Monthly Archives: November 2014

Monday cold wave update

NOON, Monday, November 10, 2014

As expected, temperatures really plummeted across northeastern Colorado and southeastern Wyoming this morning, and the cold front will push its way through southeastern Colorado this afternoon. The areas of snow have been sparse, but the snow is organized in east-west bands where there is local accumulation occurring. Through this evening the snowfall is likely to range from barely a dusting in many places to about 3 inches in some localized areas. Most of the Front Range corridor will probably get around an inch. Later tonight there may be areas of freezing drizzle and ice fog along the Front Range.

The coldest air is likely to be in place Tuesday evening through Thursday morning, with another round of light snow likely late Tuesday into Wednesday that can produce 1-3 inches in and along the Front Range. Nighttime temperatures should drop into the single digits, and the high temperature Wednesday will only reach the teens. It’s possible that the overcast will thin a bit Wednesday night. If it does, there may be a few valley areas on the plains that dip below zero.

The cold will remain but become a little less intense by the end of the week. Another cold front Saturday should prevent any big warm up and maybe bring a little more snow.

Very Cold with Light Snow by Monday evening

NOON MST, Sunday, November 9, 2014

Yes, the cold wave is still on the way Monday for the Front Range and eastern plains and is expected to last at least through the week. Several periods of snow and maybe a little freezing drizzle are expected throughout the week. The best chance for accumulation is Monday afternoon and evening, and again Tuesday night and Wednesday.

TIMING, THREE COLD FRONTS:

The arctic front will be making its way southward through eastern Wyoming in the predawn hours Monday, and then through eastern Colorado during the day. Cheyenne is likely to be in the cold air by daybreak. Colorado Front Range residents should not be fooled if it’s still mild in the early morning. The front will move through and temperatures will quickly tumble through the 30s and 20s and probably into the teens by evening. This is cold, dense, low-level arctic air, so Nederland might not get the front until several hours after Boulder. West Slope areas will have much less impact.

Another cold front Tuesday night will likely make Tuesday night through Thursday morning the coldest period with temperatures struggling to get into the teens Wednesday, and falling to the single digits Thursday morning. In fact, on Wednesday the high temperature in Denver and Boulder might be colder than the low in Fairbanks, Alaska where they are on the warm side of this weather pattern.

There is likely to be still another cold front in the series by next weekend, but the timing is less certain and temperatures might moderate a bit before it hits. But in any case, it is very likely that temperatures will remain below average through next weekend.

SNOW:

Snow, mainly light, is likely to develop within a few hours of the front, especially near the foothills. Snowfall through Monday evening should be enough to whiten the ground throughout eastern Colorado and Wyoming with about an inch. Some local areas may see 1-3 inches, especially near the foothills.

Another round of snow is likely to bring 1-3 inches more Tuesday night and Wednesday with the second surge of cold air. Although the timing is less certain, it appears that we may be dealing with another round of snow next weekend.

Cold wave begins Monday

1:00 PM MST, Saturday, Nov 8, 2014

Enjoy an unseasonably warm Sunday because a cold wave beginning Monday will bring temperatures that would be below average even if it were January. It will be felt very strongly for the Front Range mountains and eastern plains of Colorado and southeastern Wyoming, with lesser effects in western Colorado.

There is a chance the cold front won’t be through the Front Range area by Monday morning, but it is expected to be much colder by Monday evening with a good chance for light snow or snow grains developing by then. Beginning Monday night, low temperatures will likely drop to the teens or lower, and daytime temperatures will struggle to get into the 20s even in the lower elevations.

There is likely to be widespread 1-2 inches of snow throughout the Front Range and eastern plains beginning Monday afternoon or evening. There may be some localized areas in and along the Front Range that may see 2-4 inches, but a major snow event is not expected. Areas of freezing drizzle and ice fog may develop along the Front Range, especially during the nights and early mornings.

When will temperatures recover? There may be some moderation by the end of the week, but all indications right now are that another cold front next weekend can keep the below average temperatures in place. So the bottom line is that while some days may not be as cold as others, the 5-7 day period beginning Monday will feature below average temperatures and icy conditions at times.

Multi-day cold wave next week

12:30 PM MST, Fri, November 7, 2014.

You know how there is usually that one weather event every autumn that signals the arrival of the “winter” season? We’ll see that next week.

A long duration period of generally cloudy, unsettled weather and below average temperatures arrives Monday and is likely to persist all week for the Front Range, eastern Colorado, and southeastern Wyoming. It may not be here in full force Monday morning, but by Monday evening we are likely to enter a stretch where daytime temperatures remain near of below freezing even in the lower elevations, and nights may dip to the teens or lower. Western Colorado won’t see the change as dramatically.

I don’t expect a major snowfall with this cold snap, but widespread minor accumulations are probable across the Front Range and eastern plains beginning Monday. In fact, this is the type of setup that could result in areas of freezing drizzle and fog along the Front Range by Monday night or Tuesday.

So after a slight chance of minor precipitation tonight, enjoy the mild autumn weekend. It should be a good time to do that final autumn cleanup in the yard and make sure your house and car are ready.

For the weather weenies on the blog, this cold snap is the result of a weather pattern shift to a strong negative arctic oscillation. It was triggered at least in part by the remnants of the Pacific’s super typhoon Nuri that helped create an unusual surge of warmth into the arctic near Alaska. The anomalous poleward surge of warmth in the Pacific will be compensated by a southward surge of polar air in the eastern 2/3 of the United States.

Chance for snow is fading

NOON, Monday, Nov 3, 2014

The storm system moving through the area peaked early, and was not cold enough for snow in the lower elevations. But it did bring thunder and some hail to many areas in the early morning. These thunderstorms were quite unusual for the time of year and the time of day!

 

Although most of the storm’s energy has moved through, there is a little hanging back that is causing an area of light intermittent precipitation across northern Colorado (north of Longmont at NOON) and southeastern Wyoming.  There has been some moderate snow in Cheyenne, but it’s lighter in Larimer County, and mainly rain in the lower elevations. Webcams show Fort Collins is wet, not white.

 

The area of precipitation is progressing more eastward than southward, so it probably won’t reach Denver or Boulder. But I can’t yet rule out the small chance that the precipitation will shift southward into the Denver-Boulder-Longmont area. Even if it does, additional accumulation up around Nederland is likely to be minor, and inch of less, and if the lower elevations get any rain or snow, there should be little or no accumulation.

 

The rest of the workweek is looking dry, and probably getting pretty mild by Thursday.

Minor storm moving through late Sunday-Monday

It still appears that the storm system moving through Colorado Sunday and Monday will not be a major snow maker.

Some mountain snow and valley rain will become more likely in western Colorado on Sunday while it stays mainly dry along the Front Range and eastern plains, including southeastern Wyoming. Then, the likelihood for mountain snow and low elevation rain-changing-snow increases for the Front Range, eastern Colorado, and southeastern Wyoming Sunday night and Monday.

There is a good chance for several inches of snow in the mountains including Nederland, Brainard Lake, and Idaho Springs. In fact there  could be around 6 inches if the storm doesn’t move quite as fast as some numerical models are suggesting, but those higher amounts are more likely near and west of the continental divide.

For the lower foothills and adjacent plains along the Front Range, rain is likely to change to snow, but accumulation may be limited to mainly light accumulation on cars and grassy areas. If the changeover occurs before sunrise Monday (which it might, especially the northern Front Range), there is a better chance for accumulation. Snowfall during the day will be competing with high melting rates.

Don’t forget to turn your clocks back tonight!