Joe’s Weather Blog: Saturday is another “Weather Aware” day in KC (FRI-5/18)

Good afternoon…another warm day in KC as the stretch of above average temperatures continue. This is the 2nd warmest start to the month of May in KC weather history…dating back to the 1880s! 1962 was warmer through the 1st 17 days…meanwhile I continue to watch the data for Saturday and the risks of severe storms in the region…FOX 4 Weather has upgraded our area to WEATHER AWARE status. This means I want you o pay more attention to the unfolding weather scenario for tomorrow…especially later in the day and tomorrow night. Also for those who live north of KC…please be extra aware of the changing weather later tomorrow as severe storms, including perhaps a few tornadoes are possible as well.



Forecast:

Tonight: Fair initially then increasing clouds after 12AM. There is a chance of some sort of fading line of storms/rain to move into the area near daybreak for several hours. Temperatures will drop back into the 60s

Saturday: This will be somewhat of a changing forecast. We’ll need to see how the AM leftovers affect the later PM activity…so there are several things to work out tomorrow. The highest rain chances appear to be before lunch and then again very late in the afternoon through later tomorrow night. The 2nd part of that is the main severe weather risk. ALL forms of severe weather are possible. There could be some isolated tornadoes as well…where the best set-up for tornadoes will end up being will be figured out Saturday afternoon BUT areas from KC and north should be aware of the developing situation. Hot and humid with highs well into the 80s

Sunday: There may be some AM showers leftover showers then variable clouds and not as hot with highs closer to 80°. It may be cooler depending on how much sunshine we don’t or do get.



Discussion:

Quite a bit to pay attention too concerning the severe weather risk. More on that in a few minutes but 1st a recap of the month of May so far…through 17 days at least.

As mentioned at the top of the blog…this is the 2nd warmest start to May in KC weather history. Take a look.

That’s pretty impressive and what a swing from the month of April!

It’s been summer-ish out there for sure! Take a look at the average highs (only) through the 1st 18 days of the month…

83° when the average is around 72° is pretty strong and will definitely affect your pocket book in a few weeks IF you’ve been running the A/C as we have in the Lauria household.

There are no strong signals for any prolonged “coolness” coming either. A day or two here and there (maybe) but overall pretty warm weather is expected for quite some time.

Severe weather update…

I continue to have interest in how Saturday will play out in the region. There are caveats as usual with this set-up, particularly how the activity that may or may not be an issue before daybreak from KC westwards affects what happens later in the day and the amount of instability that will be realized.

On the assumption that whatever happens in the AM doesn’t affect the later PM…and the atmosphere makes a nice recovery after lunch with more sun=more heat= more instability…we should set up for some rather nasty storms in the viewing area. Exactly where the set-up is maximized also remains to be seen.

When looking at the data this morning…it appears to me that ALL forms of severe weather are on the table including hail/wind/tornadoes and with a lessor flooding concern. The tornadic risk can’t really be discounted, even as far south as the KC metro area. When I look at the atmospheric profile in the later afternoon tomorrow, likely ahead of whatever were to form and move in…you can’t help but notice the clockwise turning of the direction of the winds as you move up into the atmosphere, especially from near the ground upwards to about 18,000 feet or so.

Let me show you the NAM output…

What I want you to pay attention to in the graphic above is how the winds start near the ground from the SE and as you go up through the atmosphere in that 5-7PM window…the winds turn from the southeast…to the south…to the southwest. That turning, or as we say in the weather business, “veering” in indicative of what we refer to as wind shear. Thunderstorms LOVE wind shear…they get stronger because of it…and the directional wind shear will be a favorable aspect in the severe weather potential tomorrow late day. The graphic on the right hand side shows this.

On the lest hand side of the graphic above is the speed shear…or the increase with height of the wind speeds. In the situation tomorrow…that aspect isn’t as powerful in the set-up. when both are together…it’s a much bigger concern. When it’s one more than the other…it’s still worth paying attention too in my opinion…and that is the case on Saturday afternoon/evening.

The SPC folks are watching this as well and in the the afternoon update have extended the “enhanced” risk of storms.

The set up tomorrow will be somewhat dependent on several things that will be figured out as the afternoon comes into play. 1) the instability. I think we should have that as long as we get warm and humid and whatever happens in the morning doesn’t mess up the atmosphere too much…2) the location of the warm front. This may be anywhere from around KC to near the IA border. I’d be especially concerned about it’s location in the late afternoon. Storms that fire near that warm front will encounter an atmosphere potentially more conducive to allow those storms to rotate near that warm front. IF that front is closer to I-70…that is troubling for closer to the KC area, in terms of the potential for rotating storms…rotating storms are capable of producing larger hail and also tornadoes. IF the front is farther north…the tornadic threat may be farther north….3) will there be a small area of low pressure developing along the cold front pushing into the area? This too can enhance the chances of rotating storms…especially near and east of the low pressure center.

So there are several things that I’ll be watching tomorrow as the day unfolds.

Finally…yesterday I wrote about the interesting phenomena called a “meteotsunami” that occurred in a few areas back east from the severe weather outbreak that happened on the 15th. Today during the 9AM newscast I did a bit of a weather demonstration about why that happened.

Our feature photo today is from Daphne Burns...nice shot from the other day of the towering cumulus congestus clouds.

Next update sometime Saturday...maybe before lunch...if not by 2PM.

Joe

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