Term
| Land/Water Distribution or Continentality |
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Definition
| The closer you are to a significantly large body of water, the lower the temperature range |
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Definition
| Three major wind belts of the general circulation in each hemisphere |
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Definition
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Definition
| Generally the higher it is, the cooler the temperature |
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Definition
September 22 in Northern Hemisphere, March 20th in Southern hemisphere.
Sun’s rays are perpendicular at the equator |
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Term
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Definition
| Dec 21 in N., rays are 23.5 degrees S. June 21 in S., rays are 23.5 degrees north |
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Definition
Mar. 20 (N) /Sept. 22 (S).
Suns rays are perpendicular at the equator |
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Definition
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Term
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Definition
| Heat energy is always transferred from higher to lower temperatures |
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Term
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Definition
| Molecular heat transfer in a solid |
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Term
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Definition
| Molecular heat transfer in a liquid or gas |
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Term
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Definition
| Heat transfer by electromagnetic waves- no medium (molecules) necessary |
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Definition
| Distance between wave crests or troughs of electromagnetic waves |
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Term
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Definition
Maximum wavelength = 2898/temperature
-The higher the temperature, he shorter the wavelength |
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Term
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Definition
| Total energy is MOSTLY dependent on temperature and that the higher the temperature, the more energy is emitted |
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Definition
| Shorter than .4 micrometers |
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Term
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Definition
| Longer than .7 micrometers |
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Term
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Definition
Energy that is scattered and/or reflected- No heating occurs
Earth’s is approximately 30%
Increase causes decrease in temperature
Decrease causes increase in temperature |
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Definition
| “Trap” (absorb) certain wavelengths of longwave radiation and the gases are heated. In turn, the gases radiate heat |
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Definition
| Allows the Earth to cool (give some of its heat back to space) by radiation |
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Term
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Definition
| If you give air a vertical “push”, it falls back into place or spreads horizontall |
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Term
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Definition
| If you give air a vertical “push”, it accelerates away from its initial position |
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Term
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Definition
| Air is stable if unsaturated (no clouds); unstable if saturated (clouds) |
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Term
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Definition
| If you give the air a vertical “push”, it will remain in its new position |
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Term
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Definition
| Cold fronts, wind shifts, orographic (mountains, hills that the air must go around, low pressure trough, stationary fronts, etc.) |
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Term
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Definition
| Day time heating (warm the surface) |
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Term
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Definition
| Temperature change with height |
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Term
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Definition
| Heating/cooling due only to compression/expansion of air |
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Term
| Dry adiabatic lapse rate (DALR) |
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Definition
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Term
| Saturated (or moist/wet) adiabatic lapse rate (SALR) |
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Definition
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Term
| Environmental Lapse rate (ELR) |
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Definition
| Temperature measured by the radio/rawinsondes. That is, how the temperature is actually changing with height. This can vary from hour to hour, day to day, measured twice a day |
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Term
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Definition
Have one or more of the following:
Hail greater than ¾ inches in diameter, funnel cloud, wind gusts stronger than 50 kts. |
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Term
| SHOW (Showalter) Index (SI) |
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Definition
SI = 0, air marginally unstable
SI < -6, air is extremely unstable, severe thunderstorms |
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Term
| LIFT (Lifted) Index (LIFT) |
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Definition
LIFT = 0 to -2, air marginally unstable
LIFT < -6, air is extremely unstable |
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Term
| SWEAT (Severe Weather Threat) SWET |
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Definition
SWET = 250-300 air is moderately unstable
SWET > 400 air is extremely unstable |
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Term
| Totals Totals Index (TOTL) |
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Definition
TOTL = 45-50 air is marginally unstable
TOTL = 55-60 air is very unstable |
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Term
| Covective Available Potential Energy (CAPE) |
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Definition
CAPE = 0 to 1000 j/kg, air marginally unstable
CAPE > 3500 j/kg, air is extremely unstable |
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Term
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Definition
| This is a low level temperature inversion that “caps” or suppresses convection |
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Term
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Definition
| In the troposphere if temperature gets warmer with height |
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Term
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Definition
| A vector quantity which is defined as the rate at which an object changes its velocity, that is, both speed and direction |
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Term
| Pressure gradient force (PGF) |
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Definition
| The rate at which air will accelerate depends on rate at which pressure changes with distance |
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Term
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Definition
| Holds the atmosphere to the earth. Directionally proportional to the mass of the 2 objects and inversely proportional to the square of the distance between them |
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Term
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Definition
| Acts opposite to the direction of the wind so it acts to slow the speed of the wind |
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Term
| Boundary layer/ Friction layer |
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Definition
| Area closest to the surface where friction is the greatest. Height depends on roughness of the surface |
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Term
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Definition
| Pressure decreases in the vertical and pressure is highest at the earth’s surface |
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Term
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Definition
| The balance between the pressure gradient force (PGF) and the Coriolis Force (COR) above the boundary or friction layer |
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Term
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Definition
| Acts to the right (left) of the wind direction in the Northern (Southern) Hemisphere |
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Term
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Definition
| A high speed core of air that is flowing geostrophically (no friction) |
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Term
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Definition
Usually about 60 Degrees N/S
-Aid in sensible heat exchanges
-Surface synoptic scale warm core highs and cold core lows are formed here |
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Term
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Definition
| Are the areas of the jet where the highest wind speeds are found |
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Term
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Definition
| If the flow of air into a column of air increases with time |
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Term
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Definition
| If the flow of air in a column of air decreases with time |
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Term
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Definition
| Winds coming together from different directions |
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Term
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Definition
| Winds slow down and come together |
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Term
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Definition
| Faster than geostrophic flow |
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Term
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Definition
| Slower than geostrophic flow |
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Term
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Definition
| Formed at jet stream level by speed convergence as jet stream air slows, these are warm core highs |
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Term
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Definition
| Formed at jet stream level by speed divergence as jet stream air speeds up, these are cold core lows |
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Term
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Definition
| Semi-permanent thermal highs are formed over cold surfaces such as high plateaus in the winter, these are cold core highs |
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Term
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Definition
| Semi-permanent thermal lows are formed over hot surfaces such as deserts in the summer, these are warm core lows |
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Term
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Definition
| A large body of air with relatively uniform thermal and moisture characteristics |
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Term
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Definition
| Two major types, oceans and continents (large deserts, polar/high plateau regions) |
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Definition
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Definition
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Definition
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Definition
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Definition
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Definition
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Definition
| Boundary between 2 air masses, only associated with cyclones and not with anticyclones, when passes, expect a wind shift (directional shift), temperature and moisture changes, and pressure changes |
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Term
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Definition
| Cold air replaces warmer air |
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Term
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Definition
| Warm air replaces cooler air |
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Term
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Definition
| Surface convergence boundary – little or no temp. difference, wind shift; precip. possible including thunderstorms, and in some cases, flooding |
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Term
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Definition
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Term
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Definition
| A moisture boundary between dry air and moist air |
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Term
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Definition
Boundary between 2 air masses aloft.
Common within cyclones that form east of the Rockies.
Air mass west of front is very cold; it originates in the upper troposphere/lower stratosphere, but as it descends, it warms and dries through adiabatic compression |
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Term
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Definition
The area between the cold front/dry line and the warm front.
The area where the most severe, convective weather usually occurs |
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Term
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Definition
| When the cold front “catches up” to the warm front |
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Term
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Definition
| When the air ahead of the warm front is cooler than the air behind the cold front |
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Term
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Definition
Area of low pressure.
Forms outside of the tropical latitudes |
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Term
| Extratropical latitudes (or mid-latitudes) |
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Definition
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Term
| Mid-latitude cyclones (extratropical cyclones) |
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Definition
| Usually are synoptic in scale which means they average 500 – 2000km in diameter and last from approximately 1 day to 1 week |
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Term
| Mid-latitude Cyclones (2) |
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Definition
| Cold fronts attached to mid-latitude cyclones bring colder air south and warm fronts attached to mid-latitude cyclones bring warmer air north |
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Term
| Mid-latitude cyclones (extratropical cyclones) 5 regions |
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Definition
1. Just east of the Rockies usually in eastern Colorado.
2. Just east of the Canadian Rockies usually in southern Alberta.
3. Just off the Texas-Louisiana coast.
4. Along the east coast of the USA, particularly off the coast of North Carolina.
5. Over the Bering Sea and Gulf of Alaska in the Pacific Ocean. |
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Term
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Definition
| Depends on 1 thing: cold air being “funneled” into the center of the cold core low from aloft. The result is depression of the geopotential heights and a steeper pressure gradient between the cold side of the system and the warm side of the system |
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Term
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Definition
| Is due to occlusion and subsequent mixing of the air masses as well as to the loss of divergence aloft |
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Term
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Definition
1. Special cases where the surface low is cutoff from the jet stream.
2. Surface low can sit and spin and move very little but it will weaken due to friction with the surface. |
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Term
| East coast cyclones usually form |
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Definition
1. Close to the time that a Rocky Mountain cyclone approaches the East coast and
2. After the passage of a cyclone formed in eastern Colorado or
3. After an older cyclone has progressed into Canada and is beginning to dissipate. |
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Term
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Definition
| Cumulonimbus clouds producing the thunderstorm embedded in stratiform clouds that are producing the snow |
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Term
| The Nor’easter (blizzard) of March 11-14th, 1888, or “The Great White Hurricane” |
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Definition
| Primarily affected the New York/New England area, but snow fell in the mountains of Tennessee up through Maryland and into New York and New England |
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Term
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Definition
1. Snow depth from 40 to 60 inches)
2. Winds averaged from 50 to 70mph
3. Temps. from 0 to 10F
4. Snowdrifts from 30 to 40 feet high
5. Problems with road transportation in New York City lead to development of the subway system! |
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Term
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Definition
| Usually “born” offshore near the Texas-Louisiana border, and then usually track up the East coast |
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Term
| Differences between the East coast and Gulf coast cyclones |
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Definition
1. Due to where they are “born”, Gulf coast cyclones can affect southeastern USA states more than the East coast cyclones.
a. Can produce heavy snow in Appalachians and urban corridor in the Piedmont.
b. Can produce devastating ice storms
c. Can produce severe convective weather such as tornadoes southern states such as Georgia and Florida |
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Term
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Definition
| Can also track up the Mississippi River valley |
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Term
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Definition
| Don’t track up the Mississippi River Valley as they form too far east and the general wind direction in the extratropics (30 to 70N) is from west to east. |
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Term
| The Superstorm of 12-14, March 1993 also called “The Blizzard of ‘93” or “The Storm of the Century” |
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Definition
| Started in the Gulf of Mexico |
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Term
| The Superstorm of 12-14, March 1993 also called “The Blizzard of ‘93” or “The Storm of the Century” |
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Definition
1. Affected 100,000,000 people killing 270 - most deaths in Florida due to flooding & tornadoes.
2. Total damages just due to snow was almost 6 billion dollars.
3. The Blizzard of ’93 began as a long-wave trough over the intermountain region of the USA on March 12th. A small closed, extratropical cyclone is in the Gulf of Mexico near Brownsville, Texas. Central pressure is about 1000 mb. |
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Term
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Definition
4. On 3/12, a jet max w/wind speeds of 100 - 150 kts. developed at the trough’s rear & positive vorticity developed in the left-hand exit quadrant.
5. Central pressure lowered at the rate of 1 to 2 mb/hour. By 7:00 PM on 3/12, the storm was south of Morgan City, LA w/a central pressure of 984 mbs. Ships reported sustained winds of 70 kts. A squall line developed ahead of the cold front. |
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Term
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Definition
| 6. Divergence aloft deepened the low. By 7:00 AM on 3/13, the center of the low was near Waycross, GA w/a central pressure of 971 mbs. Precip. fell from the Southeast to New England. Snow fell in panhandle of FL. w/blizzard conditions in AL & GA. In Columbia, SC, central pressure was 969.52 mb -lower than pressures in Columbia during Hurricane Hugo (Category. 4). |
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Term
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Definition
7. Heavy snow & high winds caused power outages to over 1 million homes; Parts of all major interstate highways were closed.
8. Central pressure dropped to 986.51 mb in Raleigh, NC, which was lower than pressures in Hurricane Hazel in 1954. |
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Term
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Definition
| 9. By 7:00 PM 3/13, the low’s center was near Wilmington, Delaware with a pressure of 960 mbs.; Blizzard conditions existed from the Appalachians to the Piedmont of NC & VA. At 7:00 AM 3/14, the center of the low was just off the south coast of Maine. Later during that day, the upper air trough moved offshore . |
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Term
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Definition
| Are influxes of unusually cold air into the middle or lower latitudes. |
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Term
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Definition
1. Can kill people:
a.) About 30 deaths per year due to direct exposure and approximately 600 due to hypothermia
b.) In the USA, most cold-related deaths are in the South, are elderly, and are male (almost 75%)
c). Livestock and domestic animals can also die |
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Term
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Definition
2. Can cause structural damage to buildings and other economic losses especially to crops.
a). Most economic damage in the South
b). Damages caused when pipes freeze and break and commercial slow-downs (people don’t shop, eat out as much)
c). Heating costs rise which can be a hardship for many |
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Term
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Definition
| 3. Can affect very large areas geographically |
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Term
| Formation of cold air masses (1) |
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Definition
1. Cold core high air masses form during winter at high latitudes or on high plateaus
a). Remember source regions for air masses: relatively flat, uniform surfaces with similar temperature and humidity characteristics with light winds.
b). The air mass must “sit” above the source region until the air mass takes on the temperature and humidity characteristics of the source region.
c). cA and cP are the coldest air masses. |
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Term
| Formation of cold air masses (2) |
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Definition
| 2. Higher the latitude, the longer the winter nights meaning that there is little or no sun and if there is sun, the sun angle is very low. This aids in cooling |
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Term
| Formation of cold air masses (3) |
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Definition
| 3. Cloud-free nights are good for radiative cooling (remember radiation cools as well as heats). |
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Term
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Definition
| Cracks in the ice develop on the Arctic Ocean allowing for the release of heat energy from the warmer, unfrozen ocean. |
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Term
| Intensification of cold core highs (1) |
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Definition
| Clear skies and calm winds favor additional radiative cooling |
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Term
| Intensification of cold core highs (2) |
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Definition
| Upper air convergence strengthens the high and the cold surface offsets much of the compressional (adiabatic) warming. |
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Term
| Intensification of cold core highs (3) |
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Definition
| Extensive snow pack keeps air cold. |
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Term
| The cold outbreaks of 2004 in the northeastern USA (1) |
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Definition
| Occurred in January and February, 2004 |
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Term
| The cold outbreaks of 2004 in the northeastern USA (2) |
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Definition
| Temps. in New York state and New England remained below freezing (32F or 0C) for almost 2 months. |
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Term
| The cold outbreaks of 2004 in the northeastern USA (3) |
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Definition
| During parts of January, high temps. in New York were below 0F. |
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Term
| The cold outbreaks of 2004 in the northeastern USA (4) |
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Definition
| Boston, Mass. Recorded its coldest January since 1893 |
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Term
| The cold outbreaks of 2004 in the northeastern USA (5) |
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Definition
| On January 13, Mt. Washington, NH the temps. fell to -45F. |
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Term
| The cold outbreaks of 2004 in the northeastern USA (6) |
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Definition
| The cold air mass was so dense, it drained southward despite winds above it that were moving from the west to the east |
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Term
| The USA cold wave of 1899 or “The Greatest Arctic outbreak in (recorded) history” or “The mother of all cold waves” (1) |
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Definition
| Occurred in February 1899 |
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Term
| The USA cold wave of 1899 or “The Greatest Arctic outbreak in (recorded) history” or “The mother of all cold waves” (2) |
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Definition
| Affected 2/3rds of the USA |
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Term
| The USA cold wave of 1899 or “The Greatest Arctic outbreak in (recorded) history” or “The mother of all cold waves” (3) |
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Definition
| Tremendous loss of livestock and crops particularly in the South |
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Term
| The USA cold wave of 1899 or “The Greatest Arctic outbreak in (recorded) history” or “The mother of all cold waves” (4) |
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Definition
| Cold especially severe in the South where cold was accompanied by snow in some locations |
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Term
| The USA cold wave of 1899 or “The Greatest Arctic outbreak in (recorded) history” or “The mother of all cold waves” (5) |
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Definition
| Temps. of -34F recorded in Dallas, TX.; -10F in Houston, TX.; and subfreezing temps. in Miami, FL |
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Term
| The USA cold wave of 1899 or “The Greatest Arctic outbreak in (recorded) history” or “The mother of all cold waves” (6) |
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Definition
| Washington, DC had 34 inches of snow; snow feel as far south as Ft. Myers, FL. |
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Term
| The USA cold wave of 1899 or “The Greatest Arctic outbreak in (recorded) history” or “The mother of all cold waves” (7) |
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Definition
| For the second time in recorded history, ice flowed in the Gulf of Mexico from the Mississippi River |
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Term
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Definition
| Combines the effects of wind and cold temperatures |
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Term
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Definition
| Solid and liquid surfaces lose heat more quickly when it is windy |
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Term
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Definition
| Liquids evaporate more quickly when it is windy – and evaporation cools |
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