The NWS/NCAR “Forecaster Over the Loop” Fort Worth Operational Demonstration

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.

Auto-Nowcaster RoleAuto-Nowcaster Role

Forecaster USERDATA

ANC

Demonstration Demonstration ComponentsComponents

NWS CWSUDATA

ANC

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 developmentdevelopment

Green Regions - Green Regions - Moderate likelihoodModerate likelihoodRed 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

RegimeSelectionPolygo

nsNudging

&

Initiation Likelihood with No Initiation Likelihood with No Polygon WeightPolygon Weight

Initiation Likelihood with Polygon Initiation Likelihood with Polygon WeightWeight

Initiation Likelihood Initiation Likelihood NudgingNudging

Dryline Initiation CaseDryline Initiation CaseForecast: 2030 UTCRadar: 2030 UTC

Forecast: 2030 UTCRadar: 2130 UTC

April 21, 2005



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

Documents

The NWS/NCAR “Forecaster Over the Loop” Fort Worth Operational Demonstration