The cold front associated with the storm system in eastern Canada will continue to advance eastward across the Great Lakes and Ohio Valley then onto the East Coast by Wednesday evening.
Expect showers and thunderstorms to continue along and ahead of the cold front. A risk of severe thunderstorms is expected across parts of the Middle and northern Atlantic coast states, with damaging wind gusts and large hail. The southern portion of the front will lift north into the Central Plains on Wednesday. As the front interacts with the Gulf moisture, more showers and thunderstorms are expected again Wednesday. Some may be severe.
Out West, an unseasonably cold trough of low pressure will move eastward gradually across the Western U.S. on Wednesday and Thursday. This will result in continued cold temperatures and unsettled weather conditions across much of the West. Moderate to locally heavy precipitation is possible in the Northwest, Northern California and northern Intermountain West.
Elsewhere, a weak trough of low pressure off the Southeast Coast will support a few showers and thunderstorms over portions of the Southeast. Moreover, some showers and thunderstorms are possible over the southern High Pains, mainly in the afternoon and evening.
Temperatures in the Lower 48 states Tuesday ranged from a morning low of 21 degrees at Bryce Canyon, Utah, to a high of 102 degrees at Frederick, Md.