MOBILE, Ala. (WKRG) — Many of you are probably wondering why we did not see tornadoes in our area this past Saturday. Meteorologist Caroline Carithers spoke with Meteorologist in Charge Jeff Medlin at the National Weather Service (NWS) in Mobile since the forecasters at NWS are the ones that issue the warnings.
Remember that severe thunderstorms have THREE criteria. We only need one of them to be occurring to have severe weather. In order for the NWS to issue a severe thunderstorm warning, the storm has to have wind gusts of 58 mph or more, 1-inch hail OR a tornado. Severe weather is not just tornadoes.
That being said, Jeff Medlin also talks about how all of the ingredients were there for tornado formation on Saturday. These ingredients are wind shear (change of wind direction or speed with height) and instability. However, when the system rolled in, we ended up have too much of one ingredient – wind shear.
Medlin explains, “If you can just imagine taking a garden hose with water flowing out of it, if the wind is blowing, it will quickly blow the water downstream versus if the winds were lighter, it would go straight up. That is literally what was happening to the knees of the updraft on Saturday. The winds were just too strong.” The updraft (rising air) mentioned is the water in this analogy. For tornadoes to form, the updraft has to stretch straight up. If the winds are too strong and prevent this from happening (what happened Saturday), this prohibits tornadoes from forming.
Medlin also explains that close to the surface (the winds mentioned), models do not resolve processes well. This is why we have meteorologists.
All in all, the Storm Prediction Center did a great job with the outlooks on this event. More than 5 days out, they had an area outlined with 30 percent chance of severe weather. Many in our area did see severe weather, just in the form of damaging wind gusts. Remember, this also means that there is a 70 percent you will not see this severe threat.
Ultimately, we are lucky that our area did not see tornadoes. Others were not as fortunate. This system claimed the lives of ten people and our hearts go out to them, as well as people in our area whose homes and property were damaged from the wind gusts.
Check out the video for more!