The Relationship Between Severe Storms and Weather Regimes Over the US

Megan Biesmann, “The Relationship Between Severe Storms and Weather Regimes Over the US”
Mentor: Paul Roebber, Mathematical Sciences

Weather regimes are wind flow patterns that cover a large region, approximately the size of the continental United States, and they change over days and weeks as the wind flow patterns change. They affect local weather in different ways depending on what the flow is. It is unknown if small-scale weather, like thunderstorms, influences these changes in weather regimes. Using a National Oceanic and Atmospheric Administration (NOAA) database, we created a gridded analysis over North America to analyze the wind flow patterns and identify weather regimes using a technique called cluster analysis. The study will continue by investigating if regimes (flow pattern clusters) or if certain transitions between regimes indicate specific types of severe weather. Bootstrap analysis, a technique used to determine if differences have a statistical significance, will be used to ensure that any differences found between clusters and transition between clusters are significant. In particular, transitions between regimes that can be associated with thunderstorm activity would suggest the aforementioned upscale effects on regimes. The conclusions to this project are unknown, but if an effect on weather regimes is found, it could help to improve long-term forecasting.

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link to full poster


  1. Very nicely done, Megan! I look forward to seeing what you are able to discover as you continue this project over the next couple of years!

  2. What an interesting and visually appealing poster! It will be interesting to see these results!

    I didn’t quite understand the significance of the 500mb threshold, and would have liked to understand that a bit more. Also, what kinds of weather was considered severe?

    Overall, great work!

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