Tag Archives: Monsoon Season

Colorado Weather, Thornton Weather

Thornton gets pounded by nighttime storms bringing hail, wind and flooding rains

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Lightning strikes east of 120th Avenue and Fairfax during Tuesday night's storms.
Lightning strikes east of 120th Avenue and Fairfax during Tuesday night's storms. View more images in the slideshow below. (ThorntonWeather.com)

For eight days in a row monsoonal flow fed thunderstorms have struck Thornton and Tuesday night brought arguably the best show yet.  Heavy rain, hail, gusty winds and an extraordinary amount of lightning roused residents soon after nightfall.

Storms initially formed in the afternoon and were focused south of Denver in Elbert County.  Near Kiowa, Elizabeth and Agate hail up to 1 3/4” in diameter was recorded.  The slow-moving storms deposited as much as five inches of rain near Agate.   Three twisters were reported in Elbert County but no damage was realized.

It appeared for a time that Thornton was going to escape the intense weather but once the sun went down the picture changed dramatically.  Seemingly out of nowhere a storm cell popped up at around 9:20pm and moved across the north Denver metro area.

Heavy rain fell across a large part of the area from downtown northward to Thornton.  1.76 inches of rain was recorded north of downtown Denver at DenverWX.com as the storm passed through.
Street flooding was reported across the surrounding areas causing difficulty for motorists.

Here in Thornton we were pounded with heavy rain and a great deal of pea-sized hail.  ThorntonWeather.com recorded its first inch of rain in only 14 minutes and the storm total for the overnight storm was 1.90 inches.

Strong winds also brought down trees and power lines knocking out power to nearly 10,000 Denver area residents including some in Thornton.  Xcel Energy reports power has been restored to most areas this morning.

Denver International Airport recorded a thunderstorm wind gust of 66mph shortly before 10:00pm.  A ground stop was issued and all flights were temporarily delayed while the storm moved through.
Forecasters had predicted a late and shorter than normal monsoon season due to La Niña’s lasting effect – that however has not proven to be true.

Monsoonal flow pulling in moisture from Mexico started earlier than normal this year.  Tuesday marked the eighth straight day for thunderstorms in the Denver metro area and the current weather forecast has at least a chance for storms through the weekend.

To date Thornton has recorded 4.22 inches of precipitation during the month of July.  This far exceeds the Denver historical average of 2.16 inches for July and with the month less than half over, chances are we could achieve ‘top 10 wettest’ status by the end of the month.

Colorado Weather, Thornton Weather

Monsoon season arrives early, brings heavy rains to Thornton area

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A common scene this past week - thunderstorms develop over the Denver area. (Twitpic / CodyCrouch)
A common scene this past week - thunderstorms develop over the Denver area. Watch video of the recent street flooding in Thornton below. (Twitpic / CodyCrouch)

La Niña is winding down and normally we would expect a drier than normal monsoon.  Mother Nature however has other plans as she not only brought the season to Thornton early, it came with a vengeance this week.

In a presentation that just came out at the first of the month, the National Weather Service discussed the coming monsoon.  At that time forecasters predicted a drier and shorter than normal monsoon for the Colorado Front Range.  Thus far it has been anything but.

This past week copious amounts of moisture have streamed into Colorado.  Coupled with daytime heating leading to a good deal of atmospheric instability, thunderstorms have been a daily occurrence.  Strong winds and heavy rain have occurred virtually daily.

Over the past five days Denver has recorded 1.78 inches of rain at the city’s official monitoring station at Denver International Airport.  Closer to where population actually lives even greater amounts have been seen.

Here in Thornton we have recorded 1.98 inches of rain over the past five days.  Other amounts over the same period recorded at nearby stations include 1.79 inches in Arvada, 3.18 inches at Reunion in Commerce City, and 3.06 inches in north Denver.

On Friday evening, a slow-moving thunderstorm dumped heavy rain on the southern parts of Thornton.  Video footage from storm chaser Tony Laubach (below) shows the end result as streets in the area of I-25 and 84th Avenue were flooded.

Is there an end in sight?  Not in the immediate future.  For at least the next few days atmospheric moisture will continue to be in abundance and we will continue to see the same general pattern.  By mid-week we may see some drying but we can’t entirely eliminate the threat of afternoon thunderstorms.

As always you can get the latest Thornton forecast here.