21st Conference on Weather Analysis and Forecasting/17th Conference on Numerical Weather Prediction

P1.73

Assessment of numerical weather forecasts over SW-Iceland

Thordur Arason, Icelandic Meteorological Office, Reykjavík, Iceland; and H. Ólafsson

Five years of 48 hours numerical forecasts of wind and temperature at different levels in the lower troposphere are compared to radiosonde observations at Keflavík, SW-Iceland. The overall accuracy of the forecasts is very good at all levels. At the lowest levels, there is however a slight cold bias in the forecasted temperatures during westerly winds. There is also a cyclonic bias in the forecasted wind direction in northerly flow. Both these biases can be attributed to the impact of non-resolved orography: The cold bias appears to be associated with an underestimation of an upstream blocking, and the wind bias to an underestimation of the wake south of Iceland.

Poster Session 1, Conference Posters
Monday, 1 August 2005, 5:30 PM-7:00 PM, Regency Ballroom

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