Meteorology - Weather Patterns

Front 1

a boundary which separates two
different air masses.

Back 1

A front

Front 2

how big is a frontal boundary

Back 2

rather narrow;
between 15-200 km in width.
(10- 6 miles)

Front 3

do the two fronts mix?

Back 3

no retain their charachteristics

Front 4

NAme five types of fronts

Back 4

*warm and * cold,
S tationary
O ccluded
D ryline.

Front 5

IMPORTANT: No matter what front is in your area, what is displaced......

Back 5

lower density air

Front 6

how do you classify fronts

Back 6

type of air in area

Front 7

warm front

Back 7

Warm air advancing towards a retreating
cold air mass.

Front 8

slope of warm front

Back 8

Gentle slope: air travels 200 km
horizontally for every 1 km vertically (1:200).

Front 9

does it rain in a warm front

Back 9

VERY HUMID BUT Precipitation is generally light, though
thunderstorms can develop, especially in
Spring and Summer.

Front 10

cloud pattern for warm front

Back 10

• Cirrus clouds are found well in advance of
the front.
• The cloud bases lower approaching the
front, eventually changing over to stratus
type at the boundary.

Front 11

how warm fronts are depicted on maps

Back 11

Depicted on a weather map with red semicircles.

Front 12

do warm fronts move fast or slow

Back 12

Advance slowly (15-20 mph)

Front 13

winds in a warm front are from where

Back 13

Wind shifting from E/ESE to S/SE with
passage

Front 14

visibility in warm front

Back 14

Visibilities worsen on approach; improve
after passage.

Front 15

Cold front

Back 15

Cold air advancing into an area of warmer
air, forcing it to rise.

Front 16

slope of cold front

Back 16

steeper slope (1:100).

Front 17

what makes cold front have a steeper slope

Back 17

Friction slows the advance of the lower
section,

Front 18

do cold fronts move fast or slow

Back 18

cold fronts
advance more quickly (20-35 mph).

Front 19

why do cold fronts move so much faster

Back 19

the air is denser,

Front 20

is there precipitation in a cold front

Back 20

yes - usually thunderstorms
BUT little humidity or moisture in actual air

Front 21

why do cold fronts have more precipitation than warm fronts

Back 21

combination of speed and slope
causes thunderstorms to develop.

Front 22

clouds in a cold front

Back 22

Clouds are generally limited to
cumulonimbi at the boundary, though
some cirrus, from the anvils, may precede
the front.

Front 23

how are cold fronts depicted on maps

Back 23

Shown on maps as blue triangles pointing
in the direction of movement.

Front 24

winds in a cold front

Back 24

Winds are southerly ahead of the front
(SE to S); then switch to westerly
behind (SW to W).

Front 25

temperature with cold front

Back 25

Temperatures decrease markedly
behind the front.

Front 26

Occluded front

Back 26

Develops when a cold front overtakes a
warm front and forces both the warm front
and warm air to rise.

Front 27

how are occluded fronts depicted on maps

Back 27

Depicted as purple semicircles and
triangles on the same side.

Front 28

BAsiv weather with an occluded front

Back 28

Weather in advance is similar to warm
front; behind, the weather is similar to a
cold front.

Front 29

Two types of occluded fronts

Back 29

cold and warm.

Front 30

ONCE MORE - what happens to warm air in an occluded front

Back 30

WARM AIR RISES

Front 31

Where do Cold-type occlusions occur

Back 31

most
frequent east of the Rockies.

Front 32

Where do warm-type occlusions occur

Back 32

most
frequent west of the Rockies,
along the Pacific Coast.

Front 33

what makes warm air rise in occluded fronts

Back 33

the COLDEST air mass

Front 34

stationary front -
(stationary meaning doesnt move)

Back 34

A front which is moving less than 10 miles per
day.

Front 35

how are stationary fronts depicted on maps

Back 35

Depicted as alternating red semi-circles and
blue triangles, pointing in opposite directions.

Front 36

weather in a stationary front is similar to what other front

Back 36

warm -Precipitation is generally light, though
thunderstorms can develop, especially in
Spring and Summer.

Front 37

neither warm or cold front is advancing in stationary front - WHY

Back 37

upper level winds are parallel to the front.

Front 38

Dryline front

Back 38

Separates warm, dry (cT) air from warm,
humid (mT) air

Front 39

How does dryline front advance

Back 39

Front advances during day then retreats
at night

Front 40

wind direction in a dryline front

Back 40

Winds switch from S/SE to W/SW with
passage

Front 41

(cT)

Back 41

dry air

Front 42

(mT)

Back 42

humid air

Front 43

dryline fronts found mostly where

Back 43

Type of front that is Focus for thunderstorm activity over
Texas and Oklahoma during spring/early
summer

Front 44

polar front

Back 44

boundary between
the Polar Easterlies and the Westerlies.

Front 45

polar front THEORY

Back 45

• Developed by the Norwegians to explain
the development of Mid-Latitude Cyclones

Front 46

What Also marks the location of the Polar Jet
Stream

Back 46

polar front

Front 47

(cP)

Back 47

Continental Polar air masses

Front 48

what air masses do polar front seperate

Back 48

Usually mT and cP.

Front 49

in polar front, where do cyclones form

Back 49

along the frontal boundry

Front 50

why do Mid-Latitude Cyclones form

Back 50

result of upper-level
pockets of energy.

Front 51

Mid-Latitude Cyclone

Back 51

• A large scale transient atmospheric
disturbance.
• Usually composed of a low and a variety
of fronts,

Front 52

MLC stands for

Back 52

Mid-Latitude Cyclone - think big cloud mass in Day after tomorrow

Front 53

where do MCL occur

Back 53

Occur primarily between 35-70 N. latitude . In US that is everything north of Tennesse line and canada

Front 54

how large/wide is MCL

Back 54

Has a diameter of 1000 miles

Front 55

how long do MCL last and why

Back 55

Exist for 3-6 days, depending on upper level winds

Front 56

how fast do MCL move

Back 56

Moves 20-30 miles per hour

Front 57

what direction do MCL move

Back 57

west to
east.

Front 58

explain winds in a MCL

Back 58

cyclonic converging in middle

Front 59

cyclogenesis

Back 59

low pressure forming along
the Polar Front

Front 60

what causes low pressure to form in MCL

Back 60

result of upper level flow
which causes air to rise from surface

Front 61

what direction do cyclonic winds blow

Back 61

counter clockwise

Front 62

what is at center of cyclonic circulation

Back 62

low pressure

Front 63

life cycle of MCL

Back 63

*low pressure forms then
*winds circulate around low

Front 64

in an MCL - cold air goes where

Back 64

cold air circles southward from the north

Front 65

in an MCL - warm air goes where

Back 65

warm air circles northward from the south

Front 66

what moves the MCL from west to east

Back 66

jet stream

Front 67

MLC – Life Cycle

Back 67

*cold front advances rapidly over warm front
*occlusion occurs
*low pressure weakens - front dissipates

Front 68

Air converges from above and sinks
causing divergence at the surface.

Back 68

Mid-Latitude Anticyclones

Front 69

a mid latitude ANTI-Cyclone is also known as a

Back 69

high pressure

Front 70

weather pattern for a MLA

Back 70

• Clear, dry weather with no fronts attached.
• Can remain over the same area for days
thanks to ridges aloft.

Front 71

Bad side effects of MLA

Back 71

Stagnation ----leads to pollution, drought and
prevents MLC’s from moving into area.

Front 72

anti cyclonic circulation flows which direction

Back 72

clock wise

Front 73

Reasons polar front theory is NOT perfect?

Back 73

*doesn’t explain every weather event.
• Rainfall is not always associated with cold
and warm fronts.

Front 74

Better theory than polar front on weather patterns would be

Back 74

Conveyor Belt
Model.

Front 75

In Conveyor Belt Model, there are three major air masses in a MCL

Back 75

Dry warm and cold

Front 76

on map, how does MCL look

Back 76

like a comma - with a head tail and dry slot in the center