American Meteorological Society Certification Weather Forecasting and Applied Meteorology 1 — Questions and Answers
Question 1: What is Numerical Weather Prediction (NWP)?
- Statistical analysis of historical weather patterns
- Computer simulation of the atmosphere using mathematical equations to forecast weather (Correct answer)
- Manual charting of weather systems
- Empirical forecasting from analogues
Correct answer: Computer simulation of the atmosphere using mathematical equations to forecast weather
NWP uses discretized mathematical equations governing atmospheric dynamics and physics to simulate future atmospheric states.
Question 2: What does ensemble forecasting provide compared to a single deterministic model run?
- Higher spatial resolution
- Probabilistic forecast information by running multiple model simulations with varied initial conditions (Correct answer)
- Faster computation time
- A single best-estimate forecast
Correct answer: Probabilistic forecast information by running multiple model simulations with varied initial conditions
Ensemble forecasting produces a range of possible outcomes by perturbing initial conditions and model physics, quantifying forecast uncertainty.
Question 3: The Model Output Statistics (MOS) technique improves NWP forecasts by doing what?
- Running the model at higher resolution
- Applying statistical relationships between model output and observed weather to reduce systematic errors (Correct answer)
- Combining multiple models equally
- Using only the most recent model run
Correct answer: Applying statistical relationships between model output and observed weather to reduce systematic errors
MOS uses regression relationships derived from historical model errors and observations to generate bias-corrected, site-specific forecast guidance.
Question 4: What is the primary purpose of data assimilation in NWP?
- Creating climate model scenarios
- Optimally combining model background fields with new observations to create the best initial state for forecasts (Correct answer)
- Downscaling global models to regional scales
- Generating ensemble members
Correct answer: Optimally combining model background fields with new observations to create the best initial state for forecasts
Data assimilation merges model background states with observations using statistical methods to produce the optimal analysis for initializing NWP forecasts.
Question 5: What is the Probability of Precipitation (PoP) in a weather forecast?
- The expected rainfall amount at a point
- The probability that at least 0.01 inches of precipitation will occur at any given point in the forecast area (Correct answer)
- The percentage of the forecast area that will receive rain
- The confidence level of the forecast model
Correct answer: The probability that at least 0.01 inches of precipitation will occur at any given point in the forecast area
PoP represents the probability that a specific point will receive measurable precipitation (≥0.01 inch) during the forecast period.
Question 6: What is the Lorenz predictability limit for atmospheric forecasting?
- 24 hours
- Approximately 2 weeks (Correct answer)
- 30 days
- 6 hours
Correct answer: Approximately 2 weeks
Edward Lorenz showed that due to chaotic atmospheric dynamics, deterministic weather forecasts lose skill beyond approximately two weeks.
American Meteorological Society Certification Weather Forecasting and Applied Meteorology 1
What is Numerical Weather Prediction (NWP)?