Jonathan Weyn

Atmospheric Sciences-Geophysics · University of Washington, Seattle, WA 98195 · Box 351640 ·

Graduate student in Atmospheric Sciences researching theoretical atmospheric predictability and the applications of machine learning to ensemble weather forecasting


Predictability of Deep Convection

Deep convection and severe thunderstorms offer a unique environment for testing the Lorenzian theory of intrinsic weather predictability. Using idealized and real-environment weather simulations, my advisor Dr. Dale Durran and I have made important demonstrations that small errors in model initial conditions on the large scales (e.g., synoptic fronts) have just as much influence as large errors on scales as small as butterflies.

Machine Learning applied to Ensemble Forecasting

Ph.D. Research

A fundamental problem of ensemble weather forecasting is statistical post-processing of ensemble data. How can we determine which of the ensemble solutions will be closest to the observed weather given that all solutions are nominally equally likely? We turn to deep learning to help answer this question, and also apply learning algorithms more generally to weather forecasting.



Weather Forecasting Model

MOS-X is a simple proof-of-concept machine-learning based weather prediction model built using scikit-learn as an improvement over traditional Model Output Statistics (MOS). State-of-the-art numerical weather prediction (NWP) models, such as the Global Forecast System (GFS) and North American Mesoscale (NAM) models, do not represent localized weather well, and therefore rely on MOS to produce forecasts of surface parameters. MOS is an old, multiple-linear-regression technique that has mixed success, so I improved it using random forests and gradient boosting trees. It is currently being entered as a model in the WxChallenge and competes well with human forecasters!

Weather Station Website

Since October 2015 I have managed a personal weather station reporting weather at the University of Washington's Atmospheric Sciences-Geophysics building. The data are displayed on my weather station's website here.


Machine Learning tools for Ensemble Forecasting

To address my second topic of research above, I am developing code to analyze weather model data from the NCAR operational ensemble forecasts and calculate verification metrics from observed radar and surface data. This work-in-progress will ultimately be a generalized tool to build AI models to predict many weather parameters from these datasets.


Forecast Verification Tools

With so many different sources of weather forecasts out there (National Weather Service, Weather Channel, AccuWeather, to name a few) how do we know which one is most accurate? And, supposing you're an amateur weather forecaster, how do you put all that data together into a better forecast for tomorrow's weather? That's what theta-e is built for.


Durran, D. R., & Weyn, J. A. (2016). Thunderstorms Do Not Get Butterflies. Bulletin of the American Meteorological Society, 97(2), 237–243. DOI

Weyn, J. A., & Durran, D. R. (2017). The dependence of the predictability of mesoscale convective systems on the horizontal scale and amplitude of initial errors in idealized simulations. Journal of the Atmospheric Sciences, 74(7), 2191–2210. DOI

Durran, D., Weyn, J. A., & Menchaca, M. Q. (2017). Practical Considerations for Computing Dimensional Spectra from Gridded Data. Monthly Weather Review, 145(9), 3901–3910. DOI

Weyn, J. A., & Durran, D. R. (2018). Ensemble spread grows more rapidly in higher-resolution simulations of deep convection. Journal of the Atmospheric Sciences, 75(10), 3331-3345. DOI

Weyn, J. A., & Durran, D. R. (2018). The scale dependence of initial-condition sensitivities in simulations of convective systems over the Southeastern US. Quarterly Journal of the Royal Meteorological Society. DOI


University of Texas at Austin

Bachelor of Science
August 2010 - May 2014

University of Washington

Master of Science and Ph. D.
Atmospheric Sciences
July 2014 - present