It has been a very soggy and stormy week for most of the eastern half of the U.S. and there is still more to come. We have been “stuck” in a weather pattern this week but luckily we will be “unstuck” just in time for the weekend.
Why are we “stuck”? It all has to do with the jet stream. The jet stream is an area of fast moving winds in the upper atmosphere that tends to steer our weather patterns in the U.S. Big dips in the jet stream tend to bring in colder air. High ridges in the jet tend to bring in warmer air. Big shifts in the jet stream take time, sometimes days to transfer from big ridge to trough. This week, an upper level area of low pressure has been stuck in a trough in the jet stream over the central U.S.
On the surface, a big cold front stretches from the Great Lakes to the Gulf of Mexico. Because the jet stream has been slow to shift, the front has been very slowly sliding east. Warm, moist air and instability has been streaming in ahead of the front prompting the severe storms.
The general set-up remains the same for today… big cold front to our west, unsettled weather expected for much of the southeast. You may have noticed a few changes so far this morning… warmer, more humid, maybe a glimpse or two of sunshine. While on a “normal” day these may be nice to see, today these may spell bad news.
I always like to compare severe weather to baking in the kitchen. In order to have storms, you have to have all of the ingredients; moisture, Instability, and lift. Just like in the kitchen, the more ingredients you have the more cakes you can bake. Today’s warmer air, humidity, and glimpses of sun are adding more “ingredients” to our atmosphere. However, just like in the kitchen, more ingredients do not guarantee more cakes but it makes it possible.
Expect storms to “fire up” this afternoon across the Southeast. Heavy rain, potential flash flooding, wind gusts, hail, and tornadoes are all possible.
The cold front will finally push off of the East Coast tomorrow night as the upper low and trough finally lift north and break down. What does that mean for our forecast? Lower rain/storm chances and more sunshine… just in time for the weekend!
-Meteorologist Myles Henderson