The NWS/NCAR The NWS/NCAR “Forecaster Over the “Forecaster Over the
Loop” Fort Worth Loop” Fort Worth Operational Operational
DemonstrationDemonstrationHuman Enhancement of a Human Enhancement of a Thunderstorm Nowcasting Thunderstorm Nowcasting
SystemSystem
Eric Nelson, Rita Roberts, Tom Saxen and Huaqing Cai
Ft. Worth Auto-Nowcaster Ft. Worth Auto-Nowcaster Demonstration Demonstration
2 Year Demonstration2 Year Demonstration Transfer Auto-Nowcaster Transfer Auto-Nowcaster
capabilities to NWS for gridded capabilities to NWS for gridded aviation forecasts.aviation forecasts.
Demonstrate improved forecast skill Demonstrate improved forecast skill incorporating human forecast input.incorporating human forecast input.
NCAR Auto-NowcasterNCAR Auto-Nowcaster
Routine (5mins) short-term (0-1hour) forecasts of Routine (5mins) short-term (0-1hour) forecasts of thunderstorm initiation, growth and decay.thunderstorm initiation, growth and decay.
Uses fuzzy logic to combine observations, NWP and Uses fuzzy logic to combine observations, NWP and forecaster input to generate nowcasts.forecaster input to generate nowcasts.
Extrapolation
Initiation Forecasts
Environmental conditions (RUC)Environmental conditions (RUC) Frontal likelihoodFrontal likelihood Layered stabilityLayered stability CAPE (max between 900 and 700 mb)CAPE (max between 900 and 700 mb) CIN (mean value between 975 and 900 CIN (mean value between 975 and 900
mb)mb) Mean 875 to 725 mb Relative HumidityMean 875 to 725 mb Relative Humidity Theta-e gradientTheta-e gradient
Boundary-layerBoundary-layer ConvergenceConvergence LI (based on METARS)LI (based on METARS) Vertical velocity along boundary (maxW)Vertical velocity along boundary (maxW) Boundary-relative steering flowBoundary-relative steering flow New storm development along boundaryNew storm development along boundary
CloudsClouds Clear or CumulusClear or Cumulus Vertical develop as observed by drop in Vertical develop as observed by drop in
IR tempsIR temps Other fieldsOther fields
3hr precip accum3hr precip accum
Blue Regions - Blue Regions - Little chance of storm Little chance of storm development development
Green Regions - Green Regions - Moderate likelihoodModerate likelihood
Red Regions - Red Regions - Areas of forecast initiationAreas of forecast initiation
Predictor Fields used forPredictor Fields used for Combined Likelihood of Initiation Combined Likelihood of Initiation
Data Sets Analysis Algorithms Predictor Fields
Forecaster Input
Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field
Final Prediction
Flow Chart for the Auto-Nowcaster System
Boundaries
Data Sets Analysis Algorithms Predictor Fields
Forecaster Input
Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field
Final Prediction
Flow Chart for the Auto-Nowcaster System
Boundaries
Regime
Selection
PolygonsNudging
&
Dryline Initiation CaseDryline Initiation CaseForecast: 2030 UTC
Radar: 2030 UTC
Forecast: 2030 UTC
Radar: 2130 UTC
April 21, 2005
Forecast: 2036 UTC
Radar: 2036 UTC
Forecast: 2036 UTC
Radar: 2136 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2042 UTC
Radar: 2042 UTC
Forecast: 2042 UTC
Radar: 2142 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2048 UTC
Radar: 2048 UTC
Forecast: 2048 UTC
Radar: 2148 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2100 UTC
Radar: 2100 UTC
Forecast: 2100 UTC
Radar: 2200 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2118 UTC
Radar: 2118 UTC
Forecast: 2118 UTC
Radar: 2218 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2142 UTC
Radar: 2142 UTC
Forecast: 2142 UTC
Radar: 2242 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2206 UTC
Radar: 2206 UTC
Forecast: 2206 UTC
Radar: 2306 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2224 UTC
Radar: 2224 UTC
Forecast: 2224 UTC
Radar: 2324 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2236 UTC
Radar: 2236 UTC
Forecast: 2236 UTC
Radar: 2336 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2248 UTC
Radar: 2248 UTC
Forecast: 2248 UTC
Radar: 2348 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2300 UTC
Radar: 2300 UTC
Forecast: 2300 UTC
Radar: 0000 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Forecast: 2312 UTC
Radar: 2312 UTC
Forecast: 2312 UTC
Radar: 0012 UTC
White Contour: 60min Initiation Nowcast; Color Shades=Reflectivity >20dbz
Improvements and Improvements and Continuing WorkContinuing Work
User interface transfer to NWS User interface transfer to NWS AWIPS systemAWIPS system
New regime for elevated convectionNew regime for elevated convection Fine tuning and evaluation of Fine tuning and evaluation of
existing regimesexisting regimes Quantitative statistics on overall Quantitative statistics on overall
human impact on forecastshuman impact on forecasts