12:30 PM, Sunday, January 31, 2016

Get ready for a long snowy period Sunday night through Monday night, and even lingering in some places through Tuesday morning. Some of the coldest weather of the season will be with us at least through midweek.

Here is what this storm is:

A large, moderately organized storm that will produce a long period of snow, mainly light to moderate intensity, but some heavy snow is possible. It’s hard to pin down when the heavy snow might occur, but Monday afternoon or early evening seems most likely. Expect significant impacts to ground and air travel.

Most likely accumulation ranges through Tuesday morning:

1-2 feet: mountains and upper foothills (the high end of that range unlikely north of Boulder County)

10-16 inches: south Denver suburbs (incl. Castle Rock, Littleton, Aurora)

8-14 inches: Colorado Springs, Denver, DIA, Broomfield, Boulder

6-10 inches: Longmont, Lyons, Fort Collins

4-8 inches: Cheyenne, northern Weld County

Considerable blowing snow along and east of I-25

12:55 PM MST, Saturday, January 30, 2016

Saturday-Saturday night:

At noon Saturday the cold front whipped through Cheyenne and quickly took 20 degrees off the temperature.  That front will sweep down the Front Range Saturday afternoon and end our mild spell. Some east-west bands of snow Saturday evening will result in variable snowfall, depending on whether one of those bands forms over your area. Accumulation should range from nearly nothing to around 3 inches where there are bursts of heavy snow. So be prepared for brief winter travel on the roads this evening.

Sunday night through Tuesday morning:

The main storm system will result in deep easterly and northeasterly “upslope” winds and widespread snow. Although the heaviest snow is likely to stay south of Denver, the storm should produce enough snow throughout the Denver-Boulder-Fort Collins region to have significant impacts on ground and air travel Monday. The most intense part of the storm is likely Monday afternoon and evening, but you should be prepared for impacts by daybreak Monday, and possibly lingering into Tuesday morning.

Most likely accumulation ranges beginning Sunday night:

Foothills in the counties of Boulder, Jefferson, Gilpin, Douglas, El Paso, and Teller: 12-18 inches, locally 2 feet near Pikes Peak and the Palmer Divide.

Denver (south and west sides), Castle Rock, Broomfield, Boulder: 8-14 inches

East side of Denver, Longmont, Lyons, Fort Collins: 6-10 inches

Weld County, east side of Fort Collins, Cheyenne: 4-8 inches, watch for blowing snow.

1:45 PM MST, Friday, January 29, 2016

A large storm system from the Pacific will be bring winter back this weekend through Tuesday. Initially the Front Range foothills and plains will be mild on Saturday and turning colder Saturday evening with the main snow likely on Monday and Monday night.

Saturday and Sunday:

Expect periods of heavy snow and blowing snow in mountain areas and high passes along and west of the continental divide, mainly on Saturday. For the Front Range foothills and urban corridor, mild weather on Saturday will be replaced by colder weather Saturday evening through Sunday. Localized snow, or rain changing to snow, may occur Saturday evening. The precipitation is likely to be oriented in narrow east-west bands. Most areas will probably get little or nothing, while a few locations may get a quick burst of snow that produces 1-2 inches. Sunday will probably be a mainly dry but colder day.

Monday-Tuesday:

The main storm system is likely move east across northern New Mexico on Monday into early Tuesday morning bringing widespread snow to the state, especially the eastern plains and foothills. Current indications are that the heaviest snow may stay south of Denver.

South Denver suburbs and southward: most likely range is 6-12 inches with some chance  more depending on exact development of the storm.

Denver-Broomfield-Boulder: at least 3-6 inches, with a 50-50 chance of 6-10 inches, and just a small chance of more than 10.

Larimer & Weld counties, and Cheyenne area: most likely range of 2-6 inches, with a small chance that a northward shift could bring heavier snow.

Expect snowy travel in the urban corridor Monday and Tuesday morning. I will update over the weekend.

12:30 PM MST, Thursday, January 28, 2016

Enjoy some nice mild weather through Saturday afternoon.  Colder weather with a few snowy periods appears likely in the Saturday evening through Monday night period. We may see the most significant snow since the 6-12 inches that fell on Dec 15th.

The mild weather Friday and Saturday may be accompanied by some chinook winds in and near the foothills. An all-out windstorm is not expected, but some warm gusty winds may help erode the remaining ice patches that have been around since the 2nd week of December. For mountain areas near and west of the continental divide, Saturday will likely have increasing cloudiness, snow, and wind as the day progresses.

Saturday night-Monday:

A large, moist storm system from the Pacific will impact the Front Range region in several phases. The first phase Saturday night into Sunday morning is likely to bring significant snow to mountain areas, and some minor snow to the Front Range urban corridor. Then after a lull, the main storm system Sunday night into Monday has the potential to bring widespread snow (in the 6-inch range) throughout the Front Range region.

There is still uncertainty. One model–the European–evolves the storm in a way that would bring the most significant snows to the Front Range region Saturday night, with minor additional snow after that. At this point, I’m leaning toward Sunday night through Monday as the main snowy period for the urban corridor. Either way, be prepared for some changes Saturday evening (earlier in the mountains), and wintry weather into Monday.

11:55 am, Friday, January 22, 2016

While the region around Washington DC braces for a high-impact snowstorm, the Front Range region will enjoy dry and mild weather Saturday into early Sunday. Colder weather with some snow is likely Sunday in the mountains, but not until late Sunday or Sunday night in the urban corridor.

A big storm is not expected, and neither is bitter cold weather. But colder weather with a light coating of fresh snow appears likely for most areas by Monday morning. If you are flying over the next 48 hours, expect delays for any flights coming from or going to Charlotte, Washington DC, Philly, or New York (Boston should be okay). Enjoy the weekend!

12:30 pm, Monday, January 18, 2016

A weak storm system moving through Colorado/Wyoming tonight is likely to bring light snow accumulations to the mountains, and maybe a light coating to some locations in the urban corridor.

If there is accumulating snow along the Front Range, it is likely to be during the night or early morning. But amounts should be minor, ranging from nothing in some places to an inch in others. Another chance for a minor snowfall arrives on Wednesday evening.

Temperatures are not likely to stray far from seasonal averages this week. In fact, this month is averaging a little colder than average, but has lacked notable warm or cold spells.

1:00 PM, Friday, January 15, 2016

Several periods of snow are likely to bring a fresh covering to mountain areas along and west of the continental divide and make for some snowy travel at the high passes.  The best chance or accumulating snow is tonight, and again Saturday evening into Sunday. East of the continental divide in places like Nederland, the amounts should be light.

For the urban corridor there may some areas of light snow tonight and again Sunday, but many areas are likely to stay dry.  Although the chance for up to 1 inch is small everywhere, it’s a little better around Fort Collins & Cheyenne than it is around Denver & Boulder.

Seasonably cold weather is likely through the weekend, with Monday expected to be the mildest of the three days.

2:40 PM, Thursday, January 7, 2016

There has been spotty (mainly minor) snowfall through the Front Range region today and that will continue into the evening. More widespread snow (mainly light) is likely later tonight and early Friday. The best chance for some heavier amounts is in the Palmer Divide region south of Denver.

The storm in question should result in mainly north winds (rather than east or northeast) which reduces the chance for heavier snow in most areas except the south suburbs of Denver and the Palmer Divide. Temperatures should remain below freezing Friday, and probably Saturday and Sunday too, but with drier weather over the weekend.

Most likely accumulations:

Palmer Divide, Castle Rock, south suburbs of Denver: 3-7 inches.

Coloroado Springs, Denver, Broomfield, Boulder, Nederland: 2-4 inches

Longmont, Fort Collins, Cheyenne: less than 3 inches

Mountains areas:

Mainly light snow there too, but heavier amounts (~12″) down south in parts of the Sangre De Cristos and San Juans.

1:00 PM, Wednesday, January 6, 2015

Cloudier and colder weather will arrive by daybreak Thursday, and even colder weather should move in by daybreak Friday and last through Saturday. Areas of snow are likely Thursday. Friday morning is likely to be the period with the most widespread coverage of snow.

Snow: A large, somewhat disorganized storm makes it difficult to pin down the period with the best chances for accumulating snow.

Thursday: The Front Range region is likely to have areas of accumulating light snow by Thursday morning, but due to the lack of upslope (easterly) wind, probably not everyone will get snow. And the best chances are not necessarily in and near the foothills.

Friday: Cold northeast winds Thursday night and Friday will probably increase the chance for light snow accumulations (1-4 inches) over the whole area. There is even the chance for more moderate accumulations of at least 6 inches in some potion of the area. I will update tomorrow, but for now, expect winter travel conditions Friday morning.

Noon, Tuesday, January 5, 2015

After another relatively mild day Wednesday, colder (but not bitter cold) is expected to return Thursday through Saturday. Sometime in that period the Front Range region is likely to get some light accumulation of snow. The storm system involved is large and not well organized so it’s hard to tell when the snowiest periods would be. Much of the time is likely to be dry. Right now it looks like Friday may bring the best chance for widespread snow.

A very cold air mass is expected to move into the north-central United States this weekend. Most indications are that the coldest air will stay east of Colorado. But we can’t yet rule out a very cold spell late in the weekend or early next week.