Enjoy the chill. Sizzling summer temperatures swing into full blast just in time for the solstice

"We hope those of you in the West and also across the Southeast enjoy the cooler temperatures while they last, as more summerlike temperatures will be returning by the end of the week," the Weather Prediction Center tweeted Monday.

The summer solstice is the official start of summer on the astronomical calendar.

Cold air damming on the East Coast

Temperatures will feel more like April than mid-June this week in parts of the Carolinas and southern Virginia. High temperatures will struggle to reach 70 degrees in some places.

Below-average high temperatures will stretch from New York to Florida.

Rain is also a significant concern across the eastern Carolinas, where more rain could fall after days of rain.

"An additional 2 to 5 inches of rain is expected in eastern North Carolina through mid-week with flash flooding also possible," CNN meteorologist Monica Garrett says.

A low-pressure system on the Carolina coast is drawing cooler air from the north and moisture from off the Atlantic. This cooler air pushes up against the Appalachian mountains, which act like a dam holding the air in place. This meteorological phenomenon, called cold-air damming, will lead to the flooding rains and exceptionally cool conditions across the southern Mid-Atlantic.

"The cut-off low over the Southeast is in no hurry to move," Garrett says.

By Saturday, the Southeast will return to average summer temperatures, while the Northeast is likely to swing to slightly above average.

June snow and wildfire danger out West

Meantime, some higher elevations across the Rockies could see snow this week, while fire danger exists further south.

Some areas across Montana and Idaho are under winter storm watches for accumulating snow above 6,000 feet. Snow could accumulate in some areas up to 8 inches, and in some isolated areas, up to a foot is possible.

With prolonged breezy and dry conditions to the Southwest, the National Weather Service elevated its Tuesday forecast to critical fire weather conditions across the region.

Red Flag warnings remain in effect from Nevada to the high plains of eastern Colorado and western Kansas.

Elsewhere across the West, temperatures will remain below average before rebounding Wednesday to average summer temperatures. The cooler temperatures across the Western US are aided by the low-pressure system moving across the northwestern US.

By the end of the week, most of the West Coast will bake in above-average temperatures.

Severe storms are likely as the central US swelters

A cold front over the next couple of days in the country's midsection will lead to severe storms and also ease above-average temperatures.

There's a slight risk for severe storms Tuesday and Wednesday in the Northern Plains, the Storm Prediction Center forecast.

"Damaging winds, hail and isolated tornadoes are possible," Garrett says.

"A brief tornado or two cannot be ruled out," notes the Storm Prediction Center.