Monthly Archives: November 2015

Friday: Brief cold snap, some snow possible

1:00 PM, Thursday, November 19, 2015

A cold front from the north on Friday will bring the coldest air of the season late Friday and early Saturday, but really not that unusually cold for November. A brief period of snow is possible following the cold front.

 

The cold front is likely to reach Cheyenne Friday morning and is expected to move south through the Front Range and eastern plains of Colorado during the late morning through afternoon hours. An hour or two of snow will probably occur in most but not all areas during the late afternoon or evening. Amounts should be light, 0-1 inch in the lower elevations, with a small subset of the area receiving about 2 inches. The higher foothills are more likely to see 1-3 inches, with around 6 near the continental divide.

 

The weekend should be dry but with a cold start on Saturday (teens in the Denver-Boulder area) and then milder by Sunday.

 

It appears that a large storm west of Colorado next week will probably not have a major impact on the Front Range, but I’ll be watching because whatever impact there is may be on Thanksgiving Day. If you are driving west for the holiday next Tue-Thu, pay attention to forecasts in mountain areas from northern Utah to northern California.

 

Many areas of the Front Range (especially north of Denver) have had an unusually high proportion of rain this month given that November is a month that usually sees most of the precipitation fall as snow. In Boulder the average November produces 1.23″ of moisture and 13.3″ of snow. This month we are up to 1.16″ of moisture but only 1.8″ of snow.

Different scene from one side of Denver to the other

6:40 AM, Tuesday, November 17, 2015

Winds gusting to 60 mph and anywhere from 4-12 inches of snow will hamper the morning commute on the south and east sides of Denver. Amounts go down as you move north and west through Denver, with little or nothing in Boulder and Fort Collins. I expected the south and east sides of Denver to get hit the hardest, but the contrast with locations north of Denver is impressive.

 

A few remaining areas of snow should dissipate this morning with some gusty winds continuing, especially out on the eastern plains. The next chance for snow is Friday, but that’s looking pretty minor.

 

 

UPDATE: focus of storm shifts back toward Front Range

6:15 AM, Monday, November 16, 2015

The trend keeping the worst impacts of the winter storm on the eastern plains of Colorado has shifted a bit, and the Front Range, especially the Denver area, appears to be more at risk for major impacts from snow and wind tonight.  The highest impact area is still likely to be the southern and eastern suburbs of Denver (including DIA) and the eastern plains.  But some significant impacts appear possible in other parts of the Front Range Monday night as well.

The storm is likely to begin its intensification while in southern Colorado Monday evening, which is a more favorable location for northeasterly upslope flow along the Front Range.

Timing: Some precipitation, perhaps rain, should be around Monday afternoon. Snow is likely Monday evening into Tuesday morning, lingering longer on the eastern plains and at DIA. Considerable blowing snow is likely (especially east of I-25).

Amounts:

Denver (east and south sides), Palmer Divide region, eastern plains of Colorado: at least 6 inches, up to 12 inches in the Palmer Divide region and parts of the eastern plains. Blowing snow. Expect major travel impacts on the roads and at the airport.

Denver (northwest side), Broomfleld, Boulder: 4-7 inches, mainly during Monday evening and overnight.

North of Boulder (Longmont, Fort Collins, Cheyenne): 1-4 inches. Some blowing snow.

Mountains (Nederland): 4-8 inches , up to 12 at the high passes.

Colorado Springs: 3-6 inches north side, less on the south side. Blowing snow.

I will not be in a position to update with the morning guidance. Bottom line, be prepared for winter travel conditions beginning this evening. Major impacts possible by Tuesday morning, especially the south and east sides of Denver.

High-impact Front Range snowstorm not expected

10:00 AM, Sunday, November 15, 2015

The strong storm system for Monday evening into early Tuesday is evolving in a way that should result in a low-impact storm for most of the Front Range region. Most areas should see under 6 inches, some areas much less than 6. The eastern plains and the Palmer Divide region (south of Denver and north of Colorado Springs) are likely to see the worst impacts of wind and snow.

The storm will be intensifying as it reaches eastern Colorado late Monday night. Such a position results in north winds which are not conducive to long-duration heavy snow along the Front Range. The worst impacts are likely to shift east quickly

Timing: late afternoon/early evening Monday through Tuesday morning.

Most likely accumulation:

South Denver area through the Palmer Divide region, and the plains east of Denver: 3-7 inches, with considerable blowing snow. Expect winter driving conditions.

Denver & west suburbs north through Cheyenne (including Boulder and Fort Collins): 1-4 inches mainly before sunrise Tuesday.  DIA may see snow and wind last longer than the western suburbs.

Mountains: 4-7 inches around Nederland and Estes Park, possibly a little more in the higher mountains.

Colorado Springs: 1-3 inches.

Chance for BIG snowstorm decreasing

12:00 noon, Saturday, November 14, 2015

The storm this coming Monday evening into Tuesday is not taking shape in a way that gives me high confidence for long-duration, high-impact blizzard for the Front Range mountains and urban corridor. It’s not out of the question yet, but right now it appears that the storm will be more of a nuisance type rather than a paralyzing blizzard. Either way, prepare for a change back to more wintry weather late Monday into Tuesday. This storm may be another in the current pattern that causes a bit more impact on the  eastern side of Denver and the eastern plains.

I’ll update Sunday (possibly not until evening) regarding the chances for a big storm.

Nice weekend; snowstorm next week

12:00 noon, Friday, November 13, 2015

After a mild and dry weekend, forces are shaping up for a change to more wintry weather late Monday, and possibly a major winter storm Monday evening through Tuesday from Colorado Springs north to Cheyenne.

Chances are increasing that a strong storm system will move into the four corners region Monday night and then into the high plains Tuesday.  This can be a favorable setup for Front Range snowstorms. As of today, the European and Canadian forecast models move the storm steadily through and keep the snow focused mainly on Monday night and early Tuesday with modest amounts for the urban corridor (6 inches or so). The U.S. GFS model has a large and more slowly evolving storm across southern Colorado and would result in a more prolonged period of snow with high-impact heavy accumulations (well over a foot) Monday evening into Wednesday.

Specific track and evolution details of the storm are still in question, and I will have updates later in the weekend.

Snow late tonight; worse impacts east of Denver

12:45 PM MST, Tuesday, November 10, 2015

A powerful storm will move fairly quickly through Colorado tonight and intensify as is moves to the southeast of Denver. The Front Range region north of Colorado Springs is likely to get a period of moderate or heavy snow in the predawn hours on Wednesday, but it is not likely to last very long and should be tapering off from west to east by around daybreak. Farther east the snow and wind is likely to linger into the morning creating difficult driving conditions on I-70, I-76, and I-80 as you go toward Kansas and Nebraska. DIA and the far eastern suburbs of Denver might see more prolonged snow and wind than most of the Denver area, so be prepared for flight impacts at the airport.

Initial snow may begin this evening in the high elevations. For the lower elevations of the Front Range, there may be some showery rain or snow after dark, but the most intense part of the storm is likely between midnight and daybreak. Most likely accumulations:

Front Range mountains: 3-6 inches Pikes Peak, Nederland and Estes Park, probably up to 10 inches closer to the continental divide north of I-70.

Front Range urban corridor (Denver, Boulder, Fort Collins): highly variable 1-5 inches.

High plains and Cheyenne area: 3-6 inches with low visibility from blowing snow.

Colorado Springs: 1-3 inches north and west sides, probably little or nothing downtown and at the airport. Blowing snow along the Palmer Divide.

Wind: Although the initial round of snow and wind should end tomorrow, a blustery northwest wind is likely to redevelop at times in and along the Front Range into Thursday.