Monthly Archives: January 2017

Colder Wednesday-Friday

12:35 PM, Tuesday, January 31, 2017

The mild weather pattern will continue for the high mountains and areas west of the continental divide. But for the Front Range lower foothills and plains February will start much colder than January is ending.

 

A cold front is in northeastern Wyoming right now and will ooze into Colorado tonight or Wednesday. The cold air is shallow and may not even make it all the way to Nederland, but for the lower foothills and plains it will be hard to dislodge before Saturday. It’s not bitter cold but it will likely be at least 20 degrees colder than Monday and Tuesday.

Clouds an a dusting or light snow and/or freezing drizzle is likely around Cheyenne where the cold air will be a little deeper. For the Colorado Front Range region there will probably be some intervals of low stratus clouds and maybe a bit of fog or drizzle. But those clouds may dissolve away from time-to-time as well.

Mild, Chinook Winds Possible

3:45 PM, Sunday, January 29, 2017

It should be a mainly dry and mild week coming up across Colorado and southern Wyoming, but with the possibility of some strong gusty Chinook wind in and near the foothills early in the week. It’s difficult to pinpoint the period of time when Chinook winds are most likely. There is some possibility for sporadic gusty winds through the entire early to midweek period. But Monday night or Tuesday appears to be when the chance of 50 mph or greater gusts is greatest for areas near the foothills.

 

Ice from today’s freezing drizzle lingers

3:30 PM, Tuesday, January 24, 2017

Last night’s cold front had an extra push early this morning out of the northeast that resulted in low clouds, ice fog, and freezing drizzle, especially in and along the lower foothills. A mere 0.03 fell here at the NCAR Center Green Campus, but that was enough to make for some ice buildup. Although the drizzle is mainly over, the low clouds and fog have prevented evaporation, so the icy conditions should persist tonight. There may even be a few flurries to add a dusting on top of it this evening.

 

Drier for tomorrow, but a relatively cold week is in store.

A few showers this evening, Colder Tuesday

11:35 AM, Monday, January 23, 2017

A strong low-pressure system should pass by to the north of Colorado this afternoon and evening. Snow should continue in many mountains areas with blowing snow at the passes. At least light accumulations will reach into the foothills for places like Nederland and Estes Park.

Along the lower foothills and plains the significant snow is likely to stay north of Cheyenne, with lighter accumulations and a blustery wind probable in the Cheyenne area. For Fort Collins-Boulder-Denver-Colorado Springs and the adjacent lower foothills, a few showers (rain or snow pellets this afternoon and snow this evening) will likely affect some areas this afternoon and evening. Little or no accumulation is expected. Expect it to be about 15 degrees colder on Tuesday.

Weekend: some snow mountains, mainly dry & seasonably cold along Front Range

12:45 PM, Friday, January 20, 2017

The title says it all. A weak storm is likely to bring some snow to mountain areas (especially across southern Colorado) on Saturday, but the Front Range lower foothills and plains should be mainly dry and seasonably cold. Generally quiet weather should be in place on Sunday with snow returning to some western mountains areas on Monday.

A storm system Tuesday should bring a snowy period in the mountains late Monday and Tuesday. For the Front Range lower foothills and plains it appears that the center or Tuesday’s storm may pass across southern  Wyoming keeping Colo Springs-Denver-Boulder-Cheyenne on the drier side. But it’s still one worth watching.

 

 

Some snow Sunday night and Monday

1:00 PM, Sunday, January 15, 2017

A storm is moving east through southern New Mexico Sunday and will then move northeast into Kansas on Monday. It is causing winter precipitation across southern Colorado that will spread into the eastern plains. At 1PM the leading edge of light snow had been affecting Colorado Springs for hours and was slowly moving into the south and east sides of Denver.

Impact from a secondary storm

A storm on this track would typically keep its impact mainly east of the Front Range urban corridor. A secondary disturbance in Colorado Sunday night may enhance the westward expansion of the snow by Monday morning. Our reliable larger scale models (like the GFS) still suggest very little impact for the Front Range urban corridor, but a few local models are more snowy by Monday morning. Although the local models are better at resolving the influence of the mountains, they don’t always get the atmospheric features correctly so I don’t have high confidence in those solutions.

 

Most likely impact this evening

Some intervals of light snow or flurries are likely, especially the south and east side of Denver (including DIA) and Colorado Springs. Expect less than 1 inch, but maybe 1-2″ south and east of downtown Denver. Difficult travel should be expected near the New Mexico and Kansas borders.

Most likely impact late tonight and Monday along Front Range urban corridor

20% chance of little or nothing

70% chance of 1/2-2 inches

10% chance of 2-5 inches

Difficult travel likely near the Kansas and Nebraska border areas

 

 

Snow for the evening commute

10:00 AM, Thursday, January 12, 2017

A weak frontal passage this afternoon is likely to increase clouds and drop the temperature a bit from Denver northward. Most indications over the last few days are for no precipitation in the lower foothills and plains. But this morning’s runs of some local scale models (like the HRRR) suggest a period of snow (even some brief moderate or heavy intensity) likely in the Denver-Boulder-Fort Collins corridor following the wind shift to east-northeast. Model forecast accumulations are relatively minor (1-4″) but the timing would make the afternoon/evening commute messy. Given these latest models (and my underforecasting bias in a couple recent snowfalls) I’d say snow is likely this afternoon/evening in the Denver-Boulder-Fort Collins area, but much less less likely in Colorado Springs.

 

The holiday weekend is likely to bring relatively tranquil weather Friday and Saturday, but a storm passing to the south and east of Colorado will likely bring winter precipitation to southern Colorado and the eastern border areas late Sunday and Monday. For the Front Range from Denver northward the impact of that late weekend storm is less certain, but it appears not to be a significant weather maker at this time.

 

 

More wind Front Range, more snow mountains

6:20 AM, Tuesday, January 10, 2017

The fierce winds along the Front Range have relaxed in most areas during the night, but this afternoon and evening may see a re-strengthening of chinook winds in local areas in and along the foothills. Many locations will probably see at least a period of gusts over 30 mph and a few local areas may see gusts over 70 mph. On Wednesday the tendency for strong winds will be decreasing, and a cold front may slip into the area by evening. Thursday and Friday are expected to be colder, with just a small chance for snow Thursday.

 

The bounty of snowfall in the mountains continues, along with some rain and even freezing rain in some western valleys. Snow and wind should continue to make difficult travel conditions at the high passes into Wednesday, and intervals of mountain snow may continue through the week.

Mild & Windy Front Range, Snow and Rain West Slope

11:30 AM, Sunday, January 8, 2017

Mild weather, but windy near the foothills, will start the week. Watch for localized gusts over 60 mph. We do have a Pacific cool front coming on Tuesday, but it will only make it a little cooler. The next chance for cold weather will be at the end of the week.

 

Pacific moisture will result in snowy periods (rain in the lower elevations) for the West Slope through Tuesday. Prepare for winter driving if you are heading over the high passes. Some of the moisture will cross into the Front Range region as snow showers for the higher foothills and mountains. A few flurries or sprinkles might make it to the plains near the foothills, but for the most part it should be dry in the lower foothills and plains.

Milder weather coming; recap

12:00 noon, Friday, January 6, 2017

After a cold start on Saturday, temperatures should rebound. Temperatures in the Front Range urban corridor should approach freezing on Saturday, 50 on Sunday, and get well into the 50s on Monday but with increasing chances of high clouds. Across Colorado and Wyoming temperatures will probably be above average by Sunday afternoon.

 

The milder air mass is from the Pacific and will be laden with moisture as it slams into California and Oregon this weekend. That moisture will have an impact across western Colorado late Sunday and Monday. Because of the mild and wet characteristics of the air mass the snow may be more dense than usual, and rain is likely in lower elevations of the West Slope. Be prepared for wintry travel at the high passes and some enhanced avalanche danger by Monday. The Front Range lower foothills and plains should stay dry through Monday.

 

Recap

This has been a season when snowstorms are characterized by narrow west-to-east bands aligned with the jet stream but only shallow upslope (wind from the east). Although that is not an uncommon occurrence, deep upslope associated with storm systems moving by to our south (4 corners lows) is a more familiar cause of big snowstorms. The result this season has been moderate intensity snow with sub-regions of that exceed expectations due to periods of intense snow associated with those bands. In the December 16-17 snowfall, the region of enhanced snow was right over Denver and DIA, and in the recent storm Boulder County got the big amounts.