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Expert Awareness for Advanced Firefighters & Fire Behaviour Analysts | ||||||
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It is highly recommended that expert staff are tasked to the night shift Situation Unit if a foehn wind is in place over a fireground or is forecast to be so. Foehn events can be forecast, based on a synoptic air flow that is perpendicular to the main local range systems. Numerical weather models will indicate an event through the patterns of forecast temperature, relative humidity, rainfall and winds. Note that they may not show up in dew point products. Vertical flow products (either velocity or dP/dt) may show these events clearly. Analysts need to (1) assess vertical air flow; (2) review satellite imagery for cloud patterns and (3) discuss the situation with the duty forecaster. Air observers need to review the regional cloud pattern and its dynamics. Field observers need to assess the impact of winds flowing over the ranges, especially from the point of view of where they are reaching the surface. They also need to assess the large-scale fluctuations on wind direction which may cause foehn winds to switch on or off suddenly. Field observers should also monitor surface fire weather. Consideration may be given to issuing watchouts or Red Flag Warnings (Foehn wind). . |