Search Results

You are looking at 1 - 5 of 5 items for :

  • Decadal variability x
  • Predictability and Dynamics of Weather Systems in the Atlantic-European Sector (PANDOWAE) x
  • All content x
Clear All
Olivia Martius and Heini Wernli

observed between 1958 and 2002 in conjunction with a positive North Atlantic Oscillation index during the last decades of the twentieth century ( Isotta et al. 2008 ). Although jet streams in the subtropics appear as a prominent climatological feature (e.g., Koch et al. 2006 ), their location, size, and amplitude are characterized by variability on synoptic time scales. The jet variability on the climatological time scale results from subtle forcing effects of slow-varying boundary conditions (e

Full access
Maxi Boettcher and Heini Wernli

1. Introduction During the last few decades, the dynamics of explosively deepening extratropical cyclones has been a key subject of meteorological research. Prime examples for such explosive cyclone developments are the devastating “Presidents’ Day cyclone” ( Bosart 1981 ) and the “Queen Elizabeth II storm” ( Gyakum 1983 , 1991 ; Uccellini 1986 ). These investigations led to the discovery of a surface vortex existing prior to the onset of rapid intensification. Gyakum et al. (1992

Full access
Julian F. Quinting and Sarah C. Jones

colored by decade: 1980–89 (black), 1990–99 (red), and 2000–10 (blue). The yellow line gives the mean recurving track ( T − 48 to T + 96 h) and the yellow star denotes the mean recurvature point. b. Identification of Rossby wave packets We use the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim; Dee et al. 2011 ) at 1° horizontal resolution to identify RWPs and to analyze the synoptic evolution from a composite perspective. A Hilbert transform filtering

Full access
Marlene Baumgart, Michael Riemer, Volkmar Wirth, Franziska Teubler, and Simon T. K. Lang

1. Introduction Numerical weather prediction has improved remarkably over the last decades (e.g., Bauer et al. 2015 ). Occasionally, however, very poor medium-range forecasts do still occur ( Rodwell et al. 2013 ). Forecast errors arise due to errors in the initial conditions and due to model deficiencies (e.g., Palmer and Hagedorn 2006 ). After 1–2 forecast days, localized errors may form that start to affect the synoptic-scale flow (e.g., Davies and Didone 2013 ; Martínez-Alvarado et al

Open access
Christian M. Grams and Heather M. Archambault

; Grams et al. 2015 ; Quinting and Jones 2016 ). Research during the last few decades has related the modulation of the midlatitude Rossby wave pattern during ET to the strong latent heat release by the transitioning TC. In essence, the upper-level divergent outflow of the transitioning TC impinging on the midlatitude waveguide enhances ridge building (e.g., Bosart and Lackmann 1995 ; Riemer et al. 2008 ; Archambault et al. 2013 ), in addition to the balanced flow, and triggers downstream

Full access