Monthly Archives: February 2015

Next chance for snow late Sat/Sun, then more Tue

12:20 PM, Friday, February 27, 2015

A large storm system over the western United States will bring heavy snows to the mountains of Colorado late Saturday through Sunday night.  Well over 2 feet is likely in some areas, especially west-facing slopes south of I-70.

For the Front Range this weekend, some intermittent light snow is likely in and along the foothills Saturday through Sunday, mainly late Saturday into Sunday. Accumulations are likely to be light for most areas (a dusting to 3 inches). However, there may be some narrow bands oriented southwest to northeast that produce a few hours of heavier snow for a subset of the area. I’d put that at about a 20% chance for any specific part of the Denver to Cheyenne corridor, and less chance in Colorado Springs.

Monday-Tuesday:

Unsettled weather continues into next week, but it looks like Monday will probably be a bit warmer along the Front Range with temperatures possibly climbing above 40 degrees along the foothills. Another strong cold front on Tuesday has the potential to bring another significant snowfall to the Front Range region.

Warmer:

It appears we may be in for a warm up late next week, but that’s still pretty far off for me to have high confidence.

Records:

Denver set a new February snowfall record of 22.2 inches. It’s possible they will add a little to that Saturday night. Pueblo is only 1.4 inches from  from its February snowfall record of 20.1, and it was still snowing lightly this morning but I don’t think they reached it. Boulder is up to an impressive 54.6 inches. The climate day in Boulder ends at 5PM, so there isn’t much time to add more to this total tomorrow, but we might.

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More snow today, probably a lull Friday

8:50 AM, Thursday, February 26, 2015

It was another storm of noteworthy variation, with snow exceeding expectations near the foothills of Boulder and Jefferson County where over a foot occurred in some places (12.1 so far in Boulder). Very little fell in Fort Collins and Colorado Springs on the downwind side a prominent east-west ridges. Today and tonight should have periods of snow as well as periods when the sun briefly shines through thinning in the overcast.  It appears that there may be an enhanced period with accumulating snow in the late afternoon or evening. Additional accumulation is likely to vary from a dusting to as much as 4 inches.

If we get a lull in activity it will most likely be Friday into early Saturday.  A storm this weekend should produce plentiful snow in many of the mountains areas, especially the San Juans, Elks, and Sangre de Cristos. Some of the snow (at least a few inches) will probably reach the east slopes of the Front Range late Saturday and/or Sunday. And it’s not over then either. Additional periods of snow are likely along the Front Range through Wednesday. I’ll give more details in the coming days.

I don’t think Denver got the 4.9 inches it needed for a new February record, but I have not seen the DIA report yet. Boulder is up to 50.5 inches of snow for the month. Only two months in the Boulder record had more (56.7 March 1970, 52.5 Dec 1913).  But accurate snowfall records only began in Boulder in 1990. Poor siting and old measuring techniques likely cause the older records to be at least 20% lower than equivalent storms today. So the 56.7″ in March 1970 would probably be close to 70″ if it were measured today.  Still, we have accumulated an impressive total for February so far, well ahead of any previous February and particularly noteworthy since January and February are typically the drier winter months. And, February has 2-3 fewer days than the other months!

Snowy commute Wednesday evening

5:00 AM, Wednesday, February 25, 2015

The next cold front should push through Cheyenne about midday, and then through Boulder and Denver in the early to mid afternoon. Snow is expected to develop before the evening commute. The bulk of the accumulation for the Boulder-Denver area should be the late afternoon through the evening, but light intermittent snow is likely through Thursday.

Accumulations are likely to range 3-7 inches in the lower elevations, with the lower end of that range more likely north of Boulder, and the higher end near the foothills from Boulder south through the west side of Denver. 6-10 inches is expected in the mountains and foothills of the Front Range.

Town-specific:

Nederland, Brainard Lake, Evergreen, 6-10 inches

Boulder, Broomfield, Castle Rock, west & south sides of Denver, 4-7 inches

DIA, east side of Denver, Longmont, Fort Collins, 3-5 inches, possibly less in Weld County

Friday through Wednesday:

Cold unsettled weather continues. Significant snow is expected this weekend in the western Colorado mountain areas, and possibly extending to parts of the Front Range late Saturday.

February snowfall record:

Denver sits only 4.9 inches below its February snowfall record of 22.1 inches. But since DIA is not the snowiest side of town there is only a small chance of reaching that tonight. But there could be more snow before the month is over on Saturday

Boulder is at 38.4 inches for the month, well over the old record of 32.1. Boulder is also at a record 2.71 inches of moisture. The snowiest of any month, 56.7 inches in March 1970, appears out of reach.

More snow arrives Wednesday

5:00 AM, Tuesday, February 24, 2015

The next period of snow for the Front Range is likely to arrive Wednesday afternoon. It does not look as big as the last storm, but roughly 3-6 inches appears likely for the Front Range corridor from Colorado Springs to Cheyenne, maybe a little less east and northeast of Longmont, and a little more in the higher elevations south and west of Denver.

Timing:

The snow is likely to start by afternoon Wednesday in the northern Front Range and the Cheyenne area, and spread into the Denver-Boulder area by the evening commute. Most of the accumulation with this round is likely in the late afternoon and evening, so be prepared for a wintry commute Wednesday in Denver, Boulder, and Fort Collins. On Thursday only areas of light snow are expected with minor additional accumulations.

Beyond Thursday:

The very mild weather we enjoyed much of this winter is gone for at least the next week. Continued cold and unsettled weather will continue into early next week. The next chance for significant snow is late Saturday, especially for western Colorado.

Snow winding down, but not over yet

12:45 PM, Sunday, February 22, 2015

The widespread moderate and heavy snow is mainly over the mountains and foothills of central and southern Colorado now. But as the storm to our southwest churns, areas of snow are likely to continue moving north through the Front Range region this afternoon and tonight. At times the snow will stop and the sun might shine dimly through the clouds, and at other times snow may re-intensify for a couple hours. Additional accumulations Sunday afternoon through Monday morning for the Front Range corridor from Denver to the Wyoming border should range from Trace-4 inches. It may be a little heavier down toward Colorado Springs and the foothills southwest of Denver.

Although temperatures are likely to climb above freezing Tue and Wed, it may not get back to average (mid to upper 40s for Denver-Boulder). So there will likely be snow on the ground when the next snowfall hits Wednesday evening. At this point that storm doesn’t look as heavy. But it look possible that we may enter another multi-day cold spell with more than one period of snow through the weekend.

And yes, the Boulder coop climate station reached a monthly total of 34.6 inches of snow as of 7AM, a new February record. We may be on track for a month that exceeds 40 inches. That has happened in every month from October to April except for January and February, historically the drier mid-winter months.

Snowy/colder Saturday afternoon & night, light snow Sunday

12:15 PM, Saturday, February 21, 2015

As expected, most of the Fort Collins to Denver corridor received minor accumulations (Trace-3 inches) through 7AM.  There were some local exceptions, most notably the Broomfield-Westminster area where 5-10 inches fell.

A strong cold front just crossed the Cheyenne area at noon and should move down the Front Range this afternoon. Temperatures will fall and snow will likely become more steady and perhaps reach moderate or heavy intensity at times late this afternoon or evening. The snow is probably going to decrease in intensity Sunday morning and become more intermittent. The exception is the Front Range south or Pueblo and the mountains south of I-70 where moderate or heavy snow may continue at times into Monday morning.

FOR THE CHEYENNE-BOULDER-DENVER-COLORADO SPRINGS CORRIDOR:

Turning colder with snow becoming more steady and roads getting icy during the afternoon and into the evening. Snow intensity decreasing Sunday morning, probably before daybreak north of I-70. Some intermittent snow is likely, especially near the foothills Sunday afternoon and night. Temperatures will likely fall to with a few degrees of 10 tonight, stay around or just below 20 Sunday, and fall to between 0 and 10 Monday morning.

Most likely additional accumulations Saturday afternoon through Sunday morning:

4-8 inches Cheyenne, Fort Collins, Longmont, DIA.

6-10 inches Boulder, Broomfield, Denver & its west and south suburbs, Colorado Springs.

8-16 inches foothills, mountains, Palmer Divide, heaviest most likely south of I-70.

Most likely accumulations Sunday afternoon through Monday morning:

an inch or less in Larimer and Weld counties, and the Cheyenne are,

1-3 inches in the Boulder-Denver-Colorado Springs area.There is a small chance that more substantial snow will re-develop late Sunday (greater than 3 inches), but it’s probably only a 20% chance, even less north of Boulder County.

NEXT ROUND

We probably won’t have a chance to melt out this snow before the next cold front and snowfall arrives late Wednesday or early Thursday.

BOULDER FEBRUARY RECORD:

As of 7AM the February snowfall total in Boulder is at 24.2 inches. Another 8.0 inches would establish a new February record. Between this weekend and the next snow likely Wednesday night, that seems very reachable.

Fairly minor snow Friday night, becomes more serious Saturday afternoon or night

12:00 noon, Friday, February 20, 2015

Over the last few days we have been watching the development of a significant winter storm for Wyoming and Colorado. The biggest change over the last few days is a slight shift of the storm’s main focus to the south and west, and a later arrival of the most intense part.

GENERAL FORECAST FOR COLORADO/SOUTHERN WYOMING

Intermittent precipitation is likely this evening into Saturday morning (possibly starting as rain in the lower elevations). It will be mainly north of I-70 in the mountains, and north of Colorado Springs along the Front Range. It is likely to be a nuisance type, with 0-3 inches of snow, except in the north-central mountains of Colorado and the Laramie Range of Wyoming where roads may get rough in some heavier snow.

From late morning through afternoon Saturday a strong cold front should move from Wyoming and down the Front Range of Colorado and initiate a more serious period of snow Saturday afternoon through midday Sunday. The potential for heavy snow south of Colorado Springs and in the mountains south of I-70 is likely to last well into Monday. An additional 6-12 inches is likely in the lower elevations during this period (except less than 6 in the northeastern Colorado plains east of Greeley and Longmont). 10-20 inches is likely in the mountains with some of the central and southern Colorado mountains perhaps exceeding 20 inches in some locations.

SPECIFICS FOR COLO SPRINGS-DENVER-BOULDER-FORT COLLINS

In a nutshell… relatively minor impacts tonight through Saturday morning, more serious snow with winter road conditions Saturday afternoon/evening through midday Sunday, probably minor impacts Sunday afternoon through Monday but with more uncertainty during this last period regarding another round of heavy snow.

Most likely accumulations:

This evening through Saturday morning 0-3 inches.

Saturday afternoon/evening through midday Sunday, an additional 6-10 inches lower elevations with the most south of a line from Lyons to DIA, 10-16 inches in the mountains.

Sunday afternoon through Monday; this period is the most uncertain depending on the location of the storm to our southwest. 0-2 inches in Larimer and Weld counties, 1-4 inches in the Denver-Boulder area, 3-6 inches in the south Denver suburbs and south. These accumulations do not include a small chance that a period of heavier snow may occur in the Denver-Boulder area late Sunday or early Monday.

3-day totals: 6-10 inches Cheyenne-Fort Collins-Longmont; 8-14 inches Boulder-Denver-Colorado Springs. 10-20 in mountains and Palmer Divide with the heaviest mountain totals are a little more likely south of I-70.

NEXT WEEK?

It appears that we won’t warm up too much this time before the next surge of cold air and snow, probably late Wednesday or Thursday.