10 AM MDT, Saturday, September 22, 2018
In the mountain time zone the autumnal equinox is this evening at 7:54 PM. So happy autumn!
The calendar might say autumn, but afternoon temperatures this weekend will continue to be more like summer. A change in the pattern will make the north-central United States much cooler next week. Although the Front Range won’t get cold, temperatures are expected to be more consistent with early autumn beginning Monday.
It would be nice to get some rain with the change to less warm weather. There is a small chance for rain early next week, but like the last cold front, the rain will probably be spotty and many areas will receive very little.
We are not yet being threatened by a cold air mass likely to bring widespread frosts to the northeastern plains. However, some of the valley locations that have a reputation for getting colder than everyone else (you probably know who you are) might see some frosty temperatures Tuesday or Wednesday morning.
6 AM MDT, Monday, September 17, 2018
Some clouds and cooler weather should move into the Front Range region as early as Wednesday, certainly by Thursday. But there is very little chance for rain at any one location.
For today and tomorrow the high temperatures are likely to be near record. For Denver the record highs Monday and Tuesday are 95 and 93, and in Boulder it is 93 both days. Boulder did already set a record of 93 on Saturday, eclipsing 92 from 1948. So summer is hanging in there for another few days, and nothing dramatically cold or wet is in the near future.
12:05 PM MDT, Tuesday, September 11, 2018
Several tropical cyclones are threatening U.S. states and territories, most prominent is Hurricane Florence for the Carolinas, and that will be dominating weather news through the weekend.
For the Front Range there is minor news possible in the form of record high temperatures today and tomorrow. There is enough moisture in the atmosphere to trigger cumulus clouds that will limit the solar heating. But even with that we are likely to get close to records. The records for today are 92 in Denver (1951) and 91 in Boulder (1974) and for tomorrow they are 94 in Denver (1911) and 93 in Boulder (1956). The warmth will still be with us on Thursday, but the records are pretty hot that day (96 in Denver and 95 in Boulder, both from 1990), so we will probably not set any records that day. It could be early next week before we see a real cold front and a chance for showers. Enjoy the late season heat. This is a far different atmosphere than what we had 5 years ago on September 11-12 when records rains triggered widespread floods and landslides.
6:30 AM MDT September 4, 2018
The moisture over the central Rockies this past weekend made a lot of clouds but it didn’t produce much rain for the northern half of Colorado. The chance for rain in the Front Range region is not over yet.
After a warm day today, a cold front will push through from the north this evening and bring cooler weather. At the same time an area of above average atmospheric moisture will be moving through the region today through Thursday associated with an upper level disturbance from the southwest. The result should be some showers and thunderstorms around this evening and then Wednesday and Thursday afternoons/evenings as well. In addition, there could be some areas of low clouds and drizzle or rain late tonight and into Wednesday morning.
2:15 PM MDT, Friday, August 31, 2018
The late summer weather pattern is expected to continue through the 3-day weekend. There are two difference between the last couple days and what you can expect this weekend. 1) High temperatures should be about 5-10 degrees cooler than yesterday and today. 2) The chance for afternoon and evening thunderstorms returns.
During the course of the weekend almost everyone in the Front Range region will probably experience a shower or thunderstorm at least once with amounts varying from a heavy downpour in a few spots, to very little in other places.
For the higher elevations some of the showers may have some graupel (snow pellets) or snow mix in, but this is not looking like the first real snowfall for the mountain region. September is the time where the first real snows hit the mountains, but we don’t see that just yet. For the lower elevations Mother Nature usually brings the first frosts and snow in early to mid October, but occasionally that could occur by late September. There is no indication of such an event in the near future, although a cold front is likely to at least turn it cooler late Tuesday or Wednesday.
Have a nice weekend!
7 AM MDT, Tuesday, August 21, 2018
An swath of anomalously high atmospheric moisture is moving through Colorado and Wyoming today and tonight. There are already sprinkles around this morning.
Sunny intervals will be limited today, and showers/thunderstorms will be around this afternoon and evening. The risk of thunderstorms may extend into the late night for parts of the Front Range. The chance for thunderstorms will continue Wednesday afternoon, but the risk is a bit smaller then.
Drier and warmer weather is due to make a return on Thursday and Friday, but I can’t rule out the return of haze from western fires.
12:50 PM MDT, Friday, August 17, 2018
A weak cool front from the west on Saturday will bring a small chance for thundershowers in the midday to afternoon hours and cool the temperatures just a little bit compared to today. Then another cool front from the north on Sunday should bring cooler weather by Sunday afternoon. The cool front on Sunday may bring a period of cloudy weather, but probably not much rain.
This season’s monsoon has not been very impressive. When it has streamed north into the southwestern U.S., it has been mainly south of Denver. The southern Front Range (including Colorado Springs) have had some wet weather, but the recent rain and hail was more of a severe weather setup than a monsoon pattern. Monsoon thunderstorms are typically slow-moving, wet, but non-severe (no big hail) and are connected with a plume of tropical moisture from Mexico. We haven’t had a strong pattern like that this month, and there won’t be this weekend.