approach of the upstream shortwave trough later tonight. In either case, some risk for hail and severe winds will exist pending development across the region. Southeast Arizona/far southwest New Mexico Residual cloud cover and widely scattered convection should clear relatively early today, with renewed diurnal destabilization across southeast Arizona and nearby southwest New Mexico. At least widely scattered thunderstorms should develop over the mountains/higher terrain of the Arizona/New Mexico border vicinity, with southwestward storm persistence across southeast Arizona aided by moderately strong northeasterly winds. A few instances of severe-caliber wind gusts/blowing dust are possible this afternoon through early evening.