Potential for Severe Storms Friday

Good afternoon, hope everyone is having a nice Wednesday afternoon.  The warm conditions continue for Central Indiana with temperatures in the upper 50s to mid 60s with cloud cover still around, but beginning to break up some.  feb-22-2017-1343

However the focus of this blog will be on the potential for severe weather on Friday.  The Storm Prediction Center has placed all of Central Indiana under an “Enhanced” risk of severe storms on Friday.  slide15

Now when it comes to severe storm potential, there are a few things that I look at in determining overall risk.  At the surface, an deepening area of low pressure that by 7 am Friday morning will be centered over South-Central Iowa and North-Central Missouri, with a trailing cold front sagging southward across Missouri and points south.  slide22

By the early afternoon hours, low pressure will be over southeast Iowa with a warm, moist southwest flow ahead of the cold front.  It will be breezy, with winds at times gusting over 30 mph.  slide23

By Friday evening, area of low pressure will be over Northern Illinois, with cold front approaching the Indiana border.  Winds at 18,000 feet will begin around 60 to 75 kts at 7 am Friday, and increase dramatically to over 100 kts by 7 pm Friday evening.

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Another thing that we will need to concern ourselves with is cloud cover.   What we want to see in these types of severe weather events, is cloud cover to keep surface heating to a minimum.  Right now unfortunately, it seems that we could see several hours of sunshine and as the models suggest, highs could reach in the low to possibly mid 70s, with that, there will be plenty of instability to feed these storms.  Of note, the record high in Indianapolis on Friday is 71 degrees, set in 2000.

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Another thing that I look at behind the scenes is the Convective Available Potential Energy, or CAPE for short.  This is one of many indicators of instability in the atmosphere.  The higher the number, the higher the instability.  Above, we mentioned several hours of solid sun and decent surface heating could lead to higher instability, well this shows very well what surface heating can produce.  For February, these readings are on the high side and more than sufficient enough to create severe thunderstorms.

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So putting everything together, here’s how the radar could look like from 7 am Friday to 1 am Saturday.  There could be a few isolated showers Friday morning, but for now much of the day should remain dry.  As we head into the early afternoon hours, showers and thunderstorms should begin to develop, there could be a few supercell storms that could produce anything from large hail, to isolated tornadoes.  Thunderstorms should congeal to an intense squall line that could produce damaging winds.  Severe threat should wind down by late in the evening hours.

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To sum everything up, we do have the potential of seeing strong to severe storms on Friday.  It looks like the timing of severe storms will be from 4 pm to 11 pm.  All modes of severe weather are in play based off the latest data, with damaging winds however being the highest risk.  Large hail and isolated tornadoes are possible IF thunderstorms can form ahead of the main line of storms.  A lot can change between now and Friday, so the best thing to do is keep an eye for additional updates.  We will update the blog again either Thursday morning or Thursday afternoon.  Remain weather aware!

Potential threats with severe storms on Friday afternoon and evening for Central Indiana.