Mid-latitude cyclone

Whatis a mid-latitude cyclone?

-Themid-latitude cyclone is a synoptic scale low pressure device that has actually cyclonic(counter-clockwise in north hemisphere) flow that is found in the middlelatitudes (i.e., 30�N-55�N)


o over there is a location (tropics vs.mid-latitudes) and size difference in between hurricane and mid-latitude cyclone

�Typicalsize the mid-latitude cyclone = 1500-5000km in diameter

�Typicalsize that a hurricane or dry storm = 200-1000km in diameter

Here is a photo of a common mid-latitudecyclone and hurricane. Notice the size difference.

You are watching: How does surface air flow in a middle-latitude cyclone in the northern hemisphere


How go the mid-latitudecyclone form (for a longer description read pages 219-228)

1.Frompolar prior theory, we know that in the mid-latitudes over there is a boundary betweencold dry (cP) air come the north and also warm moist (mT) air to the southern

2.Alongthis boundary a counter-clockwise circulation can collection up at the surface, whichacts to take warmth air increase from the south and cold air under from the north. Thisis referred to as cyclogenesis.

3.Inthe facility of this circulation, there is massive convergence (all the waiting ismoving in towards the center of the circulation lot like as soon as you make a whirl-poolin a pool, all the leaves and also stuff floating around moves towards the center).When all that air access time the center, we have rising motion since it has nowhereelse come go.

4.Ifthe top levels room favorable for cyclone development, then there is a regionof divergence aloft above the developing Low-pressure center. This will certainly helppull the air that is converging in ~ the surface upward and continue to build thesurface cyclone. (The top levels additionally steer the system and make the progresseast (like we learned earlier)).

a.Ifthe upper levels aren�t favorable for cyclone development, the cyclone won�tgrow and the massive convergence right into the low at the surface ar will simply pile increase andfill in the Low and it will decay.

b.Referto the second figure below for the optimal situation.

5.Ifthe top levels room favorable, then the mid-latitude cyclone will continue todevelop and also bring increase mT air in the warmth sector and bring down cP waiting in thecold sector.

a.ThemT wait rises as it moves the end ahead that the short helping to deepen the Lowpressure facility to the eastern and help it move along

b.ThecP air sink behind the system and also fills in the low on the backside alsohelping to move the device along

i.Itis this transfer of power that both strengthens and propagates themid-latitude cyclone!

6.Oncethe mid-latitude cyclone is totally developed, well-defined fronts appear.

7.Asthe mid-latitude cyclone will maturity, the central pressure will certainly be in ~ itslowest and also the occluded former will start to form (as the cold front captures upto the heat front).

8.Oncethe system is occluded (all the heat air is over the cold air) the fixed convergenceacts to fill in the Low and therefore the pressure increases in the Low and also thesystem decays.

See more: The Wind In The Willows Sparknotes, The Wind In The Willows Summary

Evolution the a mid-latitude cyclone. Every figurefollows the description above 1-8



Theabove figures were taken indigenous www.u.arizona.edu/~korine/230/chap10_figs.htm


Diagram of circulation (circulation) throughout thedepth of the troposphere


Wheredo mid-latitude cyclones typically type (in phibìc America in winter)? (Remember the cycloneslike to develop along air mass boundaries)

-Leeside the the Rockies = Lee Cyclones

o Alberta Clippers

�FASTMOVING and also usually don�t have actually too much precip associated with them since theyare much from a humidity source


�IntenseLow, with solid warm wait advection in the warm sector, really cold temps in thecold sector. If over there is a most gulf moisture to work with, they there isusually sleet, freezing rain and rain linked with the heat front, solid thunderstormsalong the southern edge of the cold front and also snow along the backside and also tothe NW that the low (even BLIZZARDS)

-Alongthe east Coast

o Gulf Low

�Formalong the southern coastline where over there is a thermal boundary in between the warmocean and also cool land. Usually have a the majority of precip connected with them due to the fact that theyare so close to the ocean

oHatterasLow and also Nor�easters (aka ��bomb�cyclones)

�Theseare the most INTENSE systems and they type along the thermal border betweenthe heat Gulf Stream and the cold Atlantic coast. Lock can carry flooding rainsalong the coast and also several feet of snow further inland as they use the oceanas a vast source of the moisture. These likewise develop an extremely quickly and sometimeshave push drops that 24mb in a solitary day. V a pressure drop of thismagnitude you have the right to imagine how rapid the winds are roughly these things.

What room their common tracks? watch diagrambelow


Precip fads (and types),winds, temperatures, fronts, upper level flow and clouds that are approximately a typicalmid-latitude cyclone in winter.