Radar interpretation

Radar signatures

Every radar signature that reveals severe weather. Learn to read radar like a chaser.

Reflectivity signatures

Hook echo

Curved echo indicating mesocyclone rotation. Classic tornado signature.

Bow echo

Curved line of storms indicating strong straight-line winds.

Weak echo region (WER)

Cavity in storm indicating strong updraft.

BWER

Bounded WER — strongest storms.

Notch

Precipitation gap indicating rotation.

V-notch

V-shaped notch in reflectivity.

Fine line

Boundary — outflow or dryline.

Line echo wave pattern

S-shaped bow line.

Velocity signatures

Mesocyclone

Adjacent red/green couplet.

Tornado vortex signature (TVS)

Small tight rotation.

Gate-to-gate shear

Extreme velocity difference between adjacent gates.

Bookend vortex

Rotation at bow echo end.

Convergence

Winds coming together.

Divergence

Winds spreading apart.

Rear inflow jet

Air punching into back of bow.

Storm motion

Direction and speed.

Dual-pol signatures

Tornado debris signature (TDS)

Radar debris ball. Confirms tornado.

Correlation coefficient drop

CC low in debris.

Differential reflectivity

ZDR — hail vs rain.

Big drops

Melted hail.

Three-body scatter

Hail spike downstream.

Ice crystal identification

Different from rain.

Timing considerations

Radar updates every 4-6 minutes typically.
Volume scan takes time.
Real-time not always exactly real-time.
Between scans much can happen.
Fast-moving storms cover ground.
Position awareness.
Backup with visual when possible.

The specific signatures for tornado warning

Persistent mesocyclone.
Low-level rotation.
Hook echo development.
RFD notch.
Debris signature.
Radar operator decision.
Impact-based tag application.
Warning issuance.

For chasers reading radar

RadarScope Pro standard tool.
Level 2 data for detail.
Velocity overlay always.
CC and ZDR when needed.
Multi-panel views.
Historical playback for storm evolution.
Attribute overlays.
GPS overlay for position.
Chase-informed reading.
Combined with visual observation.

For the public reading radar

Free apps show reflectivity.
Colors indicate intensity.
Green light rain to red/purple heavy.
Purple/pink can indicate hail.
Do NOT rely on public radar alone.
Warnings from NWS most important.
App-based warnings.
Multiple information sources.
Never chase from consumer apps.
Trust NWS.

The chase-day radar workflow

Morning: check for developing storms.
Midday: check for supercell development.
Storm phase: continuous monitoring.
Rotation development: alert.
Tornado potential: warning phase.
Position: safe distance.
Movement tracking.
Storm cycles: watch for reformation.
Post-storm: continued monitoring.
End of day: forecast review.

Historical radar evolution

WSR-57: reflectivity only, 1957.
WSR-88D: Doppler, 1988.
Dual-pol upgrade: 2013 nationwide.
Phased-array: some pilots.
MRMS: 2010s national mosaics.
Warn-on-Forecast: coming.
AI augmentation: developing.
Continuous improvement.