is a cloud
with an area of rainfall which is significantly elongated.
Rainbands can be stratiform
, and are generated by
differences in temperature. When noted on weather radar
imagery, this precipitation
elongation is referred to as banded structure. Rainbands within
tropical cyclones are curved in orientation. Tropical cyclone
rainbands contain showers and thunderstorms that, together with the
eyewall and the eye, constitute a hurricane or tropical storm
. The extent of
rainbands around a tropical cyclone can help determine the
Rainbands spawned near and ahead of cold
can be squall lines
able to produce tornadoes
associated with cold fronts can be warped by mountain barriers
perpendicular to the front's orientation due to the formation of a
low-level barrier jet
. Bands of
thunderstorms can form with sea breeze
and land breeze
boundaries, if enough
moisture is present. If sea breeze rainbands become active enough
just ahead of a cold front, they can mask the location of the cold
front itself. Banding within the comma head precipitation pattern
of an extratropical cyclone
can yield significant amounts of rain
. Behind extratropical cyclones, rainbands can
form downwind of relative warm bodies of water such as the Great Lakes.
If the atmosphere is cold enough, these
rainbands can yield heavy snow.
A February 24, 2007 radar image of a
large extratropical cyclonic storm system at its peak over the
central United States.
Note the band of thunderstorms along its trailing cold
Rainbands in advance of warm occluded
and warm fronts
with weak upward motion, and tend to be wide and stratiform in
nature. In an atmosphere with rich low level moisture and vertical
, narrow, convective rainbands
known as squall lines
generally in the
's warm sector, ahead of strong cold
fronts associated with extratropical cyclones. Wider rain bands can
occur behind cold fronts, which tend to have more stratiform, and
less convective, precipitation. Within the cold sector north to
northwest of a cyclone center, in colder cyclones, small scale
, or mesoscale
, bands of heavy snow can
occur within a cyclone's comma head precipitation pattern with a
width of to . These bands in the comma head are associated with
areas of frontogensis, or zones of strengthening temperature
contrast. Southwest of extratropical cyclones, curved
flow bringing cold air across the relatively warm Great Lakes can lead to narrow lake effect snow bands which
bring significant localized snowfall.
Rainbands exist in the periphery of tropical cyclones, which point
towards the cyclone's center of low
. Rainbands within tropical cyclones require ample
moisture and a low level pool of cooler air. Bands located to from
a cyclone's center migrate outward. They are capable of producing
heavy rains and squalls
of wind, as well as
tornadoes, particularly in the storm's right-front quadrant. Some
rainbands move closer to the center, forming a secondary, or outer,
within intense hurricanes. Spiral
rainbands are such a basic structure to a tropical cyclone that in
most tropical cyclone
, use of the satellite-based Dvorak technique
is the primary method used
to determine a tropical cyclone's maximum sustained winds
. Within this
method, the extent of spiral banding and difference in temperature
between the eye
and eyewall is used to
assign a maximum sustained wind and a central pressure. Central pressure
values for their
centers of low pressure
this technique are approximate.
Forced by geography
Convective rainbands can form parallel to terrain on its windward
side, due to lee
triggered by hills just upstream of the cloud's
formation. Their spacing is normally to apart. When bands of
precipitation near frontal zones approach steep topography, a
low-level barrier jet stream
parallel to and just prior to the mountain ridge, which slows down
the frontal rainband just prior to the mountain barrier. If enough
moisture is present, sea breeze
fronts can form convective
rainbands. Sea breeze front thunderstorm
lines can become strong enough to
mask the location of an approaching cold front by evening. The edge
of ocean currents
can lead to the
development of thunderstorm bands due to heat differential at this
interface. Downwind of islands, bands of showers and thunderstorms
can develop due to low level wind convergence downwind of the
island edges. Offshore California, this has been noted in the wake of cold
- Glossary of Meteorology (2009). Rainband. Retrieved on 2008-12-24.
- Glossary of Meteorology (2009). Banded structure. Retrieved on 2008-12-24.
- Owen Hertzman (1988). Three-Dimensional Kinematics of Rainbands in Midlatitude
Cyclones. Retrieved on 2008-12-24
- Yuh-Lang Lin (2007). Mesoscale Dynamics. Retrieved on 2008-12-25.
- Richard H. Grumm (2006). 16 November Narrow Frontal Rain band Floods and severe
weather. Retrieved on 2008-12-26.
- Glossary of Meteorology (2009). Prefrontal squall line. Retrieved on
- K. A. Browning and Robert J. Gurney (1999). Global Energy and Water Cycles. Retrieved on
- KELLY HEIDBREDER (2007). Mesoscale snow banding. Retrieved on
- David R. Novak, Lance F. Bosart, Daniel Keyser, and Jeff S.
Waldstreicher (2002). A CLIMATOLOGICAL AND COMPOSITE STUDY OF COLD SEASON
BANDED PRECIPITATION IN THE NORTHEAST UNITED STATES. Retrieved
- Glossary of Meteorology (2009). Tropical cyclone. Retrieved on 2008-12-24.
- A. Murata, K. Saito and M. Ueno (1999). A Numerical Study of Typhoon Flo (1990) using the
MRI Mesoscale Nonhydrostatic Model. Retrieved on 2008-12-25.
- Yuqing Wang (2007). How Do Outer Spiral Rainbands Affect Tropical
Cyclone Structure and Intensity? Retrieved on 2008-12-26.
- NWS JetStream – Online School for Weather (2008). Tropical Cyclone Structure.| National Weather Service. Retrieved
Oceanic and Atmospheric Administration (1999). Hurricane Basics. Retrieved on 2008-12-24}}
- Jasmine Cetrone (2006). Secondary eyewall structure in Hurricane Rita:
Results from RAINEX. Retrieved on 2009-01-09.
- University of
Wisconsin–Madison (1998). Objective Dvorak Technique. Retrieved on
- Atlantic Oceanographic and Meteorological Laboratory (2007).
Subject: H1) What is the Dvorak technique and how is it
used? Retrieved on 2006-12-08.
- Daniel J. Kirshbaum, George H. Bryan, Richard Rotunno, and Dale
R. Durran (2006). The Triggering of Orographic Rainbands by
Small-Scale Topography. Retrieved on 2008-12-25.
- Daniel J. Kirshbaum, Richard Rotunno, and George H. Bryan
(2007). The Spacing of Orographic Rainbands Triggered by
Small-Scale Topography. Retrieved on 2008-12-25.
- J. D. Doyle (1997). The influence of mesoscale orography on a coastal jet and
rainband. Retrieved on 2008-12-25.
- A. Rodin (1995). Interaction of a cold front with a sea-breeze front
numerical simulations. Retrieved on 2008-12-25.
- Eric D. Conway (1997). An Introduction to Satellite Image
Interpretation. Retrieved on 2008-12-26.
- Ivory J. Small (1999). AN OBSERVATIONAL STUDY OF ISLAND EFFECT BANDS:
PRECIPITATION PRODUCERS IN SOUTHERN CALIFORNIA. Retrieved on