Joe’s Weather Blog: Be Weather Aware early Saturday (FRI-6/1)

There’s good news and some not good news (depending on your feelings on heat). The good news…there is a break in the uncomfortable weather coming for a few days…the bad news…I’m increasingly concerned about some serious mid summer heat lasting for quite some time after this little break we’re about to get. It may not be a heat wave per say…but it could be more 90s…and IF we don’t get into a flow where we become vulnerable to thunderstorm complexes…it could be very dry as well.

More on that on Sunday…meanwhile today I’m focused on the upper Midwest and the northern Plains area. Storms will be popping soon and moving towards the SE. There may well be KC implications before daybreak.



Forecast:

Tonight: Mostly clear through early Saturday morning. Warm as well. 70s for most of the night

Saturday (3AM-10AM): The main window for rain chances in the KC region including the potential for severe storms with strong wind gusts of over 60 MPH. Not a slam dunk as the storms that move this way will be fighting a LOT of warm air above the surface BUT there is a TON of instability that the storms will be able to tap into despite the night hours.

Saturday (late morning onwards): I think we should be drying out. Not as hot with highs in the 80s

Sunday: Nice…cool start…50s(!) then a nice afternoon with highs in the 80s (still above average though).



Discussion:

So the heat is still raging as we kick off the month of June. May ended up #2 in rankings, in terms of the hottest ever in KC for May. Many areas though saw there hottest May temperatures, on average, for the month. St Louis, Columbia, Springfield, St Joseph and a few others were toasty.

In KC…the last time it was hotter was in 1962.

Topeka and Concordia all finished #1 as well and there were others too!

Onwards…

Let’s talk thunderstorms…because they COULD be an issue in the wee hours of Saturday…perhaps even waking you up with the loud cracks of thunder that will be associated with them.

The SPC has put the region under a slight risk of severe storms…with higher probabilities NW of KC proper.

This is based on the likelihood of strong and severe storms developing later today and this evening in the northern Plains southwards into Nebraska. These storms will move towards the SE and ESE…and threaten N MO (for sure) and KC (high chances) overnight.

Here is the HRRR portrayal of the potential development and evolution of the storms..via IA State.

There are some interesting things in this set-up overnight…

  1. there will be a LOT of instability hanging in the region overnight. Typically when the sun goes down there is a stabilizing effect on the atmosphere BUT because we have built up a ton of heat today…and because it’s going to stay pretty warm overnight (and stuffy), while the air nearest the ground will be stabilized..aloft there is going to be somewhat unusual instability just hanging out. I want to illustrate that by showing you the MUCAPES (Most Unstable Convective Available Potential Energy) via Pivotal Weather

MUCAPES are rather helpful in overnight scenarios especially I think They show the storng instability nicely and when you see values between 3000-4000 in western MO and NE KS…you should pay attention. Compounding this is that the storms that we expect to form will be moving INTO this strong instability…that is the concern

2. It’s not that simple though…as this instability will be overwhelming…there is also the problem of the cap which is going to be putting up a fight with the storms coming into it. Remember the cap is a layer of warm air…mostly in the 10,000 feet and below region (give or take). The cap will be unusually strong overnight. We look for the temperatures at close to 700 mbs, or about 10,000 feet, to help us determine the strength of this cap. The next map shows these temperatures in °C. 10°C = 50°F. Tonight we have values of 13-14°C or just under 60°F. That’s a pretty strong lid especially for June 1st.

3. The strong chance that these storms will alter the atmosphere around them enough to allow the cap to weaken and then break with whatever outflow or atmospheric changes the complex can generate on it’s own. This is the “forecast buster” part of the forecast. IF the cap holds strong enough, from KC southwards…the storms may be more of an issue in N MO than in KC (with a heck of a light show to our north). IF the cap weakens enough and the storms can bully through…the main concern would be 60-80 MPH winds…and those winds could do damage.

4. It’s worthy enough of a situation that, at least from looking at things this afternoon…it’s worth upgrading our region to WEATHER AWARE status after 3AM or so (earlier for far NW MO and NE KS)

5. More specific timing…12-3AM from about St Joe northwards…3AM-6AM or so for the KC region (in terms of the best chance of the damaging winds) and IF the storms hold together farther south and east after 6AM or so.

6. The main threat continues to be damaging winds in the viewing area and with the overnight timing and the fact that this is a Friday and folks may not be paying attention to the weather as closely…this could surprise many…

7. Odds are these are very electrical storms too depending on how long they hold together as they come into the I-70 corridor area.

8. The area of concern this afternoon is already starting to light up…

Let’s add in some regional and local radars too…

OK so you have all the data for now…check in with MT later tonight (especially) and let’s see how things evolve.

Our feature photo was sent in by Jackie Strydom from Clinton, MO a couple of weeks ago. Fitting for the forecast.

Joe

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