Suchan Says: Cold Front Brings Showers or T-Storms

Unseasonably mild weather continues across the region but we are now less than 24 hours away from our next autumn cold front to push across.  As it approaches later in the day, showers or some fast moving squally thunderstorms will be possible with brief strong wind gusts, small hail and some lightning.

Ingredients for a “widespread” severe weather day are not there but there’s certainly enough on the table for an isolated severe weather risk.  The most impressive feature of note, a very strong wind field from the surface to upper atmosphere combined with strong forcing to develop storms.  The key “lacking” feature is a lack of strong instability parameters.  We appear to only be weakly unstable late in the afternoon which impacts storm updrafts greatly.  It’s a classic case where the severe weathe recipe is “out of balance” with too much shear compared to the amount of forecast instability.  When the two are aligned, big severe weather days are likely.

To illustrate these points, here is a forecast sounding for mid to late afternoon in Kansas City today.  Lots of wind shear but rather poor instability offered by the forecast sounding.

NAM forecast sounding for Kansas City (3pm CDT)

NAM forecast sounding for Kansas City (3pm CDT)

Given the above, it’s easy to see why the Storm Prediction Center has kept us in the “marginal risk” for severe weather.  It’s not to say we couldn’t realize a few warnings but there isn’t enough confidence based on forecast conditions to elevate our area into a higher risk category.  We will watch trends through the morning to afternoon and see if the risk increases beyond forecast expectations.

Storm Prediction Center's severe weather outlook today

Storm Prediction Center’s severe weather outlook today

This Morning:  Fairly cloudy with a few sprinkles or a shower possible

This Morning: Fairly cloudy with a few sprinkles or a shower possible

Early Afternoon:  Mostly cloudy, windy and warm.  Isolated sprinkles or a shower

Early Afternoon: Mostly cloudy, windy and warm. Isolated sprinkles or a shower

Late Afternoon - Evening:  Showers or T-Storms

Late Afternoon – Evening: Showers or T-Storms

Evening:  Showers or storms racing east

Evening: Showers or storms racing east

Chris Suchan
Chief Meteorologist
KCTV5/KSMO

Twitter:  @ChrisSuchanKCTV
Twitter:  @KCTV5Weather
Facebook:  https://www.facebook.com/Chief-Meteorologist-Chris-Suchan-361521570703480/?ref=hl

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