9:30 AM MST, Sunday, January 20, 2019
A total lunar eclipse will occur this evening beginning and 9:41 PM and lasting until 10:43 PM. There is a lot of upper level Pacific moisture that could result in some cirrus clouds, but it’s worth a look if we are in a clear area at that time
The next Pacific storm will move through late Monday. Snow may begin impacting mountain areas (especially the west side) Monday afternoon, but probably hold off until evening along the Front Range and eastern plains. Once again there is not likely to be much easterly (upslope) flow, so the heaviest snow won’t necessarily be near the foothills. Rather, there is likely to be some north-south gradient with the heaviest along the north-facing slopes of the Palmer Divide.
3-6″ for the mountains and the Palmer Divide region, including Castle Rock and the far south suburbs of metro Denver.
2-4″ for the Denver-Boulder metro.
0-2″ for northern Boulder county and up into eastern Larimer and Weld counties.
2-4″ Cheyenne area
1-3″ Colorado Springs
The snow should be mainly overnight Monday into early Tuesday morning.
Noon MST, Thursday, January 17, 2019
A cold front tomorrow won’t turn the weather terribly cold, but it will be colder than today with some clouds around. It might still be fairly mild in the early morning along the east slopes and high plains. Significant snow will be limited to the mountains and west, so be careful if you are travelling that way tonight or Friday. For the Front Range region, there may be some areas of light snow around Friday, but that best chance for minor accumulation (0-2 inches) is south of Denver.
After a chilly start on Saturday expect a dry weekend with low elevation temperatures returning to the 50s on Sunday.
The next cold front and fast-moving Pacific storm system may start bringing areas of snow to the mountains Sunday night. For the Front Range region, expect colder weather on Monday and there is a better chance with Monday’s storm for some widespread snow developing, at least light amounts.
3:00 PM MST, Friday, January 11, 2019
Intermittent snow is likely into the evening today, mainly along the west and south side of metro Denver and the Palmer Divide. Although additional accumulation won’t be very large, nightfall and temperatures dropping below freezing may cause some accumulation and black ice on roads this evening.
The weekend should be dry and seasonably cold, but perhaps with some air stagnation along the urban corridor.
At 3PM at my home in South Boulder there has been 1.2 inches of snow and 0.54 inches of liquid. That’s a remarkable snow-to-liquid ratio for a January storm. About 0.15 inches of liquid fell as rain early this morning. It’s more like an April storm!
9:00 AM MST, Thursday, January 10, 2019
A weak but intensifying storm will move through the central Rockies on Friday bringing some snow. The snow is likely to be a little wetter than usual for January with a gradient ranging from very little in the plains of eastern Larimer and Weld County, to some moderate amounts (exceeding 6 inches) in the Palmer Divide and foothills.
The most likely accumulation
There is a lot of variability due to the timing of storm intensification and whether there might actually be a little rain at the start. The most likely accumulation is 4-8 inches for the foothills and Palmer Divide area, 2-4 inches for most of the Denver-Boulder metro, 0-2 inches in Longmont, Fort Collins, Cheyenne, and Colorado Springs. The timing is mainly during the day on Friday, possibly beginning by sunrise and continuing into the evening. This outcome has about a 60% chance of occurring.
The low end possibility
The GFS, a reliable U.S. based model, has been consistently showing that the storm won’t really get going until it’s east of Colorado and thus the snowfall should be rather minor. Amounts with this model should range from 3-6 inches in the foothills, mountains, and Palmer Divide regions, 1-2 inches in the Boulder-Denver area and little or nothing in Longmont, Fort Collins, Greeley, and Cheyenne. This outcome has about a 30% chance of occurring.
The high-end possibility
Some of the mesoscale models based on the WRF have been more likely to begin intensifying the storm as it moves east through the central Rockies and tapping some subtropical Pacific moisture as it intensifies. These solutions suggest a 6-10 inch snowfall in the Denver area south of I-70 and extending north along foothills to Broomfield and Boulder. The amounts trail off rapidly to just 1-3 inches for northeast Boulder County, Larimer, and Weld counties. The trend seems to be away from this so this outcome has about a 10% chance of occurring.
Dry weather with seasonable temperatures. The air may be somewhat stagnant, so some haze along the Front Range urban corridor is likely.
9:20 AM MST, Sunday, January 6, 2019
My forecast from yesterday morning hasn’t changed except that the chance for some strong gusty west-northwest wind has increased for the Front Range region and adjacent plains. Today through Monday are likely to see some gusty downslope winds, especially in and along the foothills. The best chance for gusts exceeding 60 mph is on Monday.
Other than that, you should still expect some snowy stretches in the mountains and western Colorado today. There may be a lull tonight and then some additional intervals of snow at the high elevations on Monday. Totals of 6-10 inches are likely at some of the high passes, much less in the valleys.
The Front Range foothills and plains should stay dry with some cloudy intervals and gusty winds. Some sprinkles or flurries will make it as far east as the foothills before evaporating. Despite slightly cooler weather, lower elevations are still likely to reach 50 degrees, which is above average for January.
9:30 AM MST, Saturday, January 5, 2019
A couple of fast moving Pacific storm systems will move across the Rockies Sunday and Monday bringing some snow to the mountains and West Slope areas, but probably nothing much more than some increased cloudiness and slightly cooler weather for the eastern foothills and plains.
The heaviest snow is likely in the higher mountains and west-facing slopes where 6-10 inches could fall mainly on Sunday, but some on Monday too.
Snow shouldn’t make it too far east of the continental divide, but some light accumulations are likely in places like Rocky Mountains Park and Brainard Lake. Although some clouds and cooler weather are likely in the lower foothills and plains, temperatures are likely to remain near or a bit above average. Very mild weather is likely to return by mid-week.