Good morning bloggers,

At the end of March the pattern that was extremely dry with a growing drought suddenly turned wet across the plains.  This trend has continued and I hope it will last the rest of spring, but I still doubt it.  I am expecting the first half of May to have way below average rainfall, but not the last dozen days of April.

Forecast for the next month in Kansas City:

  • Last half of April: A series of storm systems with near to above average rainfall with near average temperatures.
  • First half of May:  Above average temperatures with below average rainfall

We will likely add to the surplus of rain that developed since spring began. May is one of our wettest months and even though that first half of May does look dry in my analysis, the second half of May could make up for it.

The Arctic Oscillation finally dips negative:

As this pattern began setting up last fall there was a lot of talk about it being an AO negative winter. It ended up being more of an AO positive winter and is likely one of the biggest reasons for the warmer than average temperatures in most of the United States.  In the past few days the Arctic Oscillation has dipped negative and it is forecast to stay a bit on the low side for another week or so.  We are moving into the part of the pattern that produced the Christmas storm system. That storm dug into the west and then lifted northwest of Kansas City producing some severe weather and thunderstorms. That part of the pattern is now cycling back through this week and the weekend storm can be traced to that Christmas storm system.

Huge Model Differences On The Rainfall Forecast

There is a huge difference between the European Model forecast for this weeks rainfall amounts and the GFS model output. Here are the two extremes:

This map above is the latest European model forecast. This model shows the upper level storm going through a transition and turning southeast. The GFS has a much more mature storm system that produces a very different output as you can see below.

At the Chillicothe, MO location it is a difference from 0.08″ to over 2.00″. We will be monitoring these developments closely.

The set up for the next two days:

Last night on the air I ruled out the thunderstorm potential for Tuesday, and the models are coming in with weak forcing and almost no thunderstorm development as of 9 PM tonight as you can see below:

By Wednesday conditions become a bit more favorable for severe thunderstorms. Storm chasers know well to look for where the surface  low is going to track, and where the other convergence zones are located. A convergence zone is a front or trough where the winds converge together. Let’s look for them on Wednesday evenings forecast map from the NAM model below:

The tropical point can be argued to be near that eastern Iowa low pressure area. Another low is forecast to develop over the northeastern Texas Panhandle. It is always just so difficult to forecast severe thunderstorms, especially when there is not even one radar echo as capping comes into the equation. There will be a cap today and tomorrow. I circled the most likely area to have severe thunderstorms tomorrow, but we still have to monitor central Kansas and where that front is located.  The models have the thunderstorms that do form dissipating before they get to Kansas City around 10 PM Wednesday night.

We will then move on to the weekend storm system. More on this one in the next few days.  Have a great Tuesday! We had a great event on Saturday. Here is a picture of our storm chasers and our weather team with Sunny. Jeff Penner had left a few minutes earlier.

Gary