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Weather Elements

NBM Text Products

Missing Data:

For all Elements, a value of 999 indicates missing data. If data are missing for all forecast hours, the line for that element will not be printed.

Temperature and Dew Point

X / N (or N/X) 24-hour max / min (or min / max) temperature degrees F  
TMP temperature degrees F temperature at 2 meter height, valid at forecast time
DPT dew point temperature degrees F temperature to which air must be cooled for saturation to occur at 2 meter height, valid at forecast time

Sky Cover

SKY sky cover percent percent of the sky with opaque cover at the forecast time

Wind Speed and Direction 

WDR wind direction nearest tens degrees mean wind direction at 10 meters
WSP wind speed knots mean wind speed at 10 meters
GST wind gust knots maximum wind speed at 10 meters
Note: wind speeds of less than 0.5 knots will be listed as 0 (calm). For wind direction, northerly=36, easterly=9, calm=00.

Precipitation (PoP and QPF)

Probability of Precipitation (PoP) forecasts the probability that a threshold amount (usually the equivalent of 0.01 inches) of precipitation will fall during a time period, while the Quantitative Precipitation Forecast (QPF) predicts the amount of liquid-equivalent precipitation expected to fall over a time period. For NBM products, this time period is a number of hours before the specified forecast time. (i.e. PoP12 valid at 12Z is the probability there will be precipitation from 00:00Z-11:59Z of that day; PoP12 valid at 00Z is the probability there will be precipitation from 12:00Z-23:59Z of the previous day. Note that for the NBM text products all dates/times are in UTC/Z time.)

Probability of Precipiation (PoP)

P01 1-hour PoP percent probability at least 0.01 inches of rain (or the equivalent amount of snow, ice, etc.) will fall over the area from 1 hour before up until the forecast valid time.
P06 6-hour PoP percent probability at least 0.01 inches of rain (or the equivalent amount of snow, ice, etc.) will fall over the area from 6 hours before up until the forecast valid time.
P12 12-hour PoP percent probability at least 0.01 inches of rain (or the equivalent amount of snow, ice, etc.) will fall over the area from 12 hours before up until the forecast valid time.

Quantitative precipitation forecast (QPF)

Q01 1-hour QPF 1/100 inches the amount of rain (or the equivalent amount of snow, ice, etc.) expected to fall over the area from 1 hour before up until the forecast valid time.
Q06 6-hour QPF 1/100 inches the amount of rain (or the equivalent amount of snow, ice, etc.) expected to fall over the area from 6 hours before up until the forecast valid time.
Q12 12-hour QPF 1/100 inches the amount of rain (or the equivalent amount of snow, ice, etc.) expected to fall over the area from 12 hours before up until the forecast valid time.
Q24 24-hour QPF 1/100 inches the amount of rain (or the equivalent amount of snow, ice, etc.) expected to fall over the area from 24 hours before up until the forecast valid time.
Note: expected precipitation more than 9.98 inches will be listed as 998 in the text bulletin

Thunderstorms and Lightning

T01 1-hour thunderstorm/lightning probability percent
T03 3-hour thunderstorm probability percent
T12 12-hour thunderstorm probability percent

Weather Type Probabilities 

These are probabilities that precipitation is to fall as a specific type (if it is going to occur at all). Each precipitation type probability is calculated independently according to the forecast conditions, so that it is possible for 100% probability to occur in more than one category at the same time.  (These times represent conditions favorable for mixed precipitation). This is different than previous weather type probabilities produced by MOS and LAMP bulletins. 

PZR conditional probability of freezing rain percent probability that if precipitation occurs, it will fall in the form of freezing rain
PSN conditional probability of snow percent probability that if precipitation occurs, it will fall in the form of snow grains or pure snow
PPL conditional probability of sleet / ice pellets percent probability that if precipitation occurs, it will fall in the form of sleet or ice pellets
PRA conditional probability of rain percent probability that if precipitation occurs, it will fall in the form of rain

Snow and Ice

Snow Amounts

S01 1-hour snow amount 1/10 inches
S06 6-hour snow amount 1/10 inches
S12 12-hour snow amount 1/10 inches
S24 24-hour snow amount 1/10 inches

Snow Level

SLV snow level 100s feet MSL

Ice Amounts

I01 1-hour ice amount 1/100 inches
I06 6-hour ice amount 1/100 inches
I12 12-hour ice amount 1/100 inches
More than 99.8 inches of snow or 9.98 inches ice will be listed as 998

Ceiling and Visibility

VIS visibility miles
CIG ceiling height 100s feet
LCB lowest cloud base 100s feet

Note: Ceiling = 888 if unlimited

Note: CIG and LCB greater than 5000 feet are reported to the nearest 1000 feet

Marine

SWH significant wave height feet