Thanks to the interplay between a potent trough and ridge, our temperatures will soar into the 80’s to start the third week of May, followed by a late-week “cool” down. Weather stays overall dry but there is some severe weather potential to speak of for eastern Colorado.
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This week’s highlights include:
- Hot and dry to start the week
- Severe weather in far eastern Colorado Tuesday, though our neck of the woods will be largely spared
- A cool down with a better chance of storms to end the week and start the weekend
GOES-East infrared satellite animation from Monday morning
An active day across the nation; 80’s over next few days for the Front Range
This third week of May starts off rather active. Shown in the below figure are several features worth pointing out.
- The first is tropical storm Arthur off the coast of North Carolina, our first tropical system of the season!
- In the Midwest, two semi-connected areas of low pressure are leading to unsettled and chilly weather for the middle-section of the country today and later for the southeastern U.S. the remainder of the week.
- To the far west, a strong and potent trough of low pressure is making its way onshore into California today.
- Where we are is rather quiet but that ridge to our south in northern Mexico will be boosting us into the 80’s today and tomorrow.
Thanks to a combined southwesterly flow from the trough over California and the ridge to our south today (above), temperatures will soar some 10 to 12 degrees higher than they were on Sunday into the middle to upper 80’s. Barring any particularly dense high clouds streaming in from the southwest tied to that trough, we should have no problem reaching these forecasted highs.
It is going to be a warm one again tomorrow, with temperatures likely topping out in the middle to maybe upper 80’s again.
Potent trough advances through Tuesday night / Wednesday
The trough over California advances through the state between late Tuesday and mid-day Wednesday. Shown below is the evolution of the trough from mid-day Tuesday to mid-day Wednesday. The system starts out over western Nevada and tracks northeastward into southern Idaho in the 24-hour period. As the system takes this trajectory, the trough becomes what we meteorologists call “negatively tilted”. This is when the trough is no longer positioned in a north-south direction, but instead the northwest-southeast direction. This transition to a negatively tilted trough is a sign that the low pressure is in a strengthening phase. As the trough passes through during this time frame, we are expecting potential severe weather Tuesday night over eastern Colorado as well as gusty winds in our area Wednesday.
The potential for severe thunderstorms should line up across far eastern sections of our beautiful state tomorrow evening. An accompanying cold front will not fully pass through until later Wednesday, but above normal moisture (below left) coupled to unstable air and favorable wind shear (below right) will set the stage for storms to fire late in the day Tuesday. That is, if enough surface heating can overcome a stable layer aloft. Over the Front Range, we appear to be largely in the clear thanks to dry downslope air in place and a “capping” inversion to prevent storm development. Also, the main lift appears to stay well to our east. We certainly could not rule out an isolated storm tomorrow, but we think that will be few and far between.
The front makes its way through during the afternoon hours on Wednesday. As the system tracks into Montana and southern Canada, it will still have a strong jet streak connected to the trough. Flow from the south-southwest for the middle of the week will lead to a tight height gradient between the higher terrain and the Plains allowing for wind gusts over 30 mph during the afternoon hours. These gusty winds across the High Country as well will lead to Red Flag conditions Tuesday and Wednesday. Temperatures will likely be a tad cooler than the earlier part of the week thanks to deeper mixing from above the surface and with a cooler airmass slowly building in…low 80’s look good right now. There may be a slight chance of a storm again on Wednesday but the action should again generally stay over eastern sections of Colorado.
Cooler but with chance of storms to end the week
The cool front fully slides through come Thursday (below). However, much of the cooler air will skirt to our north, largely sparring us from getting as cool as Wyoming, for example. Nevertheless, the airmass does cool off, a roughly 5 degC drop in the low-levels. This would support highs in the low to middle 70’s for Thursday. However, we should point out, if the trend in the forecast guidance shifts a tad further north than what is shown currently, temperatures could be warmer than currently anticipated – though still in the 70’s.
Although not a super promising pattern for storms on the upcoming Friday, another trough appears poised to track southward and into the area late Friday and Saturday. With the flow turning southwesterly, a slightly better fetch of moisture may increase the storm potential, especially for the upcoming weekend. Temperatures should end the work week back into the mid to upper 70’s.
Forecast Specifics:
Monday: Some passing high clouds from time to time, but plenty of sunshine with highs very warm in the mid to upper 80’s on the Plains and middle 70’s in the Foothills.
Tuesday: Morning sun giving way to increasing clouds and just a slight chance of a late afternoon or evening storm. Highs in the mid to upper 80’s on the Plains and middle 70’s in the Foothills.
Wednesday: Partly cloudy and breezy with gusts up to 30 MPH. A storm or two may clip the far northern Front Range towards the Wyoming border. Highs near the lower 80’s on the Plains and the upper 60’s in the Foothills.
Thursday: Increasing clouds and cooler with a slight chance of afternoon and evening storms. Highs in the lower to middle 70’s on the Plains and upper 50’s in the Foothills.
Friday: Partly cloudy with a slight chance of late-day storms and temperatures in the mid to upper 70’s on the Plains and low 60’s in the Foothills.
The Weekend: An increased chance of storms appears on the horizon for the upcoming weekend with another trough of low pressure advancing through, along with cooler and more seasonal temperatures.
High Country: Breezy and warm conditions will be the norm over the higher terrain to start the week, leading to Red Flag conditions over southern Colorado due to the drought in that part of the state. Isolated storms are possible Tuesday and Wednesday. Breezy and cooler conditions take over for the remainder of the week. Check SummitCAST for daily updated forecasts for more than 120 mountain hiking destinations across Colorado.
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