A late spring storm system will bring more wet and windy weather to the West this Memorial Day.
A mix of rain and wet snow with thunderstorms will continue over parts of the Northern Intermountain West, Central Great Basin and the Northern and Central Rockies. Heavy wet snow in the higher elevations will reduce visibilities, making travel conditions difficult for those outdoors. Meanwhile, periods of heavy rain and recent snow melt will raise more flood concerns in parts of the Northern Intermountain West. To the south, gusty winds, warm temperatures, and low relative humidity values will maintain fire weather conditions in the Southwest.
To the east, the low pressure system in the Central Rockies will lift into the Northern Plains on Monday while it's associated warm front lifts northward into the Northern Plains and the Upper Great Lakes. Showers, periods of heavy rain and thunderstorms will form to the north of this boundary in parts of Upper Midwest. There is a moderate risk of severe thunderstorm development from southeastern North Dakota, eastern South Dakota, northeastern Nebraska into much of west-central/southwestern Minnesota and northwestern Iowa. Severe storms in these areas may produce very large hail, damaging winds and a few strong tornadoes. There is a slight risk of severe thunderstorm development surrounding the moderate risk area from the eastern Dakotas and Minnesota southwestward to the Southern Plains. While the primary threats with severe storms in these areas will be large hail and damaging wind, tornado formation may be possible.
Elsewhere, a weak cold front will move through the Northeast with scattered showers and thunderstorms. Meanwhile, Memorial Day will likely mark the start of the first heat wave of the season for the Delaware Valley. Daytime highs in the area will climb into the 90s and heat indices are expected to reach near the century mark through the mid-week.
Temperatures in the Lower 48 states Sunday ranged from a morning low of 24 degrees at Truckee-Tahoe, Calif., to a high of 106 degrees at Pecos, Texas.