# Weather Elements - MDL

# MOS Weather Element Definitions

MOS equations are developed to produce forecasts for the following elements. An acronym is given first, followed by the definition of the weather element and product elements produced associated with it, in the following form:

## ACRONYM (definition):

product elements

(Note that because of the lack of snowfall observations, the snowfall guidance will likely only be available for 24 hour periods).

## CIG (Ceiling Height):

Probability of Ceiling Height < 200 ft; Probability of Ceiling Height between 200 and 400 ft; Probability of Ceiling Height between 500 and 900 ft; Probability of Ceiling Height between 1000 and 3000 ft; Probability of Ceiling Height between 3100 and 6500 ft; Probability of Ceiling Height between 6600 and 12000 ft; Probability of Ceiling Height > 12000 ft; Categorical ceiling height (value from 1 to 7)

## CLOUDS (Total cloud amount):

Probability of clear skies; Probability of few or scattered cloud amount; Probability of broken cloud amount; Probability of overcast cloud amount; Categorical cloud amount (clear, scattered, broken, overcast)

## MAX (Maximum) and MIN (Minimum) Temperature

Daytime (7 a.m. - 7 p.m. LST) maximum; Nighttime (7 p.m. - 8 a.m. LST) minimum

## OBVIS (Obstruction to Vision):

Probability of blowing phenomenon; Probability of haze; Probability of light fog; Probability of dense fog; Probability of no non-precipitation obstruction to vision; Categorical obstruction to vision (blowing phenomenon, haze, mist, fog, none)

## POPC (Precipitation Characteristics):

Conditional Probability of Drizzle; Conditional Probability of Continuous Precipitation; Conditional Probability of Showers; Categorical precip. characteristics (conditional; value from 1 to 3)

## POP/QPF (Probability of Precipitation/Quantitative Precipitation Amount):

Probability of > 0.01 inches during a 6-h period; Probability of > 0.10 inches during a 6-h period; Probability of > 0.25 inches during a 6-h period; Probability of > 0.50 inches during a 6-h period; Probability of > 1.00 inches during a 6-h period; Categorical precipitation amount (trace or less; 0.01 - 0.09 inches; 0.10 - 0.24 inches; 0.25 - 0.49 inches; 0.50 - 0.99 inches; > 1.00 inches) during a 6-h period; Probability of > 0.01 inches during a 12-h period; Probability of > 0.10 inches during a 12-h period; Probability of > 0.25 inches during a 12-h period; Probability of > 0.50 inches during a 12-h period; Probability of > 1.00 inches during a 12-h period; Probability of > 2.00 inches during a 12-h period; Categorical precipitation amount (trace or less; 0.01 - 0.09 inches; 0.10 - 0.24 inches; 0.25 - 0.49 inches; 0.50 - 0.99 inches; 1.00 - 1.99 inches; > 2.00 inches) during a 12-h period Probability of > 0.01 inches during a 24-h period; Probability of > 0.10 inches during a 24-h period; Probability of > 0.25 inches during a 24-h period; Probability of > 0.50 inches during a 24-h period; Probability of > 1.00 inches during a 24-h period; Probability of > 2.00 inches during a 24-h period; Categorical precipitation amount (trace or less; 0.01 - 0.09 inches; 0.10 - 0.24 inches; 0.25 - 0.49 inches; 0.50 - 0.99 inches; 1.00 - 1.99 inches; > 2.00 inches) during a 24-h period

## PTYPE (Precipitation Type):

Conditional Probability of Freezing Rain or Ice Pellets; Conditional Probability of Snow; Conditional Probability of Rain; Categorical precip. type (conditional; value from 1 to 3)

## SNOW (Snowfall Amount):

Probability of > trace during a 6-h period; Probability of > 2 in. during a 6-h period; Categorical snow amount (none, trace - < 2 in, or > 2 in) during a 6-h period; Probability of > trace during a 12-h period; Probability of > 2 in. during a 12-h period; Probability of > 4 in. during a 12-h period; Probability of > 6 in. during a 12-h period; Categorical snow amount (none, trace - < 2 in, 2 - < 4 in, 4 - < 6 in, > 6 in) during a 12-h period Probability of > trace during a 24-h period; Probability of > 2 in. during a 24-h period; Probability of > 4 in. during a 24-h period; Probability of > 6 in. during a 24-h period; Probability of > 8 in. during a 24-h period; Categorical snow amount (none, trace - < 2 in, 2 - < 4 in, 4 - < 6 in, 6 in - < 8 in, > 8 in) during a 24-h period

## SUN (Solar Radiation and Sunshine):

Daily Insolation; Daily Percentage of Possible Insolation; Daily Hours of Sunshine; Daily Percentage of Possible Sunshine

## TMP (Temperature) and DP (Dew Point):

2-m Shelter Temperature; 2-m Shelter Dew Point

## TSTM (Thunderstorms) and SVR WX (Severe Weather):

Probability of thunderstorms for a 6-h period; Probability of thunderstorms for a 12-h period; Probability of thunderstorms for a 24-h period; Conditional Probability of Severe Weather for a 6-h period; Conditional Probability of Severe Weather for a 12-h period; Conditional Probability of Severe Weather for a 24-h period

## VIS (Visibility):

Probability of visibility less than or equal to 1/4 mi; Probability of visibility between 1/4 and 1/2 mi; Probability of visibility between 1/2 and 7/8 mi; Probability of visibility between 1 and 2 3/4 mi; Probability of visibility between 3 and 5 mi; Probability of visibility equal to 6 mi; Probability of visibility greater than 6 mi; Categorical visibility (value from 1 to 7)

## WIND (Wind Direction and Speed):

10-m wind speed; 10-m wind direction