Weather across America

(NATIONAL) Much needed rains return to portions of California, heavy rain and flash flooding threat to increase from the Southwest into the Central Rockies, the return of record high temperatures across the Southern to Central Plains into the Lower to Middle Mississippi Valley, and heavy rain, flash flooding and severe weather possible across portions of the Mid-West into the Northeast.

The mid to upper level pattern across the nation will become increasingly amplified over the next several days as a strong upper low spins off the California coast and an expanding upper ridge stretches across the Southern-Central Plains into the Lower to Middle Mississippi Valley. The upper low off the California coast will continue to provide some much needed rains to portions of Northern to Central California, which remain in severe to extreme drought.  

While this rain is much needed, recent wild fires have created burn scars that may result in enhanced flash flood and mudslide risks if heavy rains fall across these burn scar areas. The clouds and rains across California will also support much below average temperatures over much of California through at least the end of the week before temperatures begin to rise back to average levels.

The strong closed low off the California coast will also be responsible for a northeastward transport of much above average moisture values from the tropical east Pacific off the western Mexico coast into the Southwest U.S./Central Rockies region over the next few days. This will support increasing chances of heavy rains and localized flash flooding from the Southwest into the Central Rockies over the next several days.

While weather conditions are expected to be generally cool and wet associated with the strong closed low off the California coast, the opposite will be true from the Southern to Central Plains into the Lower to Middle Mississippi Valley where a strong upper ridge will be expanding. Temperatures are expected to remain much above average across large portions of the mid section of the nation over the next few days.  

Record high temperatures which have been sparse across the lower 48 over the past week will be making a return across the Southern-Central Plains into the Lower to Middle Mississippi Valley with numerous record highs expected through mid week.

To the northeast of the area of potentially record hot temperatures, a surface frontal boundary is expected to push eastward from the Mid-West Sunday night, through the Great Lakes and into the Northeast by the end of the day on Monday.  

This front will likely be the focus for active thunderstorms, initially over the Mid-West into the Ohio Valley Sunday night into early Monday and then later Monday afternoon across northern New York State into Northern New England.  In both regions the thunderstorms will bring the threat of heavy rains, localized flash flooding and potential for severe weather.