Extended Abstract (464K)P1.4
The Latency of Model Generated Precipitation in Winter Time Cyclones
Holly M. Allen, University of Alabama, Huntsville, AL; and J. R. Mecikalski and C. B. Darden
In a collaborative effort between the National Weather Service Weather Forecast Office in Huntsville, Alabama and the University of Alabama in Huntsville, research is being conducted to better understand the onset of winter time precipitation associated with synoptic scale weather systems across the Southeast United States. Accurately depicting the initiation and timing of rain and snow development along the leading edge of an advancing system has proven to be a particularly difficult forecasting challenge. In extreme cases, the onset of model generated precipitation is as much as 12 hours behind the actual initiation time. It is believed the models’ problems lie in poor initial conditions, lack of data over the Gulf of Mexico and Mexico, or issues related to microphysical parameterizations. A case analysis of several events determined under which conditions these systems were most likely to form. Considerations were given to synoptic and mesoscale components, boundary layers, and moisture inflow streams. From these case studies, hypotheses were formed to determine what action should be taken to better predict the onset of precipitation in forecasting systems, such as AWIPS and NWP models. The ADAS/ARPS data simulation and forecast system is being used to assimilate satellite moisture information from GOES and AIRS in order to help the moisture deficiency seen in the southeast United States. The research findings are compiled and presented to the National Weather Service in order to develop a simple training program to improve the forecasting of winter time precipitation events.
Poster Session 1, LAND SURFACE AND HYDROLOGIC DATA ASSIMILATION POSTERS
Monday, 10 January 2005, 2:30 PM-4:00 PM
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