Monthly Archives: April 2017

Snow is coming this evening

11:40 AM, Friday, April 28, 2017

The sunshine and low humidity should change rapidly from north to south this afternoon and evening, probably during the early afternoon in Cheyenne, the late afternoon and evening from Boulder County southward. Although it’s well above freezing in many areas now, the dry air should allow for strong evaporative cooling when the precipitation starts, so rain, if any, won’t last long.

 

Amounts

4-10 inches mountains, foothills, Palmer Divide area (locally  more than a foot in some mountain areas, especially south of I-70)

3-7 inches Colorado Springs

2-5 inches Boulder, Denver

1-3 inches Longmont, Fort Collins, Cheyenne

8-15 inches and windy for southeastern plains (along and south of I-70)

** mainly Friday evening through Saturday morning, longer in southeastern Colorado

 

What can boost amounts?

The storm is a rather classic setup for big Spring snows but the air over the Front Range Friday morning is remarkably dry. The storm will try its hardest to draw in moisture from the east starting this afternoon, but the really rich moisture may not be able to make it all the way to the Front Range before the storm system begins pulling east on Saturday.

 

That said, there is a small chance that the richer moisture will make it this far west and boost amounts along the Front Range, but that is probably about a 10% chance. For southeastern Colorado and the Front Range south of Colorado Springs the chance is greater for big snow.

 

Hard freezes

Milder weather should return after a widespread hard Freeze Sunday morning. But current indications are that we may have another period of frosts and freezes around midweek, so be patient with the tender annuals.

 

 

Snow late Friday

3:30PM, Thursday, April 27, 2017

A storm system late Friday through Saturday morning is likely to bring measurable snow to most of the Front Range region Friday night and Saturday morning.

 

Factors in favor of snow

The storm system, a 4-corners low, will be in a favorable position to cause widespread deep upslope flow throughout the eastern slopes of the Front Range. Temperatures should be cold enough for precipitation to be mostly or all snow.

 

Factors against really big snow

Despite the favorable conditions, atmospheric moisture is not likely to be very impressive by April-May standards. Although the storm may be very efficient at converting available moisture into precipitation, there could be a limit on how heavy it gets.

 

The result

Clouds and intervals of snow beginning Friday mid to late afternoon (possibly a bit a rain at first in the lower elevations) continuing through Saturday morning. Snow may begin by midday up toward Wyoming and in the Cheyenne area.

4-10 inches mountains, foothills, Palmer Divide

1-4 inches lower elevations

 

Sunday

After a widespread hard freeze, mild Spring weather should return.

Snow season might not be over yet

12:30 PM, Tuesday, April 25, 2017

The snow season of 2016-2017 has not measured up along the Front Range, with both Denver and Boulder running more than 35 inches below average (average is 57 inches in Denver and 93 inches in Boulder). Although we are not going to make up the difference this week, we may add a bit to the seasonal total by Saturday morning.

Tuesday night- Thursday

A  minor storm system tonight may bring some snow (or rain changing to snow) by Wednesday morning. There could even be a brief thundershower Tuesday evening. Some light accumulation should be expected in the mountains and Palmer Divide area, but little or nothing is expected in Colorado Springs-Denver-Boulder-Fort Collins-Cheyenne.

 

Wednesday and Thursday should be cool, but not cold, and mostly dry. Some intervals of clouds and precipitation should bring some more light amounts of snow to the mountains and maybe some rain showers to the lower elevations.

 

Friday-Saturday

Early indications are for a more organized storm system going into the weekend. I will update later this week, but at this point it does look like it should be cold enough for some snow in the lower elevations.

Last week of April: cooler, wet at times

1:05 PM, Sunday, April 23, 2017

Warm spring weather today and tomorrow (Monday) should give way to cooler weather beginning Tuesday and staying with us through the rest of April. There may even be some rain and snow, especially toward the weekend.

 

Tuesday is likely to be the first day with temperatures  near or a little below average and the chance for some precipitation. The chance is greater in the mountains, where it will be mainly snow, than it is in the lower elevations, where mostly rain is likely.

 

Don’t expect a rebound to 70-degree weather before the next storm system late in the week. April might end cold and wet (more on that later this week).

 

 

Cooler, some precipitation late Thursday and Friday

12:30 PM, Wednesday, April 19, 2017

After a long stretch of warm, dry weather some cooler unsettled weather is on the way for late Thursday and Friday. However, this is not shaping up to be a classic wet Spring storm. After a cool start on Saturday, warmer weather should be back in place by Sunday.

 

The first real chance for rain is late Thursday afternoon and evening as the upper atmosphere cools and convective showers and a few thunderstorms form. There is a good chance that most of the Front Range will see some rain, but amounts will probably range from very little in some places to local downpours in a few spots. Snowline is likely to be up near treeline.

 

Friday is likely to be cooler and mostly cloudy with another period or two of precipitation possible. The chance for snow may descend to the foothills, but accumulations are most likely in areas above 8000 feet.

 

 

Warm Saturday, Cool & Windy Sunday

12:20 PM, Friday, April 7, 2017

A Pacific cold front before daybreak on Sunday is likely to make daytime temperatures at least 15 degrees cooler than today and tomorrow. Areas of precipitation early Sunday are likely to be limited to mountain areas, especially west of the continental divide. Little or no precipitation is expected for the Front Range foothills and plains. But you may very well notice a gusty west or northwest wind with the cooler temperatures on Sunday.  Warmer weather should return by the middle of next week.

 

 

Maybe a little more this evening, then Spring returns

12:20 PM, Tuesday, April 4, 2017

There is some indication in the mesoscale models and the observations  that there may be one more short period of precipitation late this afternoon and evening before clearing out later tonight. So don’t be too surprised to see a bit more snow added before it’s all done.

 

After a cold start on Wednesday it should be a fairly mild day. Then warmer Spring weather is likely through at least Saturday.

 

 

Minor storm expected

6:30 AM, Monday, April 3, 2017

The storm system moving through southern Colorado tonight is somewhat limited in moisture and will go through its major intensification after it is east of our region. The result should be a relatively minor snowfall, from little or nothing in low elevations north and east of Denver to about 6-10″ in the mountains south of I-70. The timing should be late evening through early Tuesday, with some intermittent showery precipitation possible during the day on Tuesday. Hard freezes should be widespread at all elevations Wednesday morning followed by springlike weather for the remainder of the week.

6-10 inches: mountains and foothills south of I-70

3-7 inches: mountains and foothills north of I-70 and the Palmer Divide region

1-3 inches: along foothills from Boulder County south (Boulder, Broomfield, west & south sides of metro Denver, Colorado Springs

0-1 inch: DIA, Longmont, Fort Collins, Cheyenne

One storm fizzled and another is coming

12:15 PM, Sunday, April 2, 2017

A storm system heading our way will likely bring rain and snow to the region late Monday into Tuesday. Some guidance is suggesting somewhat heavy amounts in and along the foothills. It’s hard to get too excited given the storm predictions that did not verify Friday night. But the previous storm, although quite large, was weakening when it was in New Mexico at its closest approach to us. The next storm is a little different. It is likely to be in its intensification stage and may move through southern Colorado Monday night.

The potential exists for 6-10 inches in and immediate along the foothills, less further away from the foothills. That’s not a confident forecast at this point, and I will update tomorrow.

 

Snowless March

The official climate stations in both Boulder and Denver made it through March with no measurable snow. Only a trace (less than 0.1 inch) was recorded in both places. This had happened only twice before in Denver’s record (2012 and 1995). No measurable snow had happened four times previously in Boulder (2012, 1918, 1911, and 1910). I should note that the Boulder snowfall records a century ago were not of the best accuracy.