The Tricellular Circulation is highly dynamic, varying with the seasons and bringing the Polar front back and forth across the USA. RANGE OF THE POLAR FRONT

THE POLAR FRONT IS THE REGION OF FORMATION OF ANTICYCLONES AND CYCLONES IN THE MID-LATITUDES. The anticyclone and cyclone are CLOSED Circulation wind patterns.

The anticyclone pressure gradient forces wind OUTWARD across isobars, and Coriolis Force forces the wind to turn rightward, while friction causes wind to move from HI to LOW pressure, resulting in a clockwise rotation and DIVERGENCE.

The cyclonic flow is INWARD in response to the pressure gradient, Coriolis, and frictional forces, And turns counterclockwise (CCW). Low pressure centers, hurricanes, and tornados are cyclonic.

Typical pattern of a mature mid-latitude Northern hemisphere cyclone, showing isobars, and wind velocities. The pressure gradient shown here is very high, resulting in hurricane force wind.

Relative advection brings air of different temperatures atop one another and results in a change In the environmental lapse rate, as shown the advection STEEPENS the lapse rate.

The frontal zone tilts TOWARD the cold front as the denser cold air under runs the lighter warm air.

When air velocity differs between regions (V1 and V2), convergence or divergence can occur. Convergence, as shown here, typically increases lapse rates, making air tend toward instability.

In addition to divergence and convergence, winds can be compressional (katabatic).

Cyclones and Anticyclones work together to create CIRCULATION CELLS in the Atmosphere. Both are an expression of VORTICITY in the atmosphere, and the resulting turbulence in the mid-latitudes.

VERTICALLY AS WELL AS HORIZONTALLY, MID-LATITUDE CYCLONES AND ANTICYCLONES OPERATE LIKE AN ATMOSPHERIC HEAT ENGINE !

CYCLOGENESIS. As shown here, a rotation has developed about a low pressure center as relative advection occurs, along with the effects of vorticity, producing a Wave Cyclone. The Wave Cyclone seen horizontally along the black line reveals The three dimensional nature of the process. Specific Clouds are Associated with Development of a Cyclone and its Passage.

Approach of a warm front

Approach of a Cold Front

Cyclogenesis, Development to Dissipation

Types of Occluded Fronts

The progression of wave cyclones through maturation and dissipation produces specific cloud types, wind directions, and precipitation that can aid in the prediction of weather.