Updated Thu Jul 28, 2022 12:00pm MST | Published Thu Jul 28, 2022
- Very active weather day today. Widespread storms and precipitation in the high country. Some severe storm potential to the east of the Divide and in the high plains.
- Active tomorrow as well, but not quite as widespread – though still a washout in southern Colorado. Drier in northern Colorado particularly. Could be almost constant rain in parts of southern Colorado from tonight, into that morning, and into the start of afternoon thunderstorm initiation.
- Less storm coverage on Saturday and Sunday as drier air and subsidence works its way into Colorado as ridging rebuilds overhead. Still, significant storm activity in southern Colorado and isolated/scattered storms in the rest of the high country. In the northern/central Colorado mountains, you can follow the “down to treeline by noon” rule.
- Not enough data yet to give the nod to Saturday vs. Sunday, in terms of thunderstorm potential.
- Monday provides an opportunity for more committing objectives in northern Colorado but still not totally storm-free. Scattered storms continue in southern Colorado. This will likely be driest day before another long stretch of significant monsoonal moisture.
- Another monsoonal moisture surge Tuesday/Wednesday as high pressure sets up to our east.
- Then, another surge likely for the following weekend.
Lightning Risk Grids
Retrospective and Current Conditions
For those of us on the Front Range, the past two evenings have been quite exciting! Many folks along the I-25 corridor were treated to a display of nonstop lightning. Areas like Estes Park picked up significant hail accumulations, and some folks near Fort Collins had their cars damaged by large hail.
A question was posed this morning:
In some of the video posted from last night’s storm, it almost looked like there were wall clouds and some rotation. … I don’t believe there were any tornado watches/warnings or sightings - but just curious, was this the type of cell where it was a possibility?
There was indeed a bit of rotation and structure on the cell over Boulder / west Denver. However, wind shear was not strong enough to really whip this into the sort of beast that could drop a tornado – and in general, structure was not too impressive despite how strong the updraft was. But, with such a robust updraft, there’s always the possibility that it could wander over a boundary and essentially suck up a small vortex and transform that into a short-lived landspout tornado.
When thinking about precipitation, the past two days have been very good to the Front Range, high plains, and southern Colorado – coincidentally, most of the areas in the largest drought.
Colorado has been in a prime spot in regards to the large-scale atmospheric pattern. We’re getting a lot of low-level monsoonal moisture from the southwest, as is fairly typical this time of year. You can see that in this morning’s satellite loop:
Additionally, the ridge that is typically overhead of the western United States has broken down as a few shortwaves have swept through the region. For Colorado, these have brought cold fronts and moisture at mid and upper levels, resulting in a very saturated water column over the Front Range, large scale lift, and some decent boundaries which have helped tap into a juicy convective environment like we saw the past couple nights.
This remains the case for today and tomorrow. Notice the lack of yellows overhead, and a large low pressure system to our northeast – the atmosphere above Colorado is pretty saucy right now!
Forecast Discussion: Today and Tomorrow
Today should feature widespread storms across Colorado thanks to a plethora of low and mid level moisture. In fact, much of the desert southwest has flash flood watches in effect.
Storms are already starting to pop over the high country, with widespread coverage expected late into the night most everywhere. In the San Juans and Sangres, should be a total washout with large areas of precipitation continuing into Friday morning.
For the Front Range, we’re expecting the cloud deck to break down and strong cells to initiate over the foothills. These could have some hail cores, and slowly wander east (with flooding concerns due to the rate of precipitation and slow motion) to successfully step down over the I-25 corridor, with hail still a possibility.
The best chance for heaviest precipitation and stronger storms in Colorado maybe over the foothills and just east – the orange colors in this graphic:
In southern Colorado, the rain may not really stop before the next round of afternoon thunderstorms on Friday. With drier air working down from the north, things may be a bit more isolated in northern Colorado.
In general, a little less moisture in general across the state, with less dynamics, so probably not as many afternoon thunderstorms as today – but still a large number of them. With how the saturated water column is, by later in the afternoon / evening, storm cells will be producing some pretty outsized swaths of rain across the mountains.
Short range ensembles definitely favor central and southern Colorado for copious amounts of precipitation:
Forecast Discussion: The Weekend
Ridging starts to redevelop this weekend, and we’ll see temperatures become more summer-like.
Drier air and subsidence behind the passing shortwave will help to limit thunderstorm development into Monday, particularly in northern Colorado. Of course, that’s relative to the fact that we’ve been experiencing widespread heavy precipitation across most of Colorado – so while storm coverage may be more scattered/isolated, definitely not looking dry by any stretch of the imagination.
You’ll notice on the same short range ensemble product for Saturday, the yellows and reds are gone:
And even less so for Sunday:
Outside of southern Colorado, heavy precip may not be much of an issue at all this weekend, just lightning. Storm cells will be small, but likely pretty electrical, so keep an eye out if you’re headed above treeline. Unlike some days we’ve seen recently though, you should be pretty safe following the standard “down to treeline by noon” rule. The San Juans and Sangres may be an exception, with lingering moisture in the morning, better storm coverage, and earlier initiation.
In our past forecast, we were also concerned about the potential for smoke to enter our area, and despite some little wisps of it, it looks like the pattern (and upwind fire activity) is unfolding in a manner where we likely wont see any significant impacts.
Forecast Discussion: Next Week
Monday looks particularly dry and this may be your best opportunity to do something more committing in northern Colorado before we proceed into another stretch of better storm coverage. In southern Colorado, still some decent storm chances, but areas along the Front Range likely wont see more than an isolated storm or two.
For the rest of the week, high pressure becomes centered over the southern plains which means we’ll draw several surges of monsoonal moisture into Colorado. In fact, ensemble guidance has a strong signal for wetter-than-average conditions in Colorado for at least that next week or two. Considering our thoughts on the overall large-scale pattern and monsoon season in general, this is quite fortunate as we have been expecting the tap to get shut off as we get into August.
A strong surge looks likely on Tuesday/Wednesday, and then another seems progged for the following weekend. Per usual, this has a larger impact on Colorado’s high country (particularly the San Juans) than it does on the Front Range and high plains.
Temperatures follow suit as well, with cooler temperatures in southwestern Colorado and hot temperatures in the Front Range.
Stay tuned to our social media, we’ll likely be posting about weekend storm potential.