Atmospheric Science and Weather Analysis Flashcards

Which mechanism primarily drives the sea breeze circulation during daytime hours?

Answer: Differential heating between land and water creating a mesoscale thermal circulation

Sea breezes develop because land heats faster than adjacent water, creating lower pressure over land, which drives a low-level onshore flow from the relatively cooler sea surface.

The 'cap' or convective inhibition layer in a pre-storm environment is often associated with which synoptic feature?

Answer: An elevated mixed layer (EML) of warm, dry air originating from elevated terrain

An Elevated Mixed Layer (EML), commonly originating over the Mexican Plateau and advected eastward, creates a stable warm layer aloft (the 'cap') that suppresses convection until it is overcome by sufficient forcing.

In WSR-88D (NEXRAD) operations, 'aliasing' in Doppler velocity data refers to:

Answer: Velocity data folding when true velocities exceed the Nyquist velocity

Velocity aliasing (folding) occurs when the actual radial velocity of precipitation exceeds the radar's Nyquist velocity, causing the displayed velocity to wrap around to the opposite sign.

The thermal wind relationship states that the vertical shear of the geostrophic wind is proportional to:

Answer: The horizontal gradient of mean temperature between two pressure levels

Thermal wind is the vector difference between geostrophic winds at two levels and is directly proportional to the horizontal temperature gradient (baroclinicity) of the layer between those levels.

Which of the following cloud types is associated with severe icing hazards for aviation at mid-levels (10,000–20,000 ft)?

Answer: Altostratus (As) with supercooled liquid water droplets

Altostratus with supercooled liquid water droplets is a prime icing hazard because supercooled droplets freeze on contact with aircraft surfaces, forming rime or clear ice depending on temperature and droplet size.

The 'warm core' structure of a mature tropical cyclone differs from an extratropical cyclone in that the tropical cyclone has:

Answer: A warm temperature anomaly at its center extending through the depth of the troposphere

Tropical cyclones are warm-core systems where latent heat release in the eyewall creates a warm temperature anomaly throughout the tropospheric column, unlike cold-core extratropical cyclones.

The 'effective inflow layer' concept in severe thunderstorm forecasting defines the layer of air that:

Answer: Has sufficient CAPE (≥100 J/kg) and limited CIN (≤−250 J/kg) to contribute meaningfully to a storm's updraft

The effective inflow layer defines the portion of the low-level atmosphere with enough buoyancy (CAPE ≥100 J/kg) and low enough inhibition (CIN ≥−250 J/kg) to be ingested into and sustain a storm's updraft.