Generally dry and very warm through the weekend

1:30 PM MDT, Friday August 16, 2019

The atmosphere over Colorado should continue to be dry with little or no monsoon influence through Monday. The only exception is that a surge of slightly moister and less hot air moved into eastern Colorado from the Great Plains this morning. That should enhance the chances of thunderstorms a little, mainly east of I-25. The chance for thunderstorms Saturday and Sunday will be very small, and afternoon temperatures in the low elevations are likely to climb to the 90s. Vegetation has become dry so be especially careful with fire.


There is indication that a surge of monsoon moisture from the Pacific Coast of Mexico might arrive in the middle of next week. It’s not looking like a very impressive surge of moisture, but it may be enough to increase the chances for widespread showers.

Late day thunderstorms this weekend, dry next week

3:20 PM MDT, Friday, August 9, 2019

For those who like to get some high country hikes in this time of year, you may be familiar with the tendency for afternoon lightning associated with monsoon-pattern thunderstorms. Those will be around this Saturday and Sunday for both the mountains and plains. So keep an eye to the sky. But for several days now the indications have been for a dry period  with the monsoon moisture pushed to the south of Colorado beginning on Monday and possibly lasting all week. That would mean warm conditions with lower than average chances for late day thunderstorms.

Cooler, some locally heavy thunderstorms today

6:15 AM, Thursday, August 1, 2019

An area of high atmospheric moisture is moving across Colorado today. This will increase the amount of afternoon clouds and thunderstorms and keep the afternoon temperatures cooler than what we have seen lately. A few areas in the Front Range and eastern plains regions will probably see some heavy rain in the thunderstorms, so it is good to keep an eye out for localized flash flooding this afternoon and tonight.


The high moisture content of the atmosphere will decrease as we go into the weekend, so although the chance for thunderstorms will remain, the coverage of thunderstorms should decrease after today.

The Southwest monsoon

Moisture in the mid and upper levels today is connected with the tropical Pacific off the West Coast of Mexico. This pattern is relatively common in to mid to late summer and is referred to as the Southwest Monsoon or the Mexican Monsoon. Although it has been around intermittently for a couple weeks, today it is being combined with low level moisture from the Great Plains. That’s why we are in an somewhat enhanced risk that some thunderstorms may produce high rainfall rates.

Cooler this weekend, with some thunderstorms

8 AM MDT, Saturday, July 19, 2019


When I blogged a couple days ago I said that Saturday may or may not see the continuation of the heat wave. Now it looks like Saturday will see a cold front pass through, probably by morning in Cheyenne and then morning to afternoon as you move south down the Front Range. So today will likely be the last in this stretch of days near 100, and then it will be 15-20 degrees cooler for high temperatures by Sunday.


There should be an increase in moisture behind the front, so expect some areas of clouds and thunderstorms Saturday and Sunday, especially afternoon and evening.

Heat Wave into Saturday

11:30 AM MDT, Wednesday, July 17, 2019

Hot and dry weather are in store through Friday, and possibly extending into Saturday. The atmosphere is quite dry so we can’t rely on the cooling from afternoon thunderstorms over the next few days. A cold front should slip through the Front Range region late Saturday resulting in a bit cooler weather on Sunday. The air mass behind that front should be a little moister too, so the chance of scattered thunderstorms may return Saturday evening and Sunday.


The record highs for today, Thursday, Friday, and Saturday in Denver are 102, 99, 101, 105, and in Boulder today through Saturday shows records of 98, 100, 100, 100. There is a small chance we could reach one or two of these, and a good chance we will get very close.


The weather pattern for this heat wave is a little odd. The atmosphere (including the upper air) over the Front Range is not unusually hot, but the lower levels are coming from the Desert Southwest and thus the near record readings. Next week the atmosphere is likely to be a bit warmer, but the lower levels won’t be coming from the desert, and some monsoon moisture may increase the chance for afternoon clouds. So although hot weather is likely to return after a brief cool-down on Sunday/Monday, it appears it won’t get quite as hot as the next few days.

Typical July weather for the 4th

3:50 PM MDT, Tuesday, July 2, 2019

Wednesday through Friday are likely to see typical early July weather in the region. For Denver, Boulder, Colorado Springs, and Fort Collins that means afternoon high temperatures in the mid 80s to low 90s. The chance for afternoon thunderstorms is likely to decrease Wednesday and Thursday, so some areas may get by with no rain at all.


As we go into the weekend, the pattern won’t change much except that the chance for afternoon thunderstorms might increase again which will shave a few degrees off the high temperatures.

Summer weekend: some heat, but some clouds and thunder too

2PM MDT, Friday, June 28, 2019

Today may be the hottest and driest of the next three days. Temperatures along the urban corridor on Saturday are likely to exceed 90 again in most areas, but there will be a bit more moisture in the atmosphere which means that some clouds and thunderstorms might take the edge of the heat during the afternoon in some spots.  On Sunday a little more moisture in the atmosphere will likely lead to more widespread thunderstorms in the afternoon and evening. Afternoon temperatures on Sunday probably won’t get all the way to 90 for many areas, but it should still be a warm day. That pattern is likely into early next week: near average temperatures and some afternoon and evening thunderstorms for some spots.