Mechanics

gradient winds

• flow direction of the wind

• movement of the gradient wind in relation to the isobars

• where it is found

clockwise around highs, counterclockwise around lows

flows parallel to the isobars

found above 2,000 ft AGL

surface winds

• flow direction of the wind

• movement of the gradient wind in relation to the isobars

• where it is found

move clockwise around highs and counterclockwise around lows

blows across isobars at a 45 deg angle and has component of motion that moves air out of the high pressure and into the low

found below 2,000 ft AGL

Buys Ballots Law

if the wind is at your back, the area of low pressure will be to your left

jet stream and its speed

narrow band of strong winds at the top of the troposphere

100-150 kts can exceed 250 kts

sea breeze and its speed

when air above the land is hotter than the cold air over the ocea. the high pressure from the ocean moves towards the land creating winds replacing the warm air that moved upward

15-20 kts

land breeze

circulation is reversed from sea breeze producing an offshore breeze

hydrological cycle

process in which moisture changes state as it moves throughout the atmosphere

cloud

condensed water vapor that form on tiny particles in the air

condensation nuclei

dust, salt crystals, acid salts, etc. that allow condensation to have a surface to condense on

two principal cloud forms

cumuliform

stratiform

cumuliform cloud

lumpy, billowy cloud with a base showing a definite pattern or structure

stratiform cloud

uniform base, formed in horizontal, sheet-like layers

what type of air do stratiform and cumuliform for from

strat: stable

cum: unstable

low clouds

• height

• prefix

just above surface - 6500 ft AGL

no special prefix

stratus/ cumulus

middle clouds

• height

• prefix

6500 ft - 20,000 ft AGL

prefix of alto

high clouds

• height

• prefix

20,000 - 40,000 ft AGL

prefix of cirro or cirrus

special clouds with extensive vertical development

consists of towering cumulus and cumulonimbus clouds

bases found in low to middle cloud height and top extends to high cloud

nimbo/nimbus

violent or heavy

cumulonimbus

severe to extreme turbulence, hail icing, lightning

nimbostratus

thick, uniform, widespread clouds that build downwards

heavy continuous rain and moderate turbulence but no thunder

three characteristics of precipitation

showery

continuous

intermittent

showery and type of cloud

unstable air. sudden start and stop, abrupt intensity changes

cumuliform type clouds

continuous and type of cloud

stable air. steady with gradual changes

stratiform type clouds

intermittent and type of cloud

starts/stops at least once during the hour

both cumuliform and stratiform clouds

4 methods of lifting

frontal

orographic

convergence

thermal

3 conditions of stability

stable, netural stable, unstable

stable

colder air settles when the lifting action is removed

unstable

warmer air continues to rise

neutrally stable

same temperature air simply remains at the point where lifting action was removed

front

area of discontinuity that forms between two air masses

surface front

point where the front comes in contact with the ground

discontinuities used to locate and classify fronts

temperature, moisture, winds, and pressure

cold front

leading edge of an advancing cold air mass

cold front movement and wind shift

SE at 20 knots

90 deg SW to NW

squall line and how it is depicted on the map

line of violent thunderstorms

develop 50 to 300 miles in front of cold fronts

dashed double dotted lines

warm front movement and speed and wind shift

NE at 15 knots

90 deg SE to SW

warm front

warm air overtakes cooler air, usually slower

stationary front

neither air mass is replacing the other

no wind shift

occluded front

a faster moving cold front overtakes a slower moving warm front

two types: cold and warm

occluded front movement and wind shift

180 deg wind shift

NE 15-20 knots

the type of occulsion depends on

which front remains in contact with the ground