Canada

Weather Underground Forecast for Sunday, May 18, 2008. A low pressure system will develop in the Ohio Valley and move into New England before tracking to the Northeast coast by the end of the day. This feature will produce considerable rain from the Ohio Valley through New England. Its associated cold front will move across the Appalachians towards the eastern seaboard. As it moves eastward, it will pick up moisture that will instigate rain and thunderstorms from Alabama through the Mid-Atlantic.

Seasonally cold air will move into the Great Lakes, allowing below normal temperatures to persist.

Scattered showers are possible over the peninsula of Florida due to the influence of a lingering frontal system.

An intensely strong ridge of high pressure that has brought record high temperatures to the West for the past several days will continue to blanket the region with very warm temperatures. Some coastal regions will begin to cool off due to the return of the marine layer, but inland areas will continue to be very warm.

The Northeast will rise into the 50s, 60s, and 70s, while the Southeast will see temperatures in the 80s and some 90s. The Southern Plains will rise into the 80s and 90s, while the Southwest will rise into the 90s and 100s. The Northwest will rise into the 70s, 80s, and some 90s.

Temperatures in the Lower 48 states Saturday ranged from a low of 26 degrees at Yellowstone Lake, Wyo. to a high of 113 degrees at Death Valley, Calif.