Changing Threat of Severe Weather

day1otlk_1300 Earlier we talked about strong, damaging winds as the primary threat with today and tomorrow’s severe risk.  Slowly but surely that’s beginning to change… at least for today.

The Storm Prediction Center in Norman, OK has scaled back the slight risk for today, pushing it back to just the western half of Iowa.  This morning it appears storms will have a difficult time reaching severe limits until late afternoon or early evening.

day1probotlk_1300_hail Those storms should eventually produce supercells with the primary threats of large hail and isolated tornadoes.  But storm motions are not expected to be what we thought 24 hours ago.  

day1probotlk_1300_windWhat this means is a lesser chance of bowing lines and strong winds racing across the state.  You can see in the graphic to the left the wind threat is much lower than the hail threat you see to the right.

Now this doesn’t mean the overall threat for severe weather is lower.  It just means the primary threat has shifted somewhat to large hail.  The other change (and the reason for the slight risk pushed back west of I-35), is that storms are no longer expected to hold their intensity through the overnight hours.  This change also limits the threat of a widespread wind event tonight. 

day2otlk_0600 Now for Friday.  What happens tonight will obviously greatly influence the setup tomorrow.  The eastern half of Iowa remains in the threatened area, with a primary threat over the eastern third of the state.  All modes of severe weather are possible in Iowa.  With storms developing somewhere east of I-35, this area is primed for tornadic development.

day2probotlk_0600_any With an advancing cold front I don’t expect the tornado threat to last very long before shifting to a strong wind event.  This is something we’ll have to monitor because straight line winds often affect a much larger area.  Either way storms should push out of the state relatively quickly as the cold front tries to clear things out.

We’ll take a closer look at tomorrow’s risk later this afternoon before we begin more regular updates on today’s severe weather threat for western and central Iowa.

Showers and thunderstorms remain a possibility this weekend, but at this time, the severe weather is expected to remain to our south and east. 

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