Joe’s Weather Blog: Remain WEATHER AWARE tonight in KC (SAT-5/19)

I will probably get two blogs out today…this one will be a shorter one though, but I want to have something out for you this morning…basically updating the situation which remains somewhat in flux for tonight in the KC area. There hasn’t been a big change in the latest thinking from the folks at the Storm Prediction Center (SPC) with the exception being a farther southwards extension of the “enhanced” risk of severe storms so that it encompasses most of the viewing area. Again remain WEATHER AWARE tonight…especially after 4PM in NW MO and NE KS…and after 6-7 PM in the KC Metro area.



Forecast:

Today: Periods of rain this morning through at least 10-11AM or so…then a lull in the afternoon. Temperatures will be sluggish this morning but should pop into the 80s in the afternoon with enough sunshine.

Tonight: Be WEATHER AWARE. Storms are still more probable than not and those storms should be strong>severe. All risks of severe weather will be with us including large hail/stronger winds/and perhaps some brief tornadoes as well. The main tornadic threat is in NW MO and NE KS…although closer to KC we need to be on the lookout for those mesovortex type tornadoes IF there is a line that comes together and moves through the area. There are still questions how this will play out. Lows in the 60s

Sunday: Perhaps a few leftover AM showers…then some isolated PM stuff possible. Not as warm with highs in the 70s



Discussion:

Let’s start with radar from the NWS in Pleasant Hill…

We’re going to be in and out of the rain this morning…lingering till near or before lunch I think. Strongest AM storms should be south of the KC metro area…some of that activity may contain some small-ish hail as well.

The activity this morning is going to mess around with the atmosphere. I’ve identified several little waves out there that will leave behind some residual boundaries and areas of stability. This is a complicating factor for instability.

Next up is the visible satellite picture because the longer we have the clouds the longer the unstable air takes to build back up, especially in a worked over atmosphere from the morning activity.

The picture above should auto-update for you.

There is clearing this morning occurring in south central KS and especially OK. That will be rich and unstable air building up out there. We should see more afternoon sunshine…but the clouds will be around for awhile…

Next up is the CAPE product. CAPE stands for Convective Available Potential Energy. The bigger the CAPE value the more instability that a storm can tap into.

The numbers NOT in the blue area show an “uncapped” atmosphere. Those numbers (contoured in RED) will be increasing dramatically later today as the sun does it’s dirty work and makes the atmosphere more unstable.

The main focus for the SPC outlook is from KC northwards…and down the I-35 corridor.

The enhanced area of severe weather means that the storms have a better potential of being more widespread and more intense than in other areas.

It would be considered LEVEL 3 out of 5 in terms of risks.

So about those caveats that I talked about this morning on FOX 4 News…

  1. How long will the clouds linger…how will that affect our local instability later today?
  2. Is the atmosphere messed up now that we’ve had these various waves move through the region this morning
  3. Where will the various features align themselves later today. The stronger risk of tornadic cells appears to be near and north of 36 Highway into N MO and NE KS…BUT as that area comes together…will it slide towards us…and then KC has to worry about those “smaller” fast spin-ups like what happened a couple of weeks ago on that Wednesday night?
  4. How strong will the cells actually get in N MO anyway? Will clouds hamper their instability

What I’m trying to point out is that this is NOT a clear cut scenario today. IF we didn’t have all this AM stuff out there I’d have my engines revved up a bit more about this evening especially in the KC Metro area and earlier for NW MO as well. My colleagues at the SPC are also wondering how things will play out later today and this evening for the region.

“N THE EAST-SOUTHEAST PERIPHERY OF A WEAK/SLOW-MOVING UPPER LOW OVER
THE CENTRAL HIGH PLAINS, A RIBBON OF MODERATELY STRONG SOUTHWESTERLY
WINDS WILL OVERSPREAD A SOUTHWEST/NORTHEAST-ORIENTED FRONTAL ZONE,
WHICH HAS BEEN CONVECTIVELY MODIFIED IN AREAS. ALTHOUGH THE
PERSISTENCE OF EARLY-DAY STORMS AND THE IMPACTS/DISPOSITION OF
OUTFLOWS ARE POINTS OF UNCERTAINTY, CURRENT THINKING IS THAT
SURFACE-BASED STORMS ARE MOST LIKELY TO DEVELOP THIS AFTERNOON
ACROSS EAST-CENTRAL/NORTHEAST KANSAS NEAR A TRIPLE POINT, WITH THE
NORTHERN EXTENT (SUCH AS SOUTHEAST NEBRASKA AND SOUTHERN IOWA) OF
THE SURFACE-BASED SEVERE RISK COMPLICATED BY LINGERING CLOUD COVER
AND A SOUTHWARD-ADVANCING SECONDARY FRONT.

REGARDLESS, DEEP-LAYER/LOW-LEVEL SHEAR ARE EXPECTED TO BE MAXIMIZED
IN THIS GENERAL VICINITY WITH THE POTENTIAL FOR INITIAL SUPERCELLS
CAPABLE OF LARGE HAIL AND AT LEAST SOME TORNADO RISK. THESE
INITIALLY MORE DISCRETE STORMS SHOULD MERGE AND GROW UPSCALE EARLY
THIS EVENING AS THEY SPREAD TOWARD WESTERN/NORTHERN MISSOURI. A
SEMI-FOCUSED CORRIDOR OF DAMAGING WINDS, AND POSSIBLY A FEW
QLCS-RELATED TORNADOES, MAY EVOLVE ACROSS WESTERN AND NORTHERN OF
MISSOURI THIS EVENING. ”

When the SPC refers to the “triple point” that is the conjunction of an area of low pressure…with a warm front extending outwards and a cold front (or a dry line) pushing southwards/eastwards. Typically near and east or northeast of the “triple point” is an area that has the strongest likelihood of seeing rotating storms. It’s not a hard and fast rule, and you still need other factors to come through (instability especially) but it is a favored area.

Where that “triple point” sets up though is a bit in flux because of all this morning activity.

I’m going to finish with the HRRR model. This model will vary from run to run but it MAY gove a general idea about how things play out later today and tonight. (via IA State)

The bottom line is that we’re vulnerable to stronger storms after 5PM today…especially between 7-10 PM or so in the KC region. IF areas farther north get into the action those cells, in particular, will have more rotating characteristics.

I would be surprised IF we’re unstable enough this afternoon to NOT be under some sort of Tornado Watch for this evening especially in KC.

I know there are a lot of things happening today…Royals…graduation parties, Jimmy Buffet…etc. Have a way to get the latest weather information…check in with me on twitter (@fox4wx) for additional updates this afternoon.

Our feature photo comes from Bill Kemper in Clinton, MO from this morning’s activity.

I’ll try and push out another blog update by 2PM or so.

Joe

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