Virtual Workshop: Warm Conveyor Belts – a challenge to forecasting
Session
Conveners
Session 1
- David Richardson (ECMWF)
Warm conveyor belts (WCBs) are coherent moist airstreams in extratropical cyclones that ascend from the (oceanic) boundary layer to the upper troposphere. The ascent of typically more than 600 hPa within 1-2 days is accompanied by a strong poleward motion of more than 2000 km, intense cloud formation, latent heating and precipitation. From a dynamical perspective, WCBs are also important...
This talk is largely about butterflies, of the Lorenz variety. In the ECMWF model, Warm Conveyor Belts (WCBs) not only lead to downstream developments such as the formation of blocking, they also act to strongly enhance downstream forecast uncertainty. In this way, WCBs can be thought of as Lorenz-type butterflies on the model's attractor. (A generalisation of the question "Does the flap of a...