Weather Underground Forecast for Sunday, September 29, 2013.
A strong low pressure system will continue to swing into the Pacific Northwest on Sunday, while a ridge of high pressure will keep the Eastern Seaboard relatively dry.
Moderate to heavy rain will pick up in the Pacific Northwest on Sunday as a slow moving cold front inches into the region. Flash floods will be possible throughout the day, especially along elevated terrain, in Washington, Oregon, and northern California. Even parts of Idaho and western Montana may experience flash flooding as a result of this cold front passage. Parts of the Cascades and northern Rockies will experience heavy snowfall throughout the day. Meanwhile in the southern Great Basin and Southwest, a high pressure system will keep conditions relatively dry. To the east, a cold front will continue to push wet weather through parts of the central and southern Plains, as well as the Ohio River Valley. Spotty showers and thunderstorms will accompany the front, but the strength of the thunderstorms will likely weaken by nightfall.
The majority of Northeast will sit under a ridge of high pressure on Sunday, which will draw cool, dry air in from Canada. Temperatures will likely be in the 60s and 70s during the day for the majority of the Eastern Seaboard. Meanwhile along the coast of the Carolinas and Florida, an onshore flow may draw enough moisture in from the Atlantic to trigger some afternoon showers and thunderstorms. .
Temperatures in the Lower 48 states Saturday have ranged from a morning low of 15 degrees at Wolf Creek Pass, Colo. to a high of 94 degrees at Brenham, Texas