Analysis & Forecast Chart Definitions
| Analysis |
Chart indicating current conditions of specified
elements.
|
| Convective weather |
Area of thunderstorms cause by surface
heating.
|
| Current Icing Potential |
An index of icing probability
over the U.S. with 0 indicating no icing and
1 indicating certain icing.
|
| Freezing Level |
Height of 32F temp level over the U.S.
indicated in decameters.
|
| Isotach |
A line connecting points of equal wind speed.
|
| Isotherm |
A line connecting points of equal temperature.
|
| K index |
Measure of atmospheric instability obtained by
comparing temp of an air parcel lifted from the
surface to actual air temp at a specified level.
|
| Lifted index |
Thunderstorm potential based on vertical
temperature lapse rate and moisture content.
|
| Millibar |
A unit used to measure of atmospheric pressure.
Standard pressure of 29.92 inches of mercury
equals 1013.25 mb.
|
| Precipitable Water |
The total amount of water that could
fall as precipitation if all the water vapor in a
vertical column of the atmosphere were condensed.
|
| Relative Humidity |
The amount of water vapor in the air
at a specified temperature and pressure
relative to the total amount it could hold at
those values.
|
| Significant Wave Height |
Height of the average of the
highest third of the waves.
|
| Winds Aloft |
Winds and temperature at 2nd standard height
(approx 1000-2000 ft), 14K, 24K, 34K ft.
|
| Vorticity |
A measure of rotation of a parcel of air.
In the Northern hemisphere positive is
counter clockwise, negative clockwise.
|
| 1000-500 mb Thickness |
Distance in decameters between the
height of the 1000 mb and 500 mb pressure levels.
|