Colorado

Cold and Snowy President’s Day for Eastern Colorado

A slow-moving trough of low pressure is tracking across the Southwest U.S. this weekend, while arctic air has filtered into Eastern Colorado.  As a result, the Denver metro area and Front Range urban corridor are experiencing a cold President’s Day Monday with light snow impacting much of the region.

A cold front moved through on Sunday, with upslope winds developing behind the front as snow developed Sunday night.

Moisture has not been significant with this system.  Looking at the 700-millibar relative humidity analysis this morning (which corresponds to approximately 10,000 ft.), we can clearly see the low pressure system over the Southwest, but only modest moisture at the mid-levels of the atmosphere (image source: College of DuPage).

 

 

However, thanks to the cold air that arrived with this system, snow that fell last night was easily able to accumulate on roadways across the Front Range with impacts to this morning’s commute.

Overnight snow reports were quite variable, favoring areas west of I-25 along the Front Range, from Boulder south to the New Mexico border.  Denver snow totals were generally in the 1-2″ range overnight across most of the city, with lower amounts across the eastern metro area and higher amounts across the western metro area near the foothills.  

Areas from Western Lakewood to Golden received snowfall amounts of 3-5″ with some isolated amounts up to 6″, while farther north around the City of Boulder, snowfall generally ranged from 2-4″.

Across the Southern Front Range, Colorado Springs snow totals were in the 1-3″ range, while Pueblo and Canon City saw lighter totals in the 0.5-2″ range.

Last night’s snowfall was mostly a miss for the mountains along and west of the Continental Divide, except for the Southern San Juan Mountains where Wolf Creek Ski area picked up 10″ of snow.

The sun has come out late this morning across the Front Range, allowing for some recovery on the roadways per webcams despite temperatures in the low to mid teens (following morning lows in the single digits).

However, the region will remain under the influence of the upper level trough of low pressure with another disturbance expected to arrive tonight with light snow developing across the I-25 corridor overnight, which should once again result in a slick Tuesday morning commute.

Colorado Snow Pack Still Improving

Colorado’s snow pack continues to improve this season as a more active storm pattern has hit the high country during the start of 2019.  Colorado’s snow pack statewide has increased to 109% and will continue to increase as snow is poised to hit the high country starting today and lasting through tomorrow.  Snow totals expected for the high country over the next two days are anywhere between 2-4″ for most areas, while higher elevations and western facing slopes could see upwards of 6-8″.  Gusty winds associated with this disturbance will make for hazardous driving conditions for people making their way back from the high country today and tomorrow.  Expect slower than usual travel times, with dangerous conditions at higher elevations and mountain passes due to blowing snow causing white out conditions in some areas.  

Snow totals per NWS for the next two days are as follows:

Chances for snow over 1″ per NWS:

Storm system to bring widespread snow to Colorado over the next two days

A trough of low pressure will move across the Central Rockies this week, bringing snow to a large portion of Colorado over the next couple of days.  We’ve already seen several disturbances ahead of the main system impact the mountains of Colorado over the past few days, and will continue to see snow showers today.  The southwesterly flow has favored the San Juan Mountains the most, where ski areas have picked up over a foot of snow in recent days.

Looking at the most recent upper level wind pattern at 500-millibars, we can see the trough of low pressure centered over California this morning (image source: College of DuPage).

 

 

High Country Snow Outlook

This trough will transition eastward today, with snow showers west of the Continental Divide this afternoon becoming a more widespread snowfall overnight tonight through the first half of the day Wednesday.  The next image shows widespread moisture spreading into Western Colorado this evening (image source: Colorado Avalanche Information Center). 

Snow will fall heavily at times, with amounts of over one foot possible across the higher mountain passes and ski areas, especially across the central and southwest mountains south of I-70, as well as Steamboat in Northern Colorado.

Snowfall amounts for the mountain towns will likely range from 3-6″ for most areas from the Roaring Fork Valley to Vail and up to Steamboat, with amounts a little higher southward in places like Crested Butte and Telluride, and amounts a little lower in Summit County. 

The Wednesday morning commute will be impacted all across the high country, and strong winds will develop Wednesday morning and through the day as well, resulting in blowing and drifting snow.  Outside of the high country, even the lower elevations of the West Slope from Grand Junction to Montrose could pick up a couple of inches of snow Wednesday morning, with a slick commute expected.

Front Range Snow Outlook

As the trough moves across Colorado on Wednesday, an arctic cold front will approach from the north and push into Eastern Colorado Wednesday afternoon, resulting in a rapid drop in temperatures.  Upslope northeast winds will develop behind the front with snow developing across the Denver-Boulder-Ft. Collins areas Wednesday afternoon.  The image below is one model’s projected radar reflectivity at 5pm Wednesday, showing snow filling in across the urban corridor (image source: pivotalweather.com).

 

Snow will continue across the Front Range through the overnight hours Wednesday night before tapering off early Thursday morning.  Temperatures will plummet Wednesday afternoon through the overnight hours, allowing for snow to accumulate on all surfaces.  Low temperatures on Thursday morning are expected to approach zero across the metro area.

This will generally be a light/moderate snowfall event with favored upslope areas west of I-25 near the foothills picking up a few inches, perhaps more, with lesser amounts expected east of I-25.  Boulder tends to do better than most of the Front Range in this type of pattern, and could end up with some of the higher totals in the area.  There will be some potential for banded snowfall as well across the Front Range, in which case isolated higher totals would be possible if and where any heavier, slow-moving bands of snow set up.

The Thursday morning commute will be challenging across the Front Range, even if amounts end up on the lighter side given the cold temperatures in place.

Colorado High Country Snow

NWS has issued a Winter Weather Advisory for the Central/Northern Rockies above 8,000ft until 6:00PM February 3, 2019

NWS has issued a Winter Storm Warning for the San Juan region above 8,000ft until 6:00PM February 3, 2019

A strong system is making its way into western Colorado today bringing snow all along the Colorado High Country.  Most areas will see snow, with the San Juan range getting the most out of this system.  Areas to the north should see amounts between 3-6″ with 6-12″ possible at higher elevations.  Areas south should see anywhere from 4-8″ with higher elevations receiving over a foot of snow!  

These are great conditions for skiing as there will be fresh powder throughout the Colorado High Country today, but travel conditions could be hazardous at times especially on mountain passes where heavy snow and gusty winds could cause white out conditions at times.  Remember to have any necessary equipment, such as snow tires, chains, or all wheel drive when traveling in these types of conditions in Colorado’s High Country since failure to do so can result in being ticketed!

A look at total snow expected per NWS Forecast:

Colorado Snow Pack Improving!

Heavy mountain snow over the last month has really helped out Colorado’s snow pack, especially in the southwest area along the San Juan mountain range.  Previously SWE (Snow Water Equivalent), what is used to monitor Colorado’s drought, totals were around 70% for the San Juan mountain range indicating drought like conditions since there has been very little snow that has fallen early this season in and around that area.  Fortunately that has changed recently and the southwest region is close to 100% of average for snow pack from a multitude of strong storm systems that have dumped beneficial snow over the region.  This has raised Colorado to 109% statewide and is the first time Colorado has been over 100% total SWE this season! 

For reference, here is the snow pack from earlier this month with statewide SWE at 95%:

Current as of 1/25/2019 statewide SWE at 109%:

 

 

Fast moving storm to bring more snow to Colorado on Monday

A storm system will move across the Rockies today, bringing another shot of snow to the Colorado mountains during the daytime hours, with Eastern Colorado getting a round of snowfall tonight.  While this will not be as big of a snowfall producer for the high country as last Friday’s storm, we will see some quick bursts of heavier snow along with gusty winds as a cold front races across the state, which will impact road and travel conditions for the end of the holiday weekend. 

The Denver metro area (southern areas most favored) down to the Palmer Divide will also get in on the action tonight as the system moves east of the Continental Divide.

This morning’s infrared satellite image shows this low pressure system located over Utah and racing toward Colorado (image source: College of DuPage).

 

 

The short-range HRRR model projects snow to fill in across the western and central mountains of Colorado by around midday today (image source: weathermodels.com).

 

The heaviest snowfall across the high country is likely during the afternoon hours, though lighter snow showers will linger through the overnight period as well across northern and central Colorado.  Snowfall amounts of 6″ or greater will be possible across the higher elevations and mountain passes

Lesser amounts are expected across most of the mountain towns and valleys across ski country, but cold temperatures arriving with the cold front will allow snow to easily accumulate on pavement, and strong winds today and tonight will result in areas of blowing and drifting snow.

In general, the highest snowfall amounts are expected across the central and northern mountains.

Tonight, the system will swing into Eastern Colorado and a strong cold front will move across the plains and I-25 corridor, leading to a quick drop in temperatures with snow projected to fill in by late this evening, per the 12z run of the HRRR model (image source: weathermodels.com).

 

The exact track of the low pressure system is still in question, even this close to the event, which makes the Front Range snowfall forecast a bit more tricky.  Most of the models are projecting a minor snowfall event across the I-25 corridor, with northerly winds favoring southern Denver metro southward to the Palmer Divide.  On the other hand, the northerly winds will be much less favorable from downtown Denver north to Ft. Collins, as these areas will be experiencing a drier downsloping effect.

If the low pressure center were to track farther south than projected, then the potential for higher snowfall totals would exist.  But as it stands now, the Palmer Divide region will have the best chance of seeing meaningful snow amounts, as will the far northeast plains of Colorado where blizzard-like conditions will even be possible given the strong winds forecasted. 

Temperatures will quickly fall into the 20s tonight behind the cold front, so snow that does fall across the I-25 corridor will accumulate on road surfaces and could lead to a slick morning commute on Tuesday, especially in Douglas and Northern El Paso Counties, and into southern/central Denver metro as well.

Lingering snow should quickly taper off during the morning hours Tuesday before drying out Tuesday afternoon.  Temperatures will remain chilly on Tuesday, though, with continued breezy northerly winds.

Heavy snow tonight west of the Divide in Colorado

A Pacific storm system is moving into Western Colorado tonight with heavy snowfall amounts expected across much of the higher terrain of Colorado west of the Continental Divide.  This storm system has already produced several feet of snow across the Sierra Nevada in California, as well as heavy snow in Utah.  

Colorado’s mountains are now getting in on the action as well, with southwest flow favoring the San Juan and Elk Ranges south of I-70 initially.  The image below shows the most relative humidity analysis at the 7,000-millibar relative, which corresponds to roughly 10,000′ of elevation and is a good measure of moisture for the mountain areas of Colorado.

 

 

Later tonight, a gradual shift in the upper level flow from southwest to west, and eventually northwest, will allow the mountain areas along and north of I-70 to pick up heavy snowfall amounts as well.  By Friday morning, most of Colorado’s mountain areas west of the Continental Divide will have picked up impressive snowfall amounts, with double digit totals likely for many ski areas.  Road conditions will quickly deteriorate tonight through Friday morning throughout the Colorado’s high country, making for a challenging Friday morning commute.

East of the Continental Divide, this storm will mostly be a miss for the Front Range cities due to a lack of upslope flow.  However, a cold front will arrive Friday morning as the low pressure system swings across the Continental Divide, and banded snow showers are expected to develop across the I-25 corridor during the daytime hours.

Winds from the north/northwest will be unfavorable for Denver snow, with most areas east of the mountains expected to receive snowfall amounts of less than an inch, except perhaps under isolated heavier bands or across the Palmer Divide.  Temperatures near freezing as well as the timing during the daytime hours should also limit road impacts across the Denver area and I-25 corridor.

Looking farther out, the next system is slated to reach Colorado on Monday, and at this time there appears to be a chance for Denver to see a more meaningful snowfall event Monday night or Tuesday.