The nation's weather

May 24, 2011 - 4:57 AM

More storms are expected in the East on Tuesday as a low pressure system in southern Canada drags a cold front through the Eastern Valleys.

The cold front will sag across the Northeast and the Ohio Valley through the day and will extend from the Northeast through the Southern Plains by the evening. Rich moisture from the Gulf of Mexico will spread northward and pool along this front, fueling more rain showers, bands of heavy rain and clusters of thunderstorms ahead of this system, especially in the Mid-Mississippi and Ohio Valleys. Meanwhile, cold dry air from Canada will spread southward on the northern side of this front, increasing instability along this boundary. The Storm Prediction Center has put areas from northwestern Texas to southern Nebraska at moderate risk of severe weather development. Areas surrounding this moderate risk area and northeastward, from the Southern and Central Plains through the Ohio and Tennessee Valleys into Southern New York, are at slight risk of severe weather development with large hail, damaging wind, frequent lightning and tornadoes. A tornado outbreak will be possible across the Central and Southern Plains on Tuesday. Residents in these areas are encouraged to monitor their local weather activity through the day and heed weather warnings and advisories.

In the West, low pressure will trigger more showers and thunderstorms in the Northern and Central Rockies. Farther west, a weak ridge of high pressure will allow for brief and slight warming in California. To the north, another disturbance will approach the Pacific Northwest through the day. Showers may reach the coast by late Tuesday night.

Temperatures in the Lower 48 states Monday ranged from a morning low of 26 degrees at Truckee-Tahoe, Calif., to a high of 100 degrees at Childress, Texas.