Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.
Section
Column

Introduction

In these exercises we will look at a case study of a severe storm using a forecast ensemble. During the course of the exercise, we will explore the scientific rationale for using ensembles, how they are constructed and how ensemble forecasts can be visualised. A key question is how uncertainty from the initial data and the model parametrizations impact the forecast.

You will start by studying the evolution of the ECMWF analyses and forecasts for this event. You will then run your own OpenIFS forecast for a single ensemble member at lower resolutions and work in group to study the OpenIFS ensemble forecasts.

...

Column
width20%
Panel
titleTable of contents

Table of Contents
maxLevel1

...

Note
titleCaveat

In practise many cases are aggregated in order to evaluate the forecast behaviour of the ensemble. However, it is always useful to complement such assessments with case studies of extreme events, like the one in this exercise, to get a more complete picture of IFS performance and identify weaker aspects that need further exploration.

...

Panel
bgColorwhite
titleBGColorwhite
borderStyledotted
titleStorm track printed handout: ens_operborderStyledotted

Please refer to the handout showing the storm tracks labelled 'ens_oper' during this exercise. It is provided for reference and may assist interpreting the plots.

Each page shows 4 plots, one for each starting forecast lead time. The position of the symbols represents the centre of the storm valid 28th Oct 2013 12UTC. The colour of the symbols is the central pressure.

The actual track of the storm from the analysis is shown as the red curve with the position at 28th 12Z highlighted as the hour glass symbol. The HRES forecast for the ensemble is shown as the green curve and square symbol. The lines show the 12hr track of the storm; 6hrs either side of the symbol.

Note the propagation speed and direction of the storm tracks.  The plot also shows the centres of the barotropic low to the North.

Q. What can be deduced about the forecast from these plots?

Info

The plots in the handout can also be found in the 'pics' folder.

...