Quantifying Sensible Weather Forecast Variability
Abstract
The long-term goal of this research is to examine the tactical-scale environmental predictability and provide a methodology by which it may be operationally assessed or monitored. Sensible weather occurs on small scales and the development and evolution of these small-scale features depends strongly on the larger scale environment. Synoptic-scale variability is represented by the individual members in a well-designed ensemble modeling system. The objective of this research is to quantify the local-scale variations in sensible weather elements, like fog, due to larger scale variability. The sensitivity of selected weather elements to synoptic-scale background variance will be quantified to identify when local-scale predictability may be high or low. The basic approach that is used to investigate the tactical-scale sensible weather forecast sensitivity is to conduct a variety of numerical model experiments. The time range of interest is the 0-48 hour forecast of sensible weather elements of operational interest. Sensible weather elements are generally not explicitly forecast by numerical models but will be derived algorithmically if needed by using appropriate combinations of explicitly forecast variables. These algorithms are applied across a set of ensemble forecasts to determine the ensemble-based probability of occurrence for a particular weather element. The NCEP GFS-based ensemble provides the basis for generating probabilistic forecasts of a variety of sensible weather elements in the 0-48 hour time period. Deterministic mesoscale forecasts for the region are available from a 3km resolution forecast from COAMPS and are used to derive mesoscale sensible weather forecasts that are tuned to this model. Additional COAMPS model runs are conducted using the NCEP ensemble members to initiate COAMPS forecasts to produce a mesoscale ensemble based on the predicted synoptic scale variance.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2011
- Accession Number
- ADA557118
Entities
People
- Wendell A. Nuss
Organizations
- Naval Postgraduate School