The shape of a severe thunderstorm echo on a radar screen which denotes the presence of a tornado. The echo is in the form of a hook, or appendage extending off of the main storm echo. Most often seen in the radar imagery of Midwest or great plains storms - very rarely seen in Arizona radar imagery.
A radar pattern sometimes observed in the southwest (right, rear) quadrant of a tornadic thunderstorm. The rain echo forms the hook pattern as air rotates around the strong updraft. The updraft is the hollow portion of the hook (looks like a backwards "J" or a 6) and is where the tornado would most likely be found (if the storm were to produce one). This signature is in the radar reflectivity field; Doppler radar's velocity information can help confirm the presence of a tornado, especially when a hook echo exists in the reflectivity field.
A radar reflectivity pattern characterized by a hook-shaped extension of a thunderstorm echo, usually in the right-rear part of the storm (relative to its direction of motion). A hook often is associated with a mesocyclone, and indicates favorable conditions for tornado development.
a pretty good tornado sign
a sign that a storm is possibly becoming tornadic
a strong signal that a supercell thunderstorm is about to or already has produced a tornado
A hook echo is displayed on radar reflectivity. It is a signature produced by precipitation held aloft that wraps around the mid-level mesocyclone. Since the mesocyclone has counterclockwise winds, the reflectivity signature of a hook echo will have a cyclonically shaped hook. The area free from reflectivity inside the hook is the updraft and inflow notch region of the supercell. A hook echo is one clue to a radar operator that a supercell has a potential of producing a tornado. Many of the violent tornadoes associated with classic supercells will show a distinct hook echo.
A radar pattern characterized by a hook-shaped (or figure 6-shaped) extension of a thunderstorm echo, usually in the southwest part of the storm. A hook is often associated with a mesocyclone, and indicates favorable conditions for tornado development.
A radar pattern sometimes observed in the southwest quadrant of a tornadic thunderstorm. Appearing like the number six or a fishhook turned in toward the east, the hook echo is precipitation aloft around the periphery of a rotating column of air 2-10 miles in diameter. The hook echo is often found in a local area favorable for tornado development. However, many tornadoes occur without a hook echo and not all hook echoes produce tornadoes.
radar reflectivity pattern observed in a thunderstorm, appearing like a fish hook and indicating favorable conditions for tornadic development. However, hook echoes and tornadoes do not always accompany each other.
The hook echo is one of the classical hallmarks of tornado-producing supercell thunderstorms as seen on weather radar. The echo is produced by rain, hail, or even debris being wrapped around the supercell. The National Weather Service considers the presence of a hook echo as sufficient to justify issuing a tornado warning.