Weather Forecasting and Applied Meteorology Flashcards

What is Numerical Weather Prediction (NWP)?

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.

What does ensemble forecasting provide compared to a single deterministic model run?

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.

The Model Output Statistics (MOS) technique improves NWP forecasts by doing what?

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.

What is the primary purpose of data assimilation in NWP?

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.

What is the Probability of Precipitation (PoP) in a weather forecast?

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.

What is the Lorenz predictability limit for atmospheric forecasting?

Answer: Approximately 2 weeks

Edward Lorenz showed that due to chaotic atmospheric dynamics, deterministic weather forecasts lose skill beyond approximately two weeks.