Composited Local Area Forecast Techniques
Final rept. Oct 1985-Oct 1987
AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA
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A previously developed advection forecast technique was modified to include data extracted from satellite imagery. A forecast experiment was then conducted using a data base gathered at AFGL during March 1984. This experiment was designed to test the usefulness of a 3-hour forecast updates, b a biquadratic interpolation, and c cloud and precipitation information from satellite imagery. The test results confirmed earlier tests in that advection using space-averaged 500-mb winds produced the best overall scores and that in general the scores for 1 - 15 hours were better than persistence. The age of the advection flow 3, 6 or 9 hours old did not affect forecast score, making updates useful. The biquadratic interpolation procedure produced better fits to observation than bilinear and appears to have improved forecasts. There was but a small benefit from adding satellite information to surface observations when forecasting cloud cover and hourly precipitation. the difficulties of trying to forecast even 30 to 50 percent of the time-change variance suggest that alternative approaches such as mesoscale modeling will be needed for accurate, reliable short-range forecasts. Keywords Aviation forecasting, Meteorology, Short-range forecasting, Mesoscale analysis and forecasting, Satellite meteorology.