The Nation's Weather 11.21.09

By WEATHER UNDERGROUND (AP)

Heavy rains was forecast to continue over the Gulf States on Saturday while the Pacific Northwest was expected to see scattered precipitation.

A strong low pressure system that developed over the Southern Plains continued to spin over the western Gulf of Mexico. Flow around this system was expected to continue picking up moisture from the Gulf, spreading wet conditions over eastern Texas and Louisiana and into the Florida Panhandle. Flooding was expected to remain a threat over the Lower Mississippi River with coastal flooding due to the slow-moving system producing between 1-2 inches of rain. Periods of heavy rain were forecast in areas of thunderstorm development. Cool conditions were expected to persist with highs ranging in the 60s over the South.

To the North, a large area of high pressure was predicted to continue building over the Plains and Mississippi Valley. This ridge was also expected to spread over the Great Lakes and into the Northeast. Mild weather and warm fall conditions were expected with highs in the 50s. An air quality advisory was to remain in effect over the Upper Midwest as this high pressure acts to trap air and pollutants near the surface.

Meanwhile, in the West, low pressure just off British Colombia was due to continue pushing a cold front over the Pacific Northwest and Northern Rockies. At the same time another cold front was forecast to rapidly approach the coast from the Pacific. Light, scattered showers were expected to persist with up to an inch of rain, with high elevations of the Northern Rockies and Cascades seeing between 3-5 inches of new snowfall.

Northern California was also forecast to remain cool with highs in the 50s, but precipitation was not expected Saturday.

Temperatures in the Lower 48 states Friday ranged from a low of -7 degrees at Laramie, Wyo. to a high of 86 degrees at Miami.