Flash Flood Watch issued July 21 at 2:52AM MDT expiring July 22 at 12:00AM MDT in effect for: Archuleta, Delta, Dolores, Eagle, Garfield, Gunnison, Hinsdale, La Plata, Mesa, Moffat, Montezuma, Montrose, Ouray, Pitkin, Rio Blanco, Routt, San Juan, San Miguel
DENVER - Warm, windy and dry conditions cover eastern Colorado this afternoon. Temperatures are in the 60s to near 70 degrees and the winds are becoming strong and gusty from the west-southwest. The relative humidity is in the single digits and teens. A Red Flag Warning is in effect until 8 PM for the eastern plains as a result of the high fire danger.
In the mountains, clouds are rapidly increasing as the next cold front moves in from Utah and Wyoming. Snow will develop in the next few hours and the winds will be shifting to the northwest late in the day. Snowfall will be about 4-8 inches over the northern and central mountains by Tuesday morning - especially for areas along and west of the Continental Divide. A Winter Weather Advisory is in effect for the central and northern mountains through Tuesday morning.
The wind will be the main feature of this cold front for Denver, the I-25 Corridor and the eastern plains. The strong southwest winds ahead of the front have created areas of blowing dust and an increased risk for wildfire. The strong northwest winds behind the front will also bring some blowing dust and will feature gusts to 50-60 mph on the northeast plains Monday night and early Tuesday.
The front will move quickly, but there will be some precipitation for the northeast quarter of the state. The wind direction will mainly be from the north-northwest and that is mostly a down-sloping wind for most areas east of the mountains. Down-sloping winds tend to dry out, so only light rain and snow is expected tonight and Tuesday.
This storm system is a pretty dynamic one - meaning that the jet stream above Colorado is strong and turbulent. This type of strong wind aloft can sometimes overcome the down-sloping surface wind and actually bring several inches of snow to the eastern plains. Frankly, it makes the forecast for Denver and the northeast quarter of Colorado pretty tricky!
The strong jet stream may help to produce some snow squalls over the northeast quarter of the state for late tonight and Tuesday. I would not rule out a 1-3 inch accumulation of snow, especially for areas just to the northeast of the Denver Metro area - extending along I-76 all the way to the Nebraska border.
The Monday evening commute will be fine for lower elevations, just windy and partly cloudy. By Tuesday morning, roads will be snow covered in the mountains, scattered snow covered in the foothills and range from wet to occasionally snow covered and slippery from Denver north to Cheyenne and east to Nebraska and northwestern Kansas.
Sorry that we can not be more definitive on the exact conditions for the northeast plains on Tuesday, but these strong jet stream driven storms are some of the most difficult to really pin down. Stay with 7News and our Storm Shield App and we will continue to fine tune this forecast.
Skies will quickly clear Tuesday afternoon and evening as the front races to the east of our state. This storm system will evolve into another nasty weather-maker for the Mississippi Valley and the Northeast in the next 2-3 days. A long, tough winter for sure for those folks!
The weather will warm up again Wednesday and Thursday, before the next fast moving cold front arrives on Friday and Saturday. This next front will be similar with more snow for the mountains, strong winds and a chance for rain and snow for the plains.