4 June 2014
If a thunderstorm has an extremely strong updraft it will push all the way into the stratosphere before weakening. The air actually starts to get warmer in the stratosphere, and a warm bubble of rising air suddenly finds itself colder than the air around it, and will eventually sink back down. So, the higher the updraft penetrates, the stronger it must be. This is why meteorologists are keen to know which storms have these overshooting tops, because they are highly correlated with severe weather of all types.
We can see them in the daytime on high res. visible images, but infrared images at night have less resolution and make it difficult. One of the products we are evaluating at the Hazardous Weather Test Bed this week is an algorithm that detects these tops. When the new GOES R weather satellite launches in two years, it will have a much more advanced instrument (with much higher resolution) and it should be able to detect them much better.
For now we are using the present 4km IR resolution to evaluate the usefulness of this product to forecasters. The image above is what I was looking at today, and the red dots are overshooting tops. As you can see, there were a lot of them, and large hail and wind gusts over 70 mph were reported across Nebraska. Late this evening a tornado was also reported near Grand Isle.
We are also evaluating a product called the Probability of Severe which uses high-resolution numerical weather models, along with radar,satellite data to predict how likely a storm is to produce severe weather. I have found this product very useful and another algorithm uses satellite data to point out rising cumulus towers that are about to become thunderstorms.
You can look at the current runs of the RAP model used in the algorithm here: http://rapidrefresh.noaa.gov/RAP/
If you’re a student who is interested in studying atmospheric science, I hope this gives you a bit of an introduction to what is happening in the field. If you look at the model data you will understand why my advice to you is to take all the math and physics you can in high school, but don’t let it scare you! It will open up a whole magical world for you!
If you’re just a taxpayer like me, you should know that very smart researchers and forecasters are working really hard to give you advanced warning of dangerous weather, and to improve short-term forecasts that might some day mean the difference between life and death.