KANSAS CITY, Mo. — A powerful storm complex yesterday, that actually started in Montana, pushed through the upper Midwest, including South Dakota, last night and created dozens of reports of severe winds. The storm also generated a cold front that plunged into the region overnight.

I mentioned yesterday afternoon how something like this can alter, and in the end, change the weather pattern for our area, and “surprise” with sudden rain chances and a decrease in the heat.

This morning, there are showers breaking out on the north side of the metro, nothing severe, but a sign that the derecho indeed has altered our local weather.

Just fascinating.

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Kansas City Forecast

Today: Variable clouds and hot, still humid as well. Highs 90-95 degrees.

Tonight: Another chance of some storms/showers. It looks like the chance is still low. Aside from that, breaks in the clouds and muggy. Lows in the mid-70s.

Tomorrow: Partly cloudy and hot and humid with highs in the lower 90s. Small rain chance.

Friday: A slightly better chance but nothing overwhelming. Not as hot though with highs in the upper 80s.

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Discussion

This thing was impressive yesterday. The mesoscale convective system ended up being classified as a derecho as it moved across the northern U.S.:

Dozens of severe thunderstorm warnings were issued:

And the wind swath was impressive, peaking at close to 100 mph.

There was some 4-plus-inch hail as well mixed in. The derecho weakened in eastern Iowa.

What it did for us was to push out an outflow boundary that is basically rain-cooled air from the thunderstorms that form. This boundary has made it to the south side of the area.

This morning, lots of clouds and even a few brief scattered showers have formed on the northside of the metro.

You can see the effects of the derecho and how it has rearranged the atmosphere to some extent.

It will play a role perhaps today in knocking down the heat just a bit, depending on how long the clouds linger.

This complicated the extent of the excessive heat warning that has been in effect for many areas from the metro south and eastwards into St. Louis. Yesterday, STL hit 101 degrees.

The counties in deeper pink are under the Excessive Heat Warning while the counties in orange are under and advisory. Northern Missouri has been removed from these higher risks.

Don’t get me wrong, it will still be hot and humid today, but perhaps we get a break into the early afternoon with the clouds helping the cause and then make a later afternoon run into the 90s.

The atmosphere has been temporarily rearranged.

The outflow came through while you were sleeping and sort of is fading away now. The winds up at KCI switched from the south to the north around 1 a.m.

Here’s radar. There are other areas of rain out there, one from another complex that wasn’t as strong on the Kansas side.

It just shows you that sometimes even when the weather pattern is trying to be so very hot (although KCI has only hit 94 degrees so far with this stretch), things can happen that alter the best laid plans.

To be fair, the south side has been about 3-5 degrees hotter these last couple of days.

I don’t think we’ll see much more rain today.

When will it rain again in Kansas City?

The next more significant change in the weather will be a somewhat stronger cold front that should move into the region for the weekend. The overnight data now brings this front into the area early on Friday, and that may not be helpful in getting storms to form locally because it’s coming in during a time of less instability to work with.

If the front is 12 hours slower, something can happen perhaps, but that timing isn’t too great for much coverage of the rain potential.

What it will do though is cool us down to average temperatures and cut the humidity down as well.

Instead of dew points in the mid-70s, we’ll see a reduction into the mid-to-upper 60s. It should be noticeable, and while still “humid,” it won’t be oppressive.

This leads to a problem though: A somewhat dry stretch with scattered rains over the next couple of weeks is showing up. No organized areas of rain may get triggered around these parts. Model data, while not totally dry, isn’t too thrilling for rain.

EURO forecast trends
GFS forecast trends. Model averages are close to 1″ or so…over the next 2 weeks.

Not great.

We will be vulnerable to cold fronts though, so maybe we can get something from those next week. Also it appears next week won’t be overly hot, except potentially for Monday.

The “heat wave generator” will be migrating westwards towards the western U.S. during the middle of the week. You can see the difference as we go up to around 18,000 feet or so. Notice today the upper-level high is close by, sort of flat looking.

Then a week from today, big position change.

This places us into north-northwest/northwest flow, which can create clusters of storms in the western Plains that try and run southeastwards. It will also allow the dew points to dry out a bit, meaning cooler overnights and likely less hot days… more 80s than 90s it appears. Again, that’s for next week.

David Van Fleet has the feature photo from Buckner today.

Joe