Suchan Says: All Eyes on Wednesday

Might as well skip past Tuesday as we’ll all enjoy great weather with intervals of clouds and sun, breezy and mild conditions.  Wednesday is the day to watch as a dynamic area of low pressure ejects out of western Kansas heading toward Iowa during the day dragging a strong cold front to the region.

Every single I chart I review is extremely impressive for severe weather Wednesday.  There is only one key parameter that is very suspect to me and that’s forecast instability.  What I currently see is a strongly sheared environment in which developing updrafts could very well get shredded before they have a chance to tower.

That said, even low-topped storms during the day are capable of very strong wind gusts, some hail and given the strong low to mid level wind field in forecast to be established, a quick spin-up tornado cannot be removed from the forecast.

Instability levels will be held done to some extent from cloudiness through the first half of the day.  By the time this cloudiness begins to dissipate or mix for breaks of sun, the prime window for storms will be quickly advancing out of the area.  So it’s a race against the clock on destabilizing the atmosphere while storms are racing through.

Here’s a forecast sounding for KCI during the prime window…

Analysis of forecast sounding for KCI...  very strong winds through the entire atmospheric column.  Instability in this image is on weaker side.  BRN indice below 10 indicates a very sheared environment (too sheared for supercells)

Analysis of forecast sounding for KCI… very strong winds through the entire atmospheric column. Instability in this image is on weaker side. BRN indice below 10 indicates a very sheared environment (too sheared for supercells)

What I believe may occur, a few very fast moving discrete cells that ultimately form into line segments.  All storms would be moving along at 45mph – 65mph.  Perhaps even a touch faster!!  This forward speed combined with strong winds “just off” the surface would support damaging wind gust potential.

Here are a couple of hour by hour panels showing the prime storm window of 10:00am to 3:00pm in our viewing area…

Wednesday Morning:  Cloudy skies, drizzle or light showers

Wednesday Morning: Cloudy skies, drizzle or light showers

Wednesday Midday:  Still fairly cloudy.  Showers and developing T-Storms

Wednesday Midday: Still fairly cloudy. Showers and developing T-Storms

Wednesday Mid-Afternoon:  Turns partly sunny.  Strong to severe storms moving into eastern counties in our viewing area

Wednesday Mid-Afternoon: Turns partly sunny. Strong to severe storms moving into eastern counties in our viewing area

During the afternoon, we’ll need to closely watch our northern third counties in closer proximity to the surface low and best upper level dynamics from upper low.  Some decent directional shear from backing winds at the surface (South to Southeast wind) into the low will be in place.  This may add a bit more spin to any storms in the northern part of the state to work with.  Additionally, there’s a period in the early afternoon where forecast instability levels briefly spike.

Here are a couple images around 3:00pm highlighting the difference from the KC metro to northern Missouri.

KCI sounding much less supportive of aggressive storms.  Instability rapidly diminishing as dry slot moves over the area

KCI sounding much less supportive of aggressive storms. Instability rapidly diminishing as dry slot moves over the area

Northern Missouri still supportive of severe mid to late afternoon

Northern Missouri still supportive of severe mid to late afternoon

The entire Storm Track 5 weather team will be closely watching this forecast with multiple updates Tuesday on the latest.

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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