Severe Weather Bust?

If you've been up for long and peaked at the radar, you'll see that not much is going on across our area. Remember, at this point, I was expecting storms to be ongoing across our Mississippi Delta counties. I was also expecting that southwest Mississippi would remain mostly storm-free due to warmer temperatures aloft preventing storms from becoming organized. This warmer air aloft is called a "cap" and it helps to stabilize the atmosphere. This is why we had no storms over our area yesterday (which was expected). It is also why my forecast was for only isolated severe storms along the I-20 corridor, versus a more scattered nature to the severe storms, like they are seeing further north.

Data from the weather balloon launched by the Jackson National Weather Service at 6am this morning shows that the warmer temperatures above the ground (the cap) have been stubborn to weaken. In fact, they are actually warmer than forecast by the models. This is why storms have not been able to develop across the Delta counties, despite the presence of the frontal boundary nearing that area. Essentially the front is not strong enough to overcome that layer of warmer air aloft, so any storms that try to develop get quashed.

Satellite imagery shows some breaks in the clouds this morning and this MAY allow for storms to develop further south along the front by late morning and into this afternoon as we'll then have the combination of the front (providing "lift") and daytime heating (providing more instability). The combination of the two MAY be enough to overcome this cap, especially if it weakens as model data suggests. But, again, models over estimated the strength of the cap this morning, so it isn't etched in stone that they've not done the same thing for this afternoon.

If, in fact, we are able to see storms form further south in Mississippi, it will probably be after the front has cleared the western parts of the area. So, most areas west of the I-55 corridor may actually miss out in seeing any rain today. Also, as the main storm system will be pulling away from us later this morning, winds will become less favorable for tornadic development, so if storms do get going along the front later today, the severe threat will be confined to damaging straight-line winds and large hail, so that part of my forecast remains in place.

So, to answer the question raised in this blog post's title, "Is it a severe weather bust?" It certainly is for the Delta counties. I underestimated the strength and duration of the cap there. The forecast has panned out for southwest Mississippi, where I really did not expect much in the way of rain or storms due to the cap being stronger in that part of the state and the fact the main storm system was well north of that area. I still think isolated severe weather will be possible along and east of the I-55 corridor, so that forecast is not a bust...yet. The atmosphere is loaded and ready to go, so if the cap is broken, storms will form and they will become severe with strong winds and hail being the primary threat. If the cap is not broken, it will just be a breezy, warm day.

The Jackson National Weather Service will likely release another weather balloon later this morning (still awaiting on a decision as to whether it will be 9am or 12pm). Just heard from the weather service they will send up another weather balloon at 10am. Should have some early data by 10:15-10:30am. That data will be able to tell us how the atmosphere is shaping up. Follow me on Twitter for updates as things develop the rest of the day.

Eric - elaw@wlbt.com