Monthly Archives: August 2018

Generally nice end-of-summer weekend, some thunderstorms

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!

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Moist Tuesday into Wednesday

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.

Chance for T-showers Saturday, cooler Sunday

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.

Perseid meteor shower this weekend

10 AM MDT, Friday, August 10, 2018

The Perseids are one of the two most dependable major meteor showers of the year (the Geminids in mid December are the other). The Perseids are fast-moving which can make them hard to see if you’re not paying attention. But their fast movement also means a lot of energy gets released when they hit the atmosphere, and so they are known for producing some really bright streaks with smoke trails.

 

The peak time is after midnight when they tend to be higher in the sky. Sunday and Monday mornings are both in the peak, but the astronomy websites and journals seem to be more focused on Monday between midnight and daybreak.

 

This year has the added benefit of no moon in the late night and early morning hours. The possible down side is smoke haze from western fires that could dim the display a tiny bit.  But the middle and upper atmosphere flow this weekend will be mainly from the north (rather than west-to-east) so there is hope that we will see clearer skies in Colorado.

 

…and the weather

Dry conditions and average to slightly above average temperatures are expected across the central Rockies region through Monday.

A few strong thunderstorms around eastern Colorado today

12:15 PM MDT, Monday, August 6, 2018

A cold front yesterday evening brought cooler and more humid low-level air from the Great Plains into the Front Range. That should fuel some showers and thunderstorms this afternoon and evening. Many of us will likely get at least a brief shower, and a few spots will probably see a strong thunderstorm with heavy rain and hail. One of the most popular local-scale models (the HRRR) is suggesting that the heavy thunderstorms may stay south and east of Denver, but there is enough uncertainty that I think all of the Front Range should be prepared for the possibility of thunderstorms.

 

There should be another, but smaller, chance for thunderstorms Tuesday afternoon. Then a mainly dry and warm (but not very hot) week is in store for the Front Range. Very hot weather will likely be close by in the western U.S., including western Colorado valleys.

 

 

Wet afternoon, mainly dry and warm weekend

12:30 PM MDT, Friday, August 3, 2018

A weak disturbance with a bit of monsoon moisture is moving through Colorado today and is kicking up more showers than I had expected. So the afternoon and evening are likely to see some sprinkles and showers around, and a few spots could see a brief heavy thunderstorm.

 

The atmosphere should dry out a bit Saturday and Sunday, so expect more sun, warmer temperatures, and only a small chance for a localized thunderstorm. High temperatures Saturday and Sunday will likely be in the upper 80s to low 90s.

 

Next week we are likely to be in a pattern with very hot weather in the West (including western Colorado) and average to a bit cooler the average on the Great Plains. The Front Range region is likely to be mainly warm and dry, but we may get one or two brief periods with a push of cooler air from the east. It looks like one of those cooler spells (with a better chance for thunderstorms) will be Monday.