| CLOUD COVER |
Predominant cloud condition (e.g., cloudy,
pcldy, clear) |
| PRECIP TYPE |
Type of precipitation expected to occur such as rain,
showers, thunderstorms. |
| TEMP (24H TREND) |
Forecasted maximum or minimum temperatures in Fahrenheit
with a 24-hour trend noted in parenthesis. |
| RH % (24H TREND) |
Forecasted maximum or minimum relative humidity with a
24-hour trend noted in parenthesis. |
20FT WIND (MPH)
|
20-foot wind speed (mph) and direction (eight compass
points). |
| PRECIP AMOUNT |
Amount of liquid precipitation expected to the nearest
hundredth (0.01). |
| PRECIP DURATION |
How many hours are measurable precipitation expected to
last? |
MIXING HGT (M - MSL)
and
MIXING HGT (FT - MSL) |
A projected height in meters or feet above mean sea level
through which vigorous mixing will take place based
on the maximum temperature on a given day. It is
the height at which smoke will lose its buoyancy and stop
rising. It is valid for the afternoon hours when temperature
nears the predicted maximum. |
TRANSPORT WND (M/S)
and
TRANSPORT WND (MPH) |
The predicted average wind in meters per second or miles
per hour in the layer below the mixing height near the predicted
maximum (usually in the afternoon). |
| VENT INDEX |
The Ventilation Index parameter is obtained
by multiplying the mixing height in meters times the wind
speed in meters per second. |
| CAT DAY |
The Vent Index corresponds to a Category
Day
|
<2000 |
1 |
|
2000-3999 |
2 |
|
4000-7999 |
3 |
|
8000-16000 |
4 |
|
>16000 |
5 |
|
| MIX HGT 500 |
The temperature in Fahrenheit needed to achieve a mixing
height of 500 meters. If expected high temperature is cooler
than the 500 meter mixing height temperature, then the mixing
height parameter above will be less than 500 meters. |
| STABILITY CLASS |
The stability class based on wind, incoming solar radiation
(sun angle), and cloud cover. The more unstable the forecasted
stability class, the more readily a pollutant is dispersed.
|
Stability Class Description
|
|
A |
Extremely Unstable |
|
B |
Unstable |
|
C |
Slightly Unstable |
|
D |
Neutral |
|
E |
Slightly Stable |
|
F |
Stable |
|
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