Joe’s Wx Blog: Weekend Storm Chances

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A bright and beautiful day around the region today with clear blue skies and just a few clouds out there. Temperatures are now around 70° and we should go up another 5° this afternoon. Off to our west we’re starting to see the genesis of clouds and even a couple of T/showers across parts of KS/NE. Here is the satellite picture this afternoon showing the clouds to the west of the region.

 

From a radar standpoint there are a few showers developing. Here is the radar from Grand Island, NE showing the developing convection.

 

I choose to use this radar as it might be the one to help us nowcast the weather over the weekend. The flow aloft, up at around 18,000 feet features a nice Midwest ridge. The ridge though is not the strongest and the storm across the northwestern part of the country will be sending out weak waves that will interact with warmth and moisture in the Plains states allowing convection to form closer to home, especially to the NW of the KC area.

 

These disturbances as they come out of the trof affecting the western part of the country, should help to flare off storms in the PM hours to the NW/W of E KS-W MO. From there though it will get a bit tricky in figuring out where the storms will go and how long they will live. Typically when storms form that far to the west they mainly affect our area late at night or early the following day. The other issue is that these storms may also create various outflow boundaries that may create additional storm activity in the afternoon on a scattered basis.

So what does all this mean for the weekend forecast? It means at some point there will be storms on radar. The highest chances right now look to be tomorrow morning through early afternoon and then again sometime during the 1st part of the day on Monday. That’s not to say Sunday will be perfectly dry but it looks to me that Sunday has the lessor chances.

Our model data will have a struggle with these types of situations, the waves may exist, but the storms from said waves don’t exist. For guidance purposes here is a look at the hi-res NAM model showing one of these clusters of storms moving our way 1st thing Saturday AM.

ScreenHunter_06 May. 24 13.39

The above image is valid for 7AM. Now should the cluster of storms NOT develop tonight across W KS and instead develop more towards the north or NE, then we could miss out on most of this activity in the AM tomorrow. There is a lot of dry surface air moving through W MO right now and moving to the NW thanks to SE winds…so IF anything makes it here it will be sucking in said dry air and should weaken as it does so.

Here is what I’m talking about…take a look at the surface map showing where, at least right now, the best moisture is moving from and to.

sfc

Here is a look at the 500 mb forecast into the weekend. Can you see the little red blobs? They’re small but certainly there. The models though will moves these little “blobs” all over the place with each run…so that’s why you have to just take things as they develop and figure out where they’ll go from there.

 

So a lot may happen over the next 3 days…and again rain is likely at some point…main timing would be one chance tomorrow AM, with another later Sunday night into Monday (maybe the heavier round).

There have been some interesting things coming from the weather data with regards to the Moore tornado. 1) this image showing the radar from the 3 different big tornadoes that have affected Moore over the last 15 years…

 

The tell-tale “hook” echo is clearly seen on the images above. 1999 was a F5 tornado. 2003 was a F4 tornado and 2013 was obviously an EF5 tornado.

Meanwhile here is some great video showing the life cycle of the Moore tornado from Justin Cox and Chance Coldiron

Also this is a neat, though tragic map(s) showing the destruction in before and after satellite pictures. Take a look and use the slider bar to see the “after” look.

Joe

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