How to Read a Point Forecast


The NFDRS Point Forecast Format is as follows:

FCST,SSCCNN,YYMMDD,VT,W,TT,RH,L1,L2,DD,VV,M,TM,TN,HM,HN,P1,P2,WF
(commas but NO spaces between elements!)

If a forecast element is not forecast or unavailable, the "slot" where that element would usually be located is just followed by a comma, leading into the next element. There is no "space" or "M" for missing.

SSCCNN The six-digit station identifier
YYMMDD The valid day of the forecast
VT Valid time. Always a 13 for 1300 LST
W State of the weather at 1300 tomorrow (given by # below)
0 = less than 1/10 clouds 4 = fog 8 = showers
1 = 1/10 to 5/10 opaque 5 = drizzle 9 = thunderstorms
2 = 6/10 to 9/10 opaque 6 = rain
3 = cloudy 7 = snow/sleet
TT Temperature at 1300 tomorrow in F
RH Relative humidity at 1300 tomorrow
L1 Lightning activity level - 1300 today until midnight
(NO LONGER FORECAST...ALWAYS ENTER "1")
L2 Lightning activity level - midnight tonight til midnight tomorrow
(NO LONGER FORECAST...ALWAYS ENTER "1")
DD Wind direction (8 compass points) at 1300 tomorrow, i.e NW, E, SW
VV Wind speed (mph) at 1300 tomorrow
M 10 hour fuel moisture (input by users, leave as M)
TM max temp from 1300 today until 1300 tomorrow
TN min temp for tonight in F
HM Maximum humidity for tonight in percent
HN Minimum humidity for tomorrow in percent
P1 Hours of precipitation duration from 1300 today to 0500 tomorrow
P2 Hours of precipitation duration from 0500 tomorrow to 1300 tomorrow
WF Wet Flag. A "Y" or "N". It is used to indicate if fuels will be wet at 1300 tomorrow. All indicies will be set to zero if a Y is used. Thus use caution if forecasting a Y.

# = Use caution when using 5, 6, or 7 when forecasting state of the weather. Using these values assumes widespread precipitation and wet fuels at observation time. If in doubt, it is often better to forecast an 8, which assumes scattered precipitation.

EXAMPLE:

FCST,473901,990324,13,1,40,43,1,1,N,10,,43,20,81,36,0,0,N

Forecast for Black River Falls, valid for March 23, 1999. The forecast valid time is 1300 LST (1 pm CST, 2 pm CDT). Weather is expected to 1/10 to 5/10 cloud coverage, with a temperature of 40 degrees F and relative humidity of 43% at 1300 LST. Lightning activity level is not longer forecast, and 1's are entered in their place. The wind direction will be from the north with a speed of 10 mph at 1300 LST. Fuel moisture is not entered. The maximum temperature for tomorrow is expected to be 43, with a low temperature tonight of 20. The maximum relative humidty for night will be 81%, with a minimun tomorrow of 36%. No hours of precipitation expected from 1300 LST today through 0500 tomorrow. Also, no precipitation hours expected from 0500 LST tomorrow through 1300. Fuels are indicated to be "wet" tomorrow.



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