Monthly Archives: March 2016

Update: perhaps a small shift toward foothills in heavy snow potential

8:45PM, Tuesday, March 22, 2016

The winter storm late tonight and Wednesday is still poised to produce quite a gradient in snow across the Front Range urban corridor. One change from the midday update is that it appears the storm may begin to intensify rapidly late tonight before it moves into eastern Colorado. That would allow a period of northeasterly upslope flow in the early morning hours and the potential for a brief period of heavy snow (or rain changing to snow) along the foothills before the storm really organizes to the east. There may even be a rumble of thunder. Be prepared for wintry travel tomorrow morning. And if there is little or no snow where you are, check on the conditions where you are going. Accumulation may be highly variable due to localized convective snow.

 

Most likely accumulation range (and the %chance for at least 10 inches):

Denver, Lakewood, Littleton: 4-8 inches  (20% chance of at least 10)

Castle Rock, Aurora, DIA: 5-10 inches (30% chance of at least 10)

Westminster, Boulder, Longmont, Fort Collins: 1-5 inches (10% chance of at least 10)

Cheyenne: 4-7 inches  (30 % chance of at least 10)

Colorado Springs: 0-3 inches (almost 0% chance of 10)

Northeastern plains: 6-14 inches (with at least a 50% chance of more than 10)

 

 

Big difference in snow potential across metro Denver

12:50 PM, Tuesday, March 22, 2016

The first of three potential Front Range snowfalls between now and the end of March will occur tonight and Wednesday. This storm, although strong, will not be characterized by deep upslope flow, so areas near the foothills have the smallest potential for heavy snow, while the northeastern plains (and possibly the east side of Denver) are likely to see some heavy snow and blowing snow.

 

The storm will first impact the mountains tonight, mainly west of Peak-to-Peak highway. As the storm system intensifies Wednesday morning in east-central Colorado, the northeastern plains are likely to see some areas with heavy snow and blowing snow, perhaps after some rain initially. Along the Front Range, north winds will not favor sustained snowfall, except to the south of Denver as the north winds push up the Palmer Divide. In some areas of light precipitation it may stay warm enough so that rain occurs.

 

Mountain & Palmer Divide accumulation: 4-8 inches, less in the foothills (below 8000′) of Boulder and Larimer counties.

 

Lower elevations:

3-6 inches: along and south of a Lakewood-Denver-DIA line, but not Colorado Springs.

6-12 inches with high wind: parts of the northeastern plains (~25% chance this will be as far west as Aurora and DIA.

0-3 inches: northwest suburbs of Denver, Boulder, Longmont, Fort Collins; and to the south of the Palmer Divide in Colorado Springs (yes, there may be areas with no snow).

 

The next 7-10 days: another storm Friday night and Saturday looks like it will be more of the classic “upslope” type bringing widespread snow, but it’s too early to pin down amounts. Mid to late next week may bring another snowy period to close out the month.

 

Snowy this afternoon (Thursday) into Friday

11:55 AM, Thursday, March 17, 2017

The initial snow kicked in a bit earlier than expected (mainly in Larimer, Weld, and Boulder counties) and is melting on the warm road surfaces as of noon. Expect conditions to get more wintry by this evening and into Friday morning.

 

An area of mainly light snow is expected to become more organized from north to south this afternoon and evening and continue into Friday.  Within the area of light snow we will likely get narrow east-west bands of heavy snow. Most places from Denver to the Wyoming border will probably get at least a brief period of heavier snow sometime late today through early Friday, and a small subset of the area (10-20% of the area) may get a multi-hour period of heavy snow. The chance for the heavy snow is lower south of Denver and north of Cheyenne.

 

Timing:

This afternoon: Intermittent snow is likely from Denver northward. The chance for heavier bands of snow will slowly increase, especially north of I-70.

This evening through Friday morning: Light snow, with some localized heavy snow periods.

Friday afternoon: snow becoming more intermittent and dissipating.

 

Amounts:

Metro Denver, Boulder, Longmont, Fort Collins, Cheyenne: most likely 3-6 inches, but a subset of the area will probably see 6-10 inches.

Nederland, Brainard, Estes: 4-10 inches

Colorado Springs: 1-3 inches

 

Impacts:

Road conditions may change sharply over just a few miles due to the variable nature of snow intensity this afternoon through Friday morning.

Slushy and icy roads likely Friday morning, possibly in some areas by late this afternoon.

 

Weekend Outlook:

Dry and mainly sunny. After a cold start on Saturday, it should warm up. The next chance for cold, unsettled weather is Tuesday or Wednesday next week.

 

Cold & snowy end to the week

1:05 PM, Wednesday, March 16, 2016

A round of colder, cloudier, and occasionally snowy weather is likely Thursday evening into Friday for the Front Range region. Although a big snowstorm is not expected, there may be enough to impact travel.

 

First the challenge, since that’s important in this case. This had been looking like a minor storm, and it very well may be. But today’s developments indicate that there is a little better chance for a period of heavier snowfall rates Thursday night or early Friday, mainly from Denver northward.

 

Timing:

Thursday. Some spotty precipitation possible by late afternoon, possibly rain at first in lower elevations. Periods of snow (mainly light, but maybe some brief heavier periods) will probably hold off until after dark.

Friday. Periods of snow, mainly light but maybe some heavier periods. Probably dissipating late in the day.

Saturday. After a cold start, spring will make a comeback with pleasant temperatures by Sunday. Spring begins at 10:30 pm MDT Saturday.

 

Accumulation:

Most likely:

2-4 inches Denver, Boulder, Fort Collins, Cheyenne

4-6 in Nederland

0-2 inches in Colorado Springs.

Possible (only about 20% chance): 4-7 inches in some northwest-to-southeast bands in the Denver to Cheyenne corridor

 

 

Last week of winter may bring some winter weather

4:25 PM MDT, Sunday, March 13, 2016

The Spring equinox is next Saturday evening (March 19th) in the mountain time zone, although it has been quite springlike already. We are in for a colder and more unsettled week beginning Monday in the mountains, and Monday night on the eastern plains.

 

Accumulating snow will probably be limited to the mountains (mainly west of Peak-to-Peak highway). There may be a brief shower (rain or snow) in the lower elevations of the Front range late Monday or Monday night, but little or no accumulation is expected. Although temperatures will be colder, it should still be close to average Tuesday-Wednesday (daytime mostly in the 40s in the lower elevations).

 

On Thursday another cold front and storm may bring snow late Thursday and/or early Friday. It’s too early for details, but the Thursday night storm looks like the next real chance for some accumulating snow in the Front Range urban corridor.

Mild weekend, colder Tusday

12:25 PM, Friday, March 11, 2016

Above average temperatures and mainly dry conditions are likely into Monday. Although a few showers or thundershowers may be around late Saturday, many locations are likely to stay dry.

 

A shift to colder and more unsettled weather is likely Monday evening, but at this point it doesn’t look like a major storm is brewing. Another cold front late in the week may bring another chance for precipitation, but that’s still too far off to go into detail yet.

 

Remember that daylight saving time starts Sunday!

Scattered light precip, a few pockets of heavier rain/snow

3:30 PM, Sunday, March 6, 2016

A few days of cooler (but not cold) weather is in store to start the week, along with some precipitation in places Sunday evening and Monday.  There are a few areas of rain and snow around Sunday afternoon, but it’s mainly dry east of the continental divide.

 

On Monday a storm system will be moving east through Colorado and Wyoming. Organized easterly upslope flow is not expected, so areas east of the continental divide should have mainly scattered areas of precipitation. Almost all areas will probably see some rain showers (snow in foothills and mountains), with light amounts overall. However, a small subset of the area may experience brief heavier precipitation, possibly with thunder. There will be greater cooling in the heavier precipitation which could change the rain to wet snow even in the lower elevations. Let me emphasize that the heavier areas of rain/snow are likely to be localized, and many areas won’t see that. The chance for heavier showers appears to be a little greater north of the Denver-Boulder area.