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Weather Blog: Wind Shear: A Contradiction

Today's weather blog discusses the topic of Wind Shear, and how it can both promote and hinder development of storm systems. Wind Shear will play a factor ...

So I was typing yesterday’s blog and to say I was struggling is a drastic understatement. While I was typing yesterday’s blog I got the perfect idea for today’s blog. I’ll go ahead and warn you now, and say that this blog will be one of those Meteorology 101 blogs. At this point I know you’re well aware of the developing area of low pressure just off the coast of Central America in the Gulf of Mexico. It’s been the hot topic of discussion because it could bring a fair amount of rain to the southeast come this weekend. This weekend just so happens to be Jubilee weekend and Memorial Day Weekend.

As I was looking things over and typing yesterday’s blog I realized I was giving you somewhat of a contradiction. You see the three main ingredients for severe weather are wind shear, moisture, and instability. The three ingredients can create quite the active weather day. Wind shear will be the focus here. While wind shear helps in the formation of severe weather, it actually hurts in the formation of tropical weather. Doesn’t make a whole lot of sense right? That’s the topic of today’s blog.

In terms of severe weather the wind shear aloft helps to chop off the top of a thunderstorm forcing it to tilt. This furthers the development of severe thunderstorms because the strong shear allows the updraft to be separated from the downdraft allowing the storm to survive longer. When the storm tilts we can see further development into super-cells that rotate and therefor tornadoes. The exact opposite occurs in the tropics. 

In terms of tropical development the more upright the storm the better. In it’s most basic terms, hurricanes develop from an initial surface low allowing the heat and moisture to be sucked up into the low allowing the low to grow in height and strengthen. Once it reaches it’s maximum height it begins to spread and that’s how the eye and rain bands form in a hurricane. If you have strong wind shear aloft the storm gets chopped off the same way it does in a severe weather setup, but this time it hinders development because the eye is never able to form because the low can’t strengthen to it’s maximum potential because the wind shear is chopping the top of the storm off and tilting the storm. Again in order for the eye to form the storm must remain upright. That semester of tropical meteorology I took is really paying off right now, thanks Dr. Dyer. 

Thinking about where we’re at currently we have this area of low pressure that’s rather disorganized still sitting in-between Central America and Cuba. In time this low will push north into the Gulf Of Mexico. Notice the percents though. This low has a 0% chance of further development over the next two days, but a 50% chance over the next five. Why? Wind shear. 

Wind shear is the sole thing keeping this storm for strengthening further in the immediate future. In the upper levels there is a strong jet bringing winds out of the west. It’s those winds that will chop the top off this area of low pressure preventing it from taking on any tropical characteristics as it moves north.

Once it does get into the central Gulf of Mexico, it’ll be in an environment with warmer waters and far less wind shear. For that reason, we will see some strengthening of this low. It’ll be sloppy and disorganized through Friday bringing scattered showers but as we get into Saturday and the second half of the weekend, rain could become more widespread. Heavy rain will be the theme and flooding will likely become a large concern along the coast. 

With that we conclude today’s lesson of Meteorology 101.