Monthly Archives: September 2018

Brief cool snap today; possible remnants of Rosa Tuesday

6 AM MDT, Friday, September 28, 2018

A cool air mass moved through the Front Range region overnight and will be with us all day. There will be some localized low clouds, and there is some drizzle out on the far northeastern plains, but most if not all of the Front Range region should stay dry.


After a chilly start Saturday we should see a nice warm-up. The cool air mass won’t be far away and may try to slip back in on us Sunday. So expect Saturday to be the warmer day of the weekend and take it as a pleasant surprise if Sunday is the same. Rain is not expected.


Rain from Hurricane Rosa

The remnants of the Pacific Ocean’s Hurricane Rosa is forecast to move into the Desert Southwest early next week bringing clouds and rain. The moisture should be moving through Colorado and Wyoming Tuesday/Wednesday. Right now it looks like the Front Range and eastern plains probably won’t get too much impact, but it’s worth watching. It does appear that there may be significant rain in some West Slope areas, especially the San Juan mountains.

Happy Equinox, More Autumn-like Next Week

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.

Turning a bit cooler midweek, but little chance for rain

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.

Hurricane madness elsewhere, but very warm and dry for the Front Range

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.



Cold front and area of moisture for Front Range region next few days

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.