2PM Day 3 Convective Outlook for Friday, June 27. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE NORTHERN PLAINS
SUMMARY
Severe storms producing large hail and locally damaging winds are forecast over parts of the northern Plains late on Friday. Sporadic damaging gusts may also occur over parts of the Mid Atlantic and Southeast.
Synopsis
A broad mid-level trough will shift east across the northern Rockies on Friday with strengthening mid-level flow overspreading the northern Plains. This will result in lee troughing from the Canadian Prairies to the central High Plains. A moist environment will be in place east of this trough with dewpoints in the 60s.
Northern Plains
Moderate to potentially strong instability is forecast across the northern Plains on Friday with temperatures near 80 and dewpoints in the 60s. Strengthening mid-level flow should result in ample shear for supercells by Friday afternoon/evening as ascent increases across the northern Plains. Significant hail and severe wind gusts will be the primary threat from this activity. A strengthening/moist low-level jet may support supercell maintenance through the evening and perhaps into the overnight period. Even if diurnal storms dissipate, additional overnight elevated storms are likely across portions of eastern North Dakota and northern Minnesota amid strengthening isentropic ascent.
Mid Atlantic to the Southeast
Moderate instability is expected to develop across much of the eastern CONUS on Friday. Instability is not expected to be as strong as mid-level temperatures will be warmer after Day 1/2 convection across the region. However, a pocket of relatively cooler air aloft will exist across the Southeast and into the central Appalachians and Mid-Atlantic which will support some threat for stronger storms capable of damaging wind gusts.