We’ve had an interesting set of events occur recently which makes me really wonder just how much severe weather we are looking at next week.
Is there a chance for storms? Yes. Is there a chance storms turn severe? Also yes. Is there a giant asterisk to the forecast. Definitely yes.
Let’s walk through it all….
The Setup
A pretty stout area of low pressure will slide out into the Plains from the Rockies Monday (left, below). The Low will slide to the northeast, and will interact – loosely – with a ridge of higher pressure down into the Gulf. As the low slides by it should do enough to open up the atmosphere aloft for showers and storms to develop along a cold front that should pus across the Gulf Coast states early next week.
Down at 850mb, in reaction to the placement of the Low and High up at 500mb, there will be a surge of Gulf of Mexico moisture into the region. This will be pretty juicy air. And that will further help to spark off showers and storms along the cold front and will also help to amplify the severe weather threat along the front is it passes through.
The Forecast
The Storm Prediction Center shows an Enhanced Risk for severe weather across mainly Arkansas and Louisiana on Monday and a Slight Risk in a larger area. Then the SPC shows a Slight Right for severe weather across Mississippi and Alabama on Tuesday.
The forecast for Tuesday is supported by the CIPS Analogs data. Recall how CIPS Analogs works – it looks at the atmospheric setup and the compares it to past severe weather events and fins if this upcoming setup matches any big severe weather days. It then uses that information and lets the computer make an assessment as to what the chance for severe weather could be.
The CIPS data is showing a greater than 30-percent chance for severe weather across southeastern Mississippi and southwestern Alabama on Tuesday. The data also shows a 15-percent chance for , at least, one tornado.
The areas shown with the highest risk above are likely going to change in the coming days as we get closer and better data comes down. But the trend is showing a greater risk for severe weather across southeastern Louisiana, southern Mississippi, and Lower Alabama.
The Asterisk
The ability to transfer heat from the Caribbean and Gulf inland is generally dependent on the sea surface temperatures of the Gulf of Mexico. The warmer the water, the easier it is to move warm air from the Caribbean inland. The cooler the water, the more difficult it is to do. Because the warm air is modified by the cooler water.
The surface temperatures of the Gulf along the shelf is currently pretty cold
Looking at the comparison in sea surface temperatures right along the coastline two weeks ago to the temperatures in the same area today. And the general warmth of the Gulf is down slightly, too.
This may do two things. Firstly, this will help to limit just how much heat is advected into the region from the Caribbean.
The secondary effect may be similar to what we saw happen today. A big line of storms comes barreling through but because the Gulf is cooler, the Marine Layer of air is also cooler, and it can help to undercut the storms and limit how much warm air they have to ‘eat’ and it limits just how severe those storms can be.
That said. Looking back at two big tornado days in the region the Gulf is ‘generally’ warmer today than it was for those two events.
So, it isn’t like this is a slam dunk. Sadly, we may have to wait-and-see for a few more days.
The Bottom Line
The forecast is going to change a bit in the coming days. But , given the latest data, I think there is enough evidence to support a risk for severe weather across the region on Tuesday. The threat for storms on Monday should stay northwest of the Southern MS/AL/LA area.
So, Tuesday is our day for storms.
The risk for severe weather isn’t a slam dunk. I tend to think that the shelf waters of the Gulf may play a factor in just how much severe weather we see closer to the Gulf. Also of note: I think places north of I-20 will be unaffected by the Gulf of Mexico water temperature discussion.
You are probably starting to get the feeling that this is going to be one of those events where there are a lot of moving parts – and you are not wrong.
For now, this is a wait-and-see situation for specifics. But what we do know is that the atmospheric setup is one that, historically, produces severe weather. And so it bears monitoring.
