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The Forecast Process

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Observation

-- Surface obs
-- Meso-networks
-- Profilers
-- Upper air obs
-- Radar
-- Satellite images
-- Aircraft
-- Satellite soundings / remote sensing

Analysis

-- Turn observations into charts
-- Hand analysis where needed
-- Use contour lines vs. color blobs: quantitative, gradients, etc.
-- Study and absorb chart detals
-- SkewT
-- Fronts
-- Geostrophic, ageostrophic
-- Troughs and Ridges
-- Jets, Jet Streaks
-- Advection
-- Look out window
-- Example

Diagnosis

-- Achieve unified picture of the state of the atmosphere
-- Blend all analysis into 4D conceptual model
-- Apply theory
-- Understand different scales at work
-- Experience and expertise
-- Example

Prognosis

First establish unified picture of the atmosphereic state. Then carry that picture forward into the future. The numerical models will be your primary tool for doing this.

-- Numerical Models
-- Understand model output
-- Apply theory
-- Subjective techniques: Continuity, extrapolation, patterns, rules of thumb, etc.
-- Nowcasting
-- Don't go it alone: map discussions

Human Forecasting

Models have made forecasting easier, but expectations are higher!

Uncertainty

-- Assess undertainty for all aspects of the forecast
-- Use Experience and Expertise
-- Use model ensembles

Risk / Threat / Impact

-- Severe thunderstorms, tornadoes, winds, heavy rain, lightning, flooding, snow, freezing rain, etc.
-- Consider possible risks and threats due to expected weather
-- Assess impact to target audience: aircraft, boating, traffic, etc.
-- Watches and Warnings
-- Uncertainty vs. level of potential impact
-- Important events: parades, fireworks, games, festivals, inauguration, etc.

Nowcasting

-- Detailed description of current weather
-- Forecasts obtained by extrapolation for 0 to 6 hours ahead
-- Forecasts of small features (eg. individual storms) possible
-- Watches, warnings
-- Main technique: Extrapolation of radar echos
-- Supporting Techniques: Hourly surface analysis, satellite images
-- Requires ongoing and full understanding of the 4D atmospheric state

Communication

-- Communicating uncertainty: chance, likely, probability, etc.
-- POPs (Probability of Precipitation)
-- Communicate risk/threat: watches, warnings
-- Standardized language and products
-- Custom info for specific needs: aircraft, boating, agriculture, construction, etc.
-- Maps and graphics for target community
-- Weather Presenters

Human Forecast Products

-- Text Products
-- Web sites (eg. weather.gov)
-- Discussions
-- Forecast Maps
-- QPF
-- NDFD (National Digital Forecast Database)
-- TV graphics
-- Watches, warnings, special weather statements, etc. -- AIRMETS, SIGMETS (aircraft alerts) -- Etc.