Less hot and more moist is on the way

1:00 PM MDT, Thursday, June 14, 2018

We are likely to enter a period this weekend with cooler temperatures and a better chance for periods of clouds and thunderstorms across the central Rockies, including the Front Range region. The change might start out slowly Friday or Saturday and become more noticeable Sunday and Monday.

Friday-Saturday

It should still be quite warm in most areas, but some moisture from the tropical Pacific will increase the chance of late day cloudy periods and some localized showers or thunderstorms. The pattern is an early taste of the Southwest monsoon.

Sunday-Tuesday

A cool front from the north may arrive by late Sunday bringing in cooler weather. Cloudy periods late Sunday into early next week may be more numerous and there may be a late day period with more organized coverage of showers and thunderstorms on Sunday or Monday.

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Hot weekend, cool front Sunday night

5:45 AM, Friday, June 8, 2018

We have a hot summer weekend coming up with low elevation temperatures topping 90 and probably reaching mid 90s in a number of areas. A cool front Sunday night should trim about 10 degrees off the high temperature for Monday, but that’s still a warm day.

 

No organized areas of rainfall are expected and even isolated showers will be hard to come by. The main weather may be increasingly windy conditions both before and after the cool front Sunday afternoon and Monday. Those winds may enhance the risk of wildfires especially in the western and southern parts of the state where the vegetation is drier.

Nice early summer weekend

11:30 AM, Friday, June 1, 2018

A weak and mainly dry cold front will be passing through the Front Range region late today. Its main impact will likely be to kick up the wind a little today and reduce the temperature a little on Saturday. Sunday will probably be a little warmer than Saturday.

This is the time of year when a small chance of afternoon thunderstorms often exists. I expect it to stay dry today and tomorrow. The chance for thunder returns on Sunday, but it is a low chance for any one location. Above average temperatures are likely as we go into the early part of the work week.

Afternoon showers and thunderstorms today

8:45 AM, Monday, May 28, 2018

Many parts of the Front Range region will likely experience thunderstorms this afternoon or evening. The greatest risk of severe weather (hail or a tornado) is out on the eastern plains, but even in the urban corridor a few areas can get damaging hail & wind, and brief heavy rain. After a few days with relatively mild temperatures this week, very warm weather is likely to return by Thursday.

Very warm weekend, especially Saturday

Noon, Thursday, May 24, 2018

For the long holiday weekend it looks warm and dry for Colorado and southern Wyoming. The chance for clouds and an afternoon thunderstorm may be on the increase by Monday, and temperatures may be just a little less warm. Daytime maximum temperatures Friday-Sunday in the Front Range urban urban corridor are likely to range from the mid 80s to around 90 (a little cooler in Cheyenne) with Saturday bringing the best chance for topping 90. Unlike northeastern Colorado, other parts of the state have been somewhat dry in May and those areas may see elevated wildfire risk this weekend.

 

Record warm?

We should get close to some of these records, and it’s not out of the question that there may be a few locations around the region that set a record high. Record high temperatures in Denver are:

Friday 91 (1964), Saturday 95 (1942), Sunday 93 (2006),

and for Boulder:

Friday 87 (2013), Saturday 91 (1969), Sunday 92 (2006).

Update: Reduced flood risk

7:00 AM, Saturday, May 19, 2018

The potential for additional heavy soaking rain today along the Front Range is low. Heavy rain is occurring out on the northeastern plains and the western edge is moving toward the northern Front Range but the heaviest rainfall is likely to stay north and east of Fort Collins and Greeley (Cheyenne will probably get a period of moderate or heavy rain). For the Denver-Boulder area the day will be mainly cloudy with some intermittent rain, but total amounts are not likely to cause problems.

 

Sunday should be milder and drier, but still with the chance for a few afternoon showers and thunderstorms.

Rain; a portion of the area likely to see heavy rain

1:15 PM, Friday, May 18, 2018

Parts of the Front Range region are in for a lot of rain today and Saturday, with wet snow above treeline. There are two phases of rainfall expected. Phase one will be in the form of showers and thunderstorms this afternoon and evening, some producing intense rain and hail.

Phase 2 (after a possible lull during the night) will come later tonight and Saturday with a soaking rain. It’s possible that not all areas will get a heavy soaking rain. The chances are greater north of Denver than they are south of Denver. I’d say the additional heavy rain is likely over Weld and eastern Larimer counties into southeastern Wyoming. But the risk of additional heavy rain exists throughout the Denver-Boulder area later tonight and tomorrow. Where the heavy rain hits there could be more than a month’s worth by Saturday evening (an average May brings about 3 inches total in Boulder and 2-3 inches in Denver).

Watch out for localized street flooding and the potential for creeks to spread out of their channels in some places. The Saturday morning Farmers Markets may be in for the second wet Saturday in a row.

Model Guidance

For those interested, the GFS is a good, reliable model but not always the best at resolving the terrain influences. That one brings heavy rain to the entire Front Range region from the Denver area to Cheyenne. Many of the models that have better terrain representation (the NAM and different versions of the WRF) keep the most intense rainfall amounts just to the north an east of the Denver-Boulder area (but watch out Fort Collins and Greeley). I wouldn’t dismiss the GFS solution even though I’m a little suspicious. Stay alert.