Virtual Workshop: Warm Conveyor Belts – a challenge to forecasting

Weather regimes are quasi-stationary, persistent, and recurrent states of the large-scale extratropical circulation. In the Atlantic-European region these explain most of the atmospheric variability on sub-seasonal time scales. However, current numerical weather prediction (NWP) systems struggle in correctly predicting weather regime life cycles. Latent heat release in ascending air streams...

The examination of model error is fundamental to improve weather forecasts at any time scale. In this contribution, model error in potential temperature and potential vorticity (PV) is analysed through the examination of 12-h and 24-h forecasts at the grid-point level using an Eulerian approach and another based on the use of diabatic tracers of potential temperature and PV. Diabatic tracers...

Atmospheric waveguides denote the location of the jet stream and constrain the motion of Rossby waves. Perturbations of the waveguide, such as those associated with the warm conveyor belt (WCB) of midlatitude cyclones, can lead to the downstream radiation of Rossby waves, which can often spawn high-impact extreme weather events. Previous studies have hypothesized that forecast errors...