2:30 PM, Friday, October 21, 2016
The good news is that we are in for another nice weekend with mainly sunny skies and warm temperatures throughout Colorado. In the Denver-Boulder area the average high temperature this time of year is in the low 60s, and we will likely run nearly 15 degrees higher.
The not-so-good news is that we really need rain or snow, and there are no major storms on the horizon for the next week. There will likely be a cold front at midweek, but that will probably bring only a small, temporary cooling and little or no precipitation. Most locations in the Front Range region have been remarkably dry from July through now (although the Colorado Springs area had a wetter mid-summer than most). The Boulder climate station has received less than 40% of average precipitation since July 1st. So fire danger remains with us for at least the near future.
12:45 PM, Monday, October 17, 2016
A cold front on Tuesday evening is likely to bring a cool day on Wednesday, just like last week. Unlike last week, Wednesday is not likely to be overcast all day and there is even less chance for rain this week. The cool down should be short. After a cold start on Thursday morning, temperatures are likely to be above average again by the end of the week. Since precipitation is likely to be light, if it occurs at all in the foothills and plains, we will still be dealing with elevated wildfire risk when warm weather returns at the end of the week. In the higher mountains there is a better chance for light snow accumulation, but nothing very big.
Today’s warm dry wind in and along the foothills should relax a little bit by Tuesday, but the cold front Tuesday evening may bring a renewed period of gusty northwest winds for a few hours.
1:30 PM, Tuesday, October 11, 2016
A cold front this evening is likely to make Wednesday at least 20 degrees cooler than today. The front is already through Casper, WY at 1PM and will likely move through Cheyenne late this afternoon and down the Front Range this evening. But it won’t last long. After a frosty start on Thursday, warming weather should return for late in the week.
We are not likely to get any precipitation of significance with this cold front. But, the surge of cooler air does stand a good chance of triggering some low clouds Wednesday morning, and maybe a few areas of drizzle.
11:55 AM, Wednesday, October 5, 2016
Another cold front will move in from the north tonight and cool the Front Range region a bit more. So far incidents of frost and freezes have been isolated to the cold spots of the Front Range and eastern plains. A lack of clear skies and calm winds in many areas will probably prevent widespread frosts and freezes on Thursday morning. But on Friday morning the chances are better for frosts and freezes across many parts of eastern Colorado, including the Front Range region.
Tonight’s cold front is not very strong or moist, but it will probably be enough to trigger areas of clouds and showery precipitation in the Front Range region on Thursday. Because long-duration, steady precipitation is not expected, it should not get cold enough for snow in the lower foothills or plains. There may be a dusting in the higher foothills and mountains.
It appears that a nice mid-autumn weekend is shaping up. Assuming we don’t get much rain or snow Thursday, elevated fire danger may still be with us through the weekend. In Boulder the July-August-September total rainfall was a mere 2.12″, the driest for that period since the current climate station was established in 1990, and likely the driest July-August-September in at least 67 years.
12:45 PM, Monday, October 3, 2016
Cold fronts Monday night and Wednesday night will send the temperatures to autumn levels for a change. We are not expecting significant widespread precipitation to quench the extreme dryness of the Front Range, but some spotty precip is probable Wednesday night or Thursday.
The first front is bringing a few areas of showers to the mountains right now, but the amounts are not that great, and little or no precipitation is expected along the Front Range and northeastern plains.
The second cold front Wednesday night maybe associated with more north-northeast winds, so clouds and some areas of mainly light precipitation are more likely. Mountain areas will probably see some light snow accumulation. For the Front Range urban corridor the air mass could get cold enough to mix in some snow, but only if it rains long enough to help cool the lower atmosphere, and it’s not the middle of the day. Since the confidence regarding the precipitation is still low, let’s say the first small possibility of snow is Thursday, but it’s not likely.
By Friday morning there may be widespread frost in the lower elevations of the Front Range and northeastern Colorado. That would be pretty close to the climatological average if it happens.
7:25 AM, Friday, September 30, 2016
At 7AM there were some showers moving eastward across the Front Range region and are likely to make a few places wet during the morning. Although drier air and some sun is likely to move in behind the showers, the level of atmospheric moisture today suggests that more showers or a thundershower are likely to redevelop later this afternoon or evening.
Saturday through Monday are looking mainly dry and warmer than average across Colorado and Wyoming. Although there may still be enough moisture around Saturday to trigger an isolated shower, it should overall be a nice weekend for outdoor activity.
The next cold front is due to sweep across the area around Tuesday bringing cooler weather and some rain and snow along and west of the continental divide. It doesn’t look like it will produce much if any precipitation for the Front Range urban corridor, but we can’t completely rule it out yet.
The autumn equinox is tomorrow (Thursday) at 8:21 AM MDT. Expect this coming weekend to be much cooler than last weekend, with a scattering of showers possible in the mountains.
A Pacific cold front should be moving east through western Colorado early Friday, and probably through the Front Range region late Friday. A brief burst of rain and squally winds may accompany the cold front, but a widespread significant rain is not expected. Above treeline a light accumulation of snow may whiten some mountaintops.
Saturday and Sunday are likely to be mainly dry, but because of cold air in the upper atmosphere I can’t rule out a brief shower in the afternoon, especially in high elevations where it could be snow or graupel. And for those who don’t know, graupel is small snow pellets that form in convective clouds, fairly common in the mountains in summer and early autumn.