AMS Cheat Sheet 2026

The 30 highest-yield AMS facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What type of lapse rate produces absolutely unstable conditions? → Lapse rate greater than the DALR
2. What is Numerical Weather Prediction (NWP)? → Computer simulation of the atmosphere using mathematical equations to forecast weather
3. The globally averaged mean surface temperature of Earth is approximately: → 15°C (59°F)
4. Which surface feature is commonly found along the boundary between dry continental and moist Gulf of Mexico air in the US? → Dryline
5. What force causes wind to deflect to the right in the Northern Hemisphere? → Coriolis force
6. What is quantitative precipitation estimation (QPE) from radar? → Estimation of rainfall rates and totals from radar reflectivity using Z-R relationships
7. El Niño conditions in the tropical Pacific are characterized by: → Warmer-than-normal SSTs in the central and eastern tropical Pacific
8. What stability index combines wind shear and instability to assess severe weather potential? → Storm Relative Helicity (SRH)
9. What is the primary meteorological use of the GOES-R Advanced Baseline Imager (ABI)? → Multi-band visible, near-IR, and IR imaging for cloud, moisture, and fire detection
10. In ageostrophic wind theory, what causes air to deviate from pure geostrophic flow? → Acceleration, friction, and curvature effects
11. What is Rapid Intensification (RI) of a tropical cyclone defined as? → An increase of at least 35 mph in maximum sustained winds within 24 hours
12. Which surface type has the highest typical albedo? → Fresh dry snow
13. What is the purpose of dual-polarization radar technology? → Distinguish precipitation types (rain, snow, hail, graupel) and improve QPE
14. What does a negatively tilted trough indicate on upper-level charts? → Amplifying system and enhanced severe weather potential
15. Which greenhouse gas has the highest global warming potential (GWP) per molecule over a 100-year time horizon? → Sulfur hexafluoride (SF6)
16. The Köppen climate classification system primarily categorizes climates based on: → Temperature and precipitation patterns
17. What is the Bergen School cyclone model? → The Norwegian model describing extratropical cyclone life cycle
18. What is the purpose of ASOS (Automated Surface Observing System) stations in the US? → Automated surface weather observations for aviation and public use
19. 500 hPa height charts are used primarily to analyze what? → Mid-tropospheric steering flow and troughs/ridges
20. GPS radio occultation provides which type of atmospheric data? → Temperature and humidity profiles from GPS signal refraction
21. The current rise in global mean sea level is primarily attributed to: → Thermal expansion of seawater and mass loss from glaciers and ice sheets
22. What is a cold pool in convective meteorology? → A pool of cold, dense air at the surface formed by evaporative cooling from precipitation
23. What is the primary driving mechanism for the jet stream? → Horizontal temperature gradients in the troposphere
24. What type of front forms when a cold front overtakes a warm front? → Occluded front
25. The moist adiabatic lapse rate (MALR) is approximately what value near the surface? → 4–7°C/km
26. The Planck feedback in the climate system is classified as: → A fundamental negative feedback that stabilizes climate
27. What is the Saffir-Simpson Hurricane Wind Scale used to classify? → Hurricane intensity by maximum sustained wind speed (Categories 1–5)
28. Vorticity in meteorology refers to which property of atmospheric flow? → Spinning or rotating motion
29. What is the Level of Free Convection (LFC)? → The level where a lifted parcel becomes warmer than the environment and rises freely
30. What is the primary external driver of Earth's climate system? → Solar radiation