© 2019 Terry Swails

SOBERING RAIN PROSPECTS...

May 17, 2019

You know its been a storm free spring when going into May 17th none of my area has been under a tornado watch. The first thunderstorm watch finally came Thursday evening with a barrage of storms that pounded my southern counties. Until then all the action had been across the south. Here's the tornado watches that have been issued in 2019.

Now the thunderstorm watches not including the one issued Wednesday for my area.

Below you can see how 2019 (through May 14th) is squarely at the bottom of the list when compared to severe thunderstorm and tornado warnings going back to 2008. Its been quiet as a mouse.

The primary reason for the absence of storms in the Midwest has been the lack of heat and moisture to generate instability. This is a remarkable statistic. Until Wednesday in Des Moines, there had been only 2 hours with dew points above 60. The average is 44!  

Well, we clearly broke the ice on heat and humidity with our high of 90 and dew point of 66 Wednesday afternoon. The instability set the table for the first widespread round of storms, just the beginning of an active period that will last on and off again for at least the next 10 days. 

 

One of the biggest challenges from a forecasting perspective in the days ahead will be predicting temperatures. On Friday a lake enhanced front will cut near or south of I-80 creating a 25 degree spread in readings from north to south. Those 90 degree temperatures will be long gone from my area, especially north of I-80 where 50s and 60s will prevail. That front is going to vacillate north and south through next week allowing temperatures to ping pong. Unfortunately, my region will remain on the cooler side of the front for the bulk of the period.

 

Again, the biggest concern for me is the persistence of the pattern. Showers and storms are going to be regular visitors and the potential is high for excessive rainfall. The latest GFS has this for rain out to May 30th. If this verifies there are going to be all kinds of flooding issues by the end of May.

In fact, the NWS has already expressed concerns about renewed rises on the Mississippi and its tributaries. Most places along the river in my area are again expected to reach moderate to major flood stage by the 23rd with the rises beginning by Sunday. In the Quad Cities at LD 15 the river is shown reaching 18-20 feet. That does not include the type of excessive rain the GFS shows above. Hopefully it is off base but its been consistent showing this type of scenario.

 Well, I'm burned out after 3 hours of warnings and I'm going to wrap this up. Thank God its Friday! Roll weather...TS

 

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