Weather across America

(NATIONAL) Pleasant weather continues in the eastern third of the nation as temperatures climb closer to average, a frontal system brings an end to warm and dry conditions, a big warm-up across the Plains as temperatures soar into the 70s and 80s, and daily showers and thunderstorms continue across the Southwest.

Pleasant weather closed out the weekend across the eastern third of the nation, with surface high pressure dominating the pattern, leading to continued cool and dry conditions. Night-time lows may also come close to freezing across higher elevations of the Appalachian region, leading to the issuance of widespread Frost Advisories through Monday morning. Temperatures in the Ohio Valley will gradually rise closer to average and even slightly above-average on Monday and Tuesday, with highs in the mid-70s to low-80s; areas further east in New England and the Mid-Atlantic will remain in the 60s and low 70s. 

Lake-effect rain showers will continue to develop across the Upper Great Lakes and interior Northeast as a weak cold front moves south through the region, bringing gusty winds of 20-30 mph blowing across the warmer Great Lakes water. Higher elevations in interior New England and upstate New York may see some wet snow on Monday morning, though no accumulation is expected.

The next major headline will be the arrival of a front moving onshore the Pacific Northwest on Monday evening, bringing an end to the warm and dry conditions that have been anchored in place by an upper level ridge this past week. Rain will develop over parts of the Pacific Northwest into the Northern Rockies on Monday evening, and by Tuesday, rain (mixed precipitation possible in higher elevations) will be possible over parts of the Northern Rockies and Northern High Plains.

Further east, temperatures continue to be on the uptick across the Plains and Midwest ahead of the aforementioned potent cold front that will sweep through the region midweek, with highs soaring into the mid-70s and low 80s on Monday and Tuesday. Prior to the arrival of the frontal boundary, warm, moist air will surge northeastward into the region, leading to the potential for showers and thunderstorms on Tuesday afternoon and evening.

Daily showers and thunderstorms continue across the Southwest and western Texas on the east side of a lingering upper-level low that is allowing for moisture-rich air to surge northwestward, causing heavy rainfall rates and isolated instances of flash flooding, particularly in areas of sensitive terrain and across burn scars. The threat shifts eastward on Monday into primarily western Texas. Furthermore, high temperatures will remain below normal, with temperatures ranging from the mid-60s to the low 70s.

Elsewhere, a weak front and easterly flow off the Atlantic will allow showers and thunderstorms to develop over parts of southeastern Florida through Tuesday.