A big trough with lots of energy will roll over the Plains this weekend, bringing stormy weather to many. The severe weather risk with this system does look to be limited due to warm temps aloft suppressing storms initially and then overwhelming forcing leading to numerous storms which will limit instability and thus, severe weather chances.

But many of us will get rain!

A strong dryline to take shape on Sunday, but warm temperatures aloft and forcing located way west of the dryline will limit storm development.

On Sunday, the bulk of the upper level forcing will be located well north and west of the dryline. For dryline setups, unless there is only a little capping you really need upper support to get storms to fire.

The Rainy Period Begins Monday

But the upper support does arrive by Monday — morning. The timing of the upper level wave on Monday, and the amount of forcing it is bringing will lead to widespread showers and storms.

A look at the overwhelming amount of forcing coming out on Monday. On a 500mb vorticity map like this, you know there’s lots of forcing arriving generally when there are bright/warm colors everywhere.

 

It is likely that a strongly forced line/band of storms will move east through the region on Monday. There will be a low severe weather risk anywhere pockets of surface-based instability can take shape.

Limited Instability

The lack of instability will be very notable throughout this event. The strong moisture advection into the region will lead to widespread low clouds in the warm-sector, which when combined with ample clouds higher as well will lead to very limited instability values.

The situation along the dryline on Sunday is pretty dire, with very limited instability due to a warm thermal profile.

Monday will have a different set of problems, with widespread clouds overspreading the warm-sector leading to nearly non-existent surface based instability through the day.

A day that might need to be watched for a pocket of enhanced severe weather potential is Sunday along the Gulf Coast. Really strong wind shear may combine with weak instability for a reasonable severe weather risk.

But the Rainfall Totals!

The rainfall totals from this system are going to be measured in the inches for many in the region. As we head into a La Niña winter, you want every last drop of rain you can get to stave off the worst drought conditions. While not every La Niña winter ends up in drought, most do. So this system will be a nice one to get as we roll into the cold season.

Seven day rainfall forecast from the Weather Prediction Center (WPC).

Up Next?

We will have another system rolling through the Southern Plains on the 28-29 or so it looks, but instability will likely be limited with that one as well.