Question 1 of 15
Which cloud feature most directly precedes tornado formation?
Why: A persistent, rotating, lowering wall cloud marks the mesocyclone's strongest low-level rotation.
Question 2 of 15
A shelf cloud marks the leading edge of what?
Why: Cool air surging out from the downdraft lifts warm air, condensing into the low wedge-shaped shelf.
Question 3 of 15
Mammatus clouds usually indicate what?
Why: Mammatus hang beneath a storm's anvil — dramatic but not themselves dangerous.
Question 4 of 15
What is the 'flanking line'?
Why: The flanking line of cumulus towers along the storm's southwest side feeds the main updraft.
Question 5 of 15
An 'overshooting top' punching above the anvil signals what?
Why: Persistent overshooting tops mark updrafts strong enough to punch through the tropopause — a severe-weather red flag.
Question 6 of 15
What color often tints the sky under a hail-loaded storm?
Why: Sunlight scattered through dense water and ice in a deep storm gives the classic ominous green.
Question 7 of 15
What is 'scud'?
Why: Scud (cumulus fractus) is often mistaken for funnel clouds, but it doesn't rotate and isn't attached.
Question 8 of 15
The 'beaver tail' cloud band points toward what?
Why: A beaver tail is a flat inflow band feeding into the mesocyclone from the east or southeast.
Question 9 of 15
What distinguishes a roll cloud from a shelf cloud?
Why: Roll clouds are horizontal tubes detached from the parent storm; shelf clouds stay attached.
Question 10 of 15
A lowering that does NOT rotate is most likely what?
Why: Rotation is the key discriminator — spotters watch a lowering for minutes before calling it a wall cloud.
Question 11 of 15
What is a 'rain-free base'?
Why: The rain-free base marks the updraft region — where wall clouds and tornadoes form.
Question 12 of 15
In an HP (high-precipitation) supercell, why is the tornado often invisible?
Why: HP storms wrap precipitation around the mesocyclone — the reason Dixie Alley tornadoes are so dangerous.
Question 13 of 15
The 'clear slot' cutting into a storm base signals what?
Why: The RFD's drying slot often appears minutes before tornadogenesis.
Question 14 of 15
What does a 'striated' or 'barber pole' updraft indicate?
Why: Corkscrew striations show the whole updraft is rotating — the visual signature of a supercell.
Question 15 of 15
Anvil 'knuckles' (lumpy protrusions under the anvil edge) suggest what?
Why: Knuckles (reverse mammatus) mark vigorous overturning at the anvil — chasers read them as a strength cue.