American Meteorological Society Certification Mesoscale Meteorology 1 — Questions and Answers
Question 1: What type of mesoscale convective system organizes into a line of thunderstorms?
- Supercell
- Squall line (Correct answer)
- Mesoscale convective complex (MCC)
- Air mass thunderstorm
Correct answer: Squall line
A squall line is a linear band of convective storms organized by wind shear, often producing widespread damaging winds.
Question 2: A supercell thunderstorm is distinguished by what primary feature?
- Weak rotation and shallow depth
- A persistent, deep rotating updraft (mesocyclone) (Correct answer)
- Multicell cluster organization
- Very slow movement
Correct answer: A persistent, deep rotating updraft (mesocyclone)
Supercells are defined by a deep, persistent rotating updraft called a mesocyclone, which enables long-lived, organized severe convection.
Question 3: What is a Mesoscale Convective Complex (MCC)?
- A single large supercell thunderstorm
- A large, long-lived organized convective system with a circular cold cloud shield (Correct answer)
- A cluster of sea breeze cells
- A winter storm with embedded convection
Correct answer: A large, long-lived organized convective system with a circular cold cloud shield
An MCC is a large, nearly circular mesoscale convective system defined by specific cloud shield area and duration criteria in IR satellite imagery.
Question 4: Sea and land breezes are primarily driven by what mechanism?
- Upper-level divergence
- Differential heating between land and water surfaces (Correct answer)
- Coriolis force at the coast
- Orographic lifting
Correct answer: Differential heating between land and water surfaces
Sea and land breezes result from differential heating — land warms faster than water during the day, creating a pressure gradient that drives onshore flow.
Question 5: What radar feature indicates a strong rotating updraft in a supercell?
- Bright band
- Mesocyclone signature (Doppler couplet) (Correct answer)
- BWER (Bounded Weak Echo Region)
- Bow echo
Correct answer: Mesocyclone signature (Doppler couplet)
A mesocyclone signature on Doppler radar shows a couplet of approaching and receding velocities indicating rotation in a thunderstorm updraft.
Question 6: What is a derecho?
- A tropical squall system
- A widespread, long-lived wind storm produced by a fast-moving convective system (Correct answer)
- A type of cold front
- A severe thunderstorm limited to one county
Correct answer: A widespread, long-lived wind storm produced by a fast-moving convective system
A derecho is a widespread, damaging straight-line wind event produced by a fast-moving convective system extending at least 400 km.
American Meteorological Society Certification Mesoscale Meteorology 1
What type of mesoscale convective system organizes into a line of thunderstorms?