In the East, the low pressure system over the Mid-Atlantic will slowly move northward over the next few days before it moves offshore Friday night or Saturday.
This will result in prolonged rainfall especially in northern Mid-Atlantic and southern New England as the system continues to pull moisture from the Atlantic, which will also increase flood threat. Otherwise, expect rain and scattered thunderstorms to continue from the Ohio Valley and Mid-Atlantic to New England, with a few severe storms possible from Pennsylvania to southern New England and Virginia into Thursday.
Out West, the coast, except southern California, will finally get a break from the recent rain Wednesday as the Pacific storm system continues to advance eastward. Strong Pacific moisture ahead of the system will lead to rain and high elevation snow with scattered thunderstorms from southern California eastward across the Great Basin into the Plains. In addition, windy conditions are expected over portions of the Desert Southwest and southern High Plains, with 20 to 30 mph southwest winds and gusts around 45 to 50 mph. Temperature-wise, much cooler temperatures are expected over the next few days across the interior of the West. Highs can be as low as 15 to 25 degrees below normal.
Temperatures in the Lower 48 states Tuesday ranged from a morning low of 23 degrees at Stanley, Idaho, to a high of 94 degrees at Pecos, Texas.