Horizontal Vorticity and Convection Flashcards
What are the three terms of the vertical vorticity equation?
1) advection
2) tilting
3) stretching
____ horizontal vorticity is generated at the leading edge of the cold pool, causing the cold pool to ___ along the surface
negative | causing cold pool to move (or spread) along the sfc
There is ___ pressure underneath cold air, which causes the cold air to accelerate _____
higher pressure | accelerate outward
The ambient air flows ___ the cold pool from the east, and is lifted at the ___ edge of the cold pool
flows toward the cold pool | lifted at the leading edge
In the absence of any other sources of horizontal vorticity, the lifted air is then guided ___ by the cold pool general circulation
guided rearward
In the absence of any generated ____ buoyancy produced by lifting (i.e. if the ambient air does not reach its LFC), the ambient air will not travel any farther above the cold air
positive buoyancy
When a cold pool has vertical wind shear, a positive environmental vorticity couples with negative vorticity at the edge of the gust front to develop an ____ ____
updraft jet
When the vertical wind shear vector points to the east, it signifies ____ horizontal vorticity
positive horizontal vorticity
If the magnitude of the positive horizontal vorticity associated with the ambient shear is the same as the magnitude of the negative horiz vorticity produced along the leading edge of cold air, then the air approaching the cold pool will tend to rise as a ____ ____ ___
vertically-oriented jet (updraft jet)
This produces ____ lifting at the leading edge of the cold air than from the case of no ambient vertical wind shear
deeper lifting
When the cold pool interacts with vertical wind shear, the ambient air has a much greater chance of being lifted to its ____
LFC
Evenly matched, but opposite horiz vorticity in the vorticity dipoles maintains ___ ____
deep updraft
The triggering of convective cells is favored along the ____ portion of a spreading cold pool
downshear
The strongest, most-lived convective systems will be produced when there is a strong ___ ___ ___ to balance the cold pool generated circulation
LL vertical wind shear
____ shear is important in how a storm’s updraft may evolve
environmental shear
How can you evaluate environmental wind shear?
plotting a hodograph
hodographs depict the _____ ____ of the horiz wind
vertical distribution
with hodographs, points are plotted as a function of ___ ____ and ____
wind direction and speed
with hodographs, each point represents the ____ wind at a specified elevation
horizontal wind
with a hodograph, wind vectors for each level are produced by connecting the hodograph’s ____ origin point with the ____ point
central origin with the plotted point
with hodographs, ____ shear vectors are produced by connecting two sequential points
layer shear vectors
The ___ ___ is the leading edge of the rain-cooled air in the planetary boundary layer
gust front
The gust front forms along ___ ___ of mesoscale domes of rain-cooled air that result from the amalgamation of ____-____ downdrafts from individual thunderstorm cells
leading edges | evaporatively-cooled
thunderstorm cold pools are associated with ___-___ and may actually be crudely analyzed on a synoptic surface chart
meso-highs (i.e. bubble highs)
The gust front is a ____ discontinuity
density
___, ___ surface air flows outward from the meso-high
cooler, denser
High theta-e air is uplifted ___ the outward-flowing cold pool
above
New convection may form in association with this uplift if the lifted parcels can reach their ____
LFC (level of free convection)
____ ____ ___ can play a major role in determining how high a parcel may be lifted prior to reaching its LFC
environmental wind shear
gust front passage is characterized by what 5 things?
1) wind shift and abrupt increase in wind speed
2) abrupt temperature drop (most of the time)
3) sharp pressure rise
4) arc cloud (if BL is moist)
5) strong VWS
A gust front is a ____ feature
mesoscale
The ___ ___ ___ represents the gust front
low cloud line