The Operational Forecasting/Nowcasting of Precipitation Type in the Southeastern United States Type of Precipitation: Descriptive and Objective Guidance
Abstract
Frozen and freezing precipitation are hazardous to modem society. Even small amounts of frozen or freezing precipitation can significantly affect the public in the southeastern United States (SEUS). Improved forecasts of and specificity of precipitation type are critical to public and private sector responses to wintry precipitation. A significant percentage of frozen or freezing precipitation cases in this region are associated with shallow polar airmasses (i.e. Cold Air Damming (CAD) situations) and occur as a mix of wintry precipitation. CAD episodes are not routinely portrayed accurately by current operational numerical weather prediction models. Hence, right or wrong, there can be a lack of confidence in the model output statistics (MOS) generated from these models. As a supplement to the MOS, a Type of Precipitation: Descriptive and Objective Guidance (TOP DOG) approach consisting of regression equations (conditional probability) and nomograms is developed regionally and for individual stations in the SEUS. Due to the frequency of mixed precipitation events in the SEUS, emphasis is directed towards specifying a variety of precipitation subtypes (e.g., mixed liquid but non-accumulating frozen, all snow vs. mixed accumulating frozen).. Six-hour precipitation type guidance is derived directly from climatological (1973-1991) upper air sounding and surface data. TOP DOG uses logistical regression, more representative of the phenomena than linear regression used previously.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1994
- Accession Number
- ADA284456
Entities
People
- Craig A. Souza
Organizations
- North Carolina State University