A severe weather risk has been posted for Friday, but the forecast is a bit more complicated than that. 

Almost all of our WDRB counties are included in this Slight Risk of severe weather Friday, but some storms could carry over into Saturday, too.

The main threats (as of Wednesday afternoon) are damaging wind, hail, and isolated tornadoes. The wind threat is the main one. As this system comes together, those threats could change. 

With an upper-level low pressure near the area for most of the weekend, a cold front passes through Kentuckiana early Saturday morning sparking this storm chance. 

We will feel the impacts of the leading warm front early Friday with more storms coming late, so plan for a couple different waves of rain. The greatest chance for strong/severe storms will be late Friday, as you'll see from the ingredients below. 

INGREDIENTS

There is a very weak low level jet present Friday night over our area which is part of the reason the wind threat is our main concern. Normally this would need to be 40-50+ to be a big contributor to severe weather. 

An interesting element in this forecast is the strong positive vorticity nearby thanks to the upper-level low and how that is moving (advection).  This will create rising motion and some spin in the atmosphere which is why we have included the small threat of isolated tornadoes. 

Instability - a measure of storm energy present in the atmosphere - will be very high during the afternoon. These numbers seem a little inflated, but 2500 CAPE seems a very safe bet across all models Friday afternoon. It's interesting that CAPE stays high in may spots through Kentuckiana after midnight (part of the reason we are emphasizing that this threat continues into Saturday morning).


TIMING

There is a Friday morning chance for isolated storms.  If these become strong, it would help stabilize the environment to prevent stronger storms later in the day. If this early round comes later in the morning, the atmosphere won't have as much time to recover by the later round which would keep it from getting as strong. 

The late night chance is the one that looks strongest, but the strength depends on what happens during the morning. Watch for more updates from us here on the WDRB Weather Blog and during WDRB News on TV.

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-Hannah Strong

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