Severe Weather Potential for the End of the Week
So what's going on? Currently there is a cold front moving very slowly over the Great Lakes Region, and that will stall out over parts of West Virginia on Thursday. Then that system moves through Friday night.
With at least plenty of sun for the first half of the day on Thursday, that will help de-stabilize the atmosphere for some scattered storms Thursday afternoon and evening. Anyone has a chance at seeing these storms so we can't say, a certain town will see a storm at 5pm. Thunderstorms don't exactly work on a schedule like that. Best chance is after lunch, probably after 2pm until later Thursday evening. I heard this analogy while I was in school and I think it's a great explanation of how unpredictable pinpointing where a thunderstorm will fire up. Think of a pot of boiling water, you know there's going to be boiling bubbles. But try to figure out where that first bubble will pop, or the second bubble. Trying to pinpoint thunderstorm formation is like that. We know the ingredients are there. But we can't say where they decide to fire up.
Here is a look at the risk from the Storm Prediction Center for Thursday.
We are out of the greatest threat area but still a 5% chance of seeing severe storms.
While that doesn't sound likely, that does mean that there is a chance for a few of the storms that develop to become severe.
By severe that means winds over 58 mph or hail larger than a quarter.
Since this front is going to be so slow moving, and there's already a pretty humid air-mass in place, there's going to be A LOT of available moisture.That means there could also be a flash flooding potential. (We talked about how we know sometimes storms could be slow movers in our Weather Questions segment on Monday night, for that info click on the previous blog).
As that front moves in a bit closer on Friday, that's when things could really start to get going and there's more widespread storm potential for Friday.
Here is the outlook from the Storm Prediction Center for Friday.
Right now we're in a 15% chance of severe storms, and yes I believe this shaded area could change and be updated.
We do have a few things working though, to limit the severe potential.
Cloud cover: We should have plenty of clouds of Friday, that will help limit the instability.
Remember, the more sunshine, the more warm air is able to rise, and the more unstable things become.
Shear: Or shall I say, lack of shear. Wind shear, or changing of wind direction and increasing wind speed with height is needed for organized storm cells. There will not be much wind shear on Friday, or direction shear. That is, not much wind direction change with height. There are going to be some strong upper level winds though.
This is a picture from a forecast model, the NAM of Friday at 21Z which is 5pm. I know it may be a bit hard to read though.
You can see the estimated precip on the right but notice where I have the arrow drawn in the center, and the pink shading.
The pink indicates stronger upper level winds, at about 10,000 ft up in the atmosphere. Those strong winds can be transported down to the surface within a thunderstorm downdraft.
Biggest threat? Damaging winds and large hail and even flash flooding potential once again.
On the flip side, how about temperatures in the upper 70s and low 80s for the weekend! That's fall-like weather for the middle of August! Enjoy while you can because I'm sure the heat will return soon.
As always we'll have the latest as we get closer into Friday. Always a good idea to have text alerts so you know when there is a severe weather alert for your area. Should the risk increase then we would declare a Severe Weather Alert Day.