Troublesome Precipitation Events: A Challenge for Models and Humans Alike
Lance Bosart, SUNY Albany
This talk will feature a discussion of difficult-to-predict warm- and cold-season precipitation events. A warm-season example is predecessor rain events (PREs) that are observed to fall well in advance of landfalling and recurving tropical cyclones (TCs) in the eastern United States. An analysis of landfalling and recurving TCs between 1998-2006, when Doppler radar coverage was good, shows that PREs can occur in conjunction with upwards of 40% of these TCs. The associated PREs pose a significant forecast challenge because they tend not to be forecast very well by operational prediction models and they are frequently associated with heavy flood-producing rains. A cold season difficult-to-predict example would be observed mesoscale precipitation features that are frequently embedded within synoptic-scale cyclones. The forecast challenge in these situations is that while the anomaly correlation coefficient for the 36 h forecast 500 hPa height field may be above 0.90, indicative of a good forecast to modelers, the details of the important mesoscale precipitation features embedded within the cyclone may be poorly represented (if at all), indicative of a poor forecast to users.
SECURITY: If you are coming from outside the NOAA campus, please be advised that you will need an on-site sponsor. Please contact that person in advance of the seminar to be put on the list and allow 10 minutes extra on the day of the seminar. Please contact Joe Barsugli (303-497-6042) or Barbara Herrli (303-497-3876) at least a day before the seminar if you have any questions.