Monthly Archives: November 2015

Snowfall is done, but blowing snow may occur is some locations

12:00 noon, Monday, November 30, 2015

As the big storm system pulls away to our northeast, we may see some areas with strong wind gusts out of the northwest tonight and early Tuesday (beginning a bit earlier in the Cheyenne region).  Not everyone will get the strong winds. The highest risk for blowing snow:

Exposed areas in the mountains (parts of Peak-to-Peak highway, I-80 in WY, and I-70 west of Denver),

Some places near the foothills (watch out on Hwy 93, and parts 470 west of Denver, I-25 near the Palmer Divide and the WY border, and U.S. 36 north of Broomfield).

 

The second half of the week should bring milder weather.

One more round of snow

12:00 noon, Sunday, November 29, 2015

The large, near-stationary storm system to our west that has kept us in clouds and occasional snow since Wednesday night is finally going to wobble through the Front range region tonight. Another round of snow is likely to accompany it late this afternoon or tonight. Amounts should be light, but falling on cold surfaces. Be prepared for winter travel conditions.

 

Expected accumulations: 1-3 inches most areas.

A few locations may get little or nothing (the chance for little or nothing is a little greater in Larimer County and up in Wyoming).

Likewise, a small portion of the area may get a little more than 3 inches from narrow southwest-northeast bands of snow this evening.

 

By the second half of this week we will probably be seeing temperatures climbing back above average for a couple days.

Winter weather spell not over yet

1:40 PM, Friday, November 27, 2015

Cold and unsettled weather is likely to continue into Monday, but not as intensely cold by Saturday afternoon. Also, there will probably be  intervals Saturday-Sunday when the overcast clears out a bit.

 

The snow isn’t completely over either. Although it is mainly insignificant flurries now, the parent storm that is spinning in place to the west of Colorado may spit out some disturbances that will enhance the snow for a few hours at a time.

 

The best chance for minor accumulations (about and inch) over the next 48 hours appear to be this evening into early Saturday morning, but not everyone will get that.

 

As the whole storm finally wobbles through late Sunday into early Monday, there will likely be more accumulating snow in the mountains and parts of the foothills and plains along the Front Range.  I’ll update either tomorrow or Sunday.

 

 

Thanksgiving winter weather update

3:45 PM, Wednesday, November 25th, 2015

As of mid afternoon low stratus clouds were thickening along the Front Range in response to the cold east-northeast flow.  Some areas of light freezing drizzle or snow grains may develop this evening, but amounts should be minor.

 

Later tonight though Friday evening should bring occasional snow (mostly light) and cold temperatures. Temperatures in the urban corridor probably won’t make it to 25 Thanksgiving Day and Friday and fall to the low teens and single digits at night.

 

Total snow Wednesday night through Friday evening:

Mountains and foothills (southeastern Wyoming to Pikes Peak region):   4-8″

 

Denver, Lakewood, Castle Rock, Broomfield, Boulder, Cheyenne:  3-6″

 

DIA, Colorado Springs, Longmont, Fort Collins: 1-4″

 

But when might it snow the hardest?

Good question, but a little tough to answer since the main storm system won’t actually move through. But this is what I think is the most likely evolution:

Phase 1, Wed night & Thanksgiving morning: minor accumulation (mostly 0-1 inch, with up to 2 inches in some spots near foothills).

 

Phase 2, Thanksgiving afternoon and evening: this will probably be the snowiest period. Expect winter driving conditions.

 

Phase 3: Friday: intermittent snow, minor accumulation.

 

Phase 4: although Saturday and Sunday will likely be less cold and a little less cloudy, there is some question about whether there will be more accumulating snow. I’ll update Friday.

Multi-day winter weather stretch begins Wednesday

1:30 PM, Tuesday, November 24, 2015

A cold front Wednesday morning will initiate a cold period that lasts through the weekend. Thanksgiving Day and Friday are likely to be the coldest days, with occasional light snow and maybe freezing drizzle.

 

Timing:

The cold front should move south from Cheyenne to Colorado Springs Wednesday morning (don’t be fooled if it’s still mild early). Low clouds are likely to develop north-to-south late in the day, with some light snow or freezing drizzle possible by Wednesday evening. Occasional snow is then likely Thanksgiving Day and into Friday with temperatures only reaching the 20s during the day.

 

Amounts over 2 days beginning Wednesday evening:

In and near the foothills and Palmer Divide (west & south side of metro Denver, Castle Rock, Broomfield, Boulder, Cheyenne): 3-6 inches. Maybe a thin coating of freezing drizzle Wednesday night-Thursday morning.

 

Eastern plains (east side of metro Denver, Longmont, Fort Collins): 1-3 inches.

 

Colorado Springs area: 2-4 inches (they may get most of theirs on Friday, while Denver-Boulder will probably see more on Thursday than Friday).

 

Front Range mountains: 3-6 inches, the foothills may get more than the higher mountains, and the overcast may thin at times in the higher elevations.

 

Saturday-Sunday: although the overcast may thin out a bit and the temperatures may become less cold, a mild sunny weekend is not expected. As the remnants of the western storm finally moves east, there may be another period of snow, but it’s too early to tell right now.

 

 

 

Wintry Thanksgiving

12:15 PM, Monday, November 23, 2015

A cold front on Wednesday is expected to usher in a multi-day cold spell for the Front Range and eastern plains. Low clouds and some light snow or freezing drizzle are likely for Thanksgiving, but a big snowstorm is unlikely.

 

A large storm system over the West by midweek is likely to spin in place and slowly weaken without ever moving into Colorado. In addition, a large & cold high pressure system is likely to slide down the Front Range  from the north on Wednesday and keep it cold through the holiday weekend, especially Thanksgiving Day and Friday when temperatures are likely to stay in the 20s for the Front Range urban corridor.

 

The cold air will be relatively shallow, so the result is likely to be low clouds and some periods of light snow or, in the lower foothills and plains, some freezing drizzle and ice fog. Nederland stands a better chance of seeing some breaks in the overcast than the lower elevations.

 

So the bottom line is: no major storm is expected at this time, but you should plan for some wintry weather on Thanksgiving, possibly beginning late Wednesday.

A few spots may get brief snow flurries or squalls

12:55 PM, Friday, November 20, 2015

A sharp cold front cruised through Boulder and DIA just before noon, and should be through Colorado Springs by 2 PM. Some narrow bands of snow oriented northwest-to-southeast have developed mainly north of Fort Collins through 1PM. A few local spots around Cheyenne experienced brief heavy snow in those bands.

 

The narrow bands of snow will continue to re-develop and dissipate as the whole areas sags south this afternoon and evening. For the lower foothills through eastern plains, some areas will get little or nothing, while other areas will get a brief period of light accumulating snow. A subset of the area (probably less than 20% of the Front Range region) may receive a brief burst of snow that results in an inch or two.

 

Accumulations (by midnight):

Denver-Boulder-Fort Collins and lower foothills: 0-1/2 inch, with a smaller portion of the area receiving 1/2-2 inches.

 

Colorado Springs: most likely a dusting or zero, with just a small chance of an inch.

 

Nederland, Eisenhower Tunnel approach: an additional 1-3 inches, maybe more up at the high passes.

 

Thanksgiving outlook: After a cold start on Saturday, Sunday -Tuesday should be dry and milder. A large storm moving southeastward through the northwestern U.S. will likely impact travel in mountain areas Tue-Wed to the west of CO and WY. That storm stands a good chance of bringing snow and cold to the Front Range region on Thanksgiving Day, but at this point it’s uncertain if it will be minor or something more significant.

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.