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Interpreting the NAM Model




 
                                   Sample Message

          KDCA   NAM MOS GUIDANCE    1/26/2005  1200 UTC                
          DT /JAN  24/JAN  25                /JAN  26                /JAN  27  
          HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12
          N/X                    15          24          20          30    28
          TMP  36 35 30 24 21 18 16 21 23 22 23 21 20 21 22 24 27 29 29 29 30
          DPT  14  9  3  0 -2 -4 -3 -3 -2  2  8 12 15 17 19 22 24 25 25 24 21
          CLD  CL CL FW FW SC SC BK OV OV OV OV OV OV OV OV OV OV OV OV BK FW
          WDR  34 33 34 35 34 36 36 06 14 08 05 04 02 02 03 05 05 06 03 35 34
          WSP  07 14 14 11 10 10 08 03 02 05 07 11 11 12 10 07 04 04 07 11 10
          P06         0     0     0     0    55    76    60    34    36 13  9
          P12                     0          58          86          48    25
          Q06         0     0     0     0     1     1     1     0     1     0
          Q12                     0           1           2           1     0
          T06      0/ 0  0/ 9  0/ 1  1/ 0  3/ 0  0/ 0  0/ 1  0/ 0  3/ 0  0/ 0
          T12            1/ 9        1/ 1        3/ 0        1/ 1     1/ 0  
          SNW                     0                       6                 0
          CIG   6  8  8  8  8  7  7  7  7  4  4  3  2  3  3  2  2  1  1  2  8 
         
          -------------------------------------------------------------------

          DT = The day of the month, denoted by the standard three or four 
               letter abbreviation 

          HR = Hour of the day in UTC time. This is the hour at which the 
               forecast is valid, or if the forecast is valid for a period, 
               the end of the forecast period. 

          N/X = daytime minimum/nightime maximum surface temperatures. 

          TMP = surface temperature valid at that hour. 

          DPT = surface dewpoint valid at that hour. 

          CLD = forecast categories of total sky cover valid at that hour. 

          WDR = forecasts of the 10-meter wind direction at the hour, given 
                in tens of degrees. 

          WSP = forecasts of the 10-meter wind speed at the hour, given in knots. 

          P06 = probability of precipitation (PoP) during a 6-h period ending 
                at that time. 

          P12 = PoP during a 12-h period ending at that time. 

          Q06 = quantitative precipitation forecast (QPF) category for liquid 
                equivalent precipitation amount during a 6-h period ending at 
                that time. 

          Q12 = QPF category for liquid equivalent precipitation amount during 
                a 12-h period ending at the indicated time. 

          T06 = probability of thunderstorms/conditional probability of severe
                thunderstorms during the 6-hr peri od ending at the indicated time. 

          T12 = probability of thunderstorms/conditional probability of severe 
                thunderstorms during the 12-hr per iod ending at the indicated time. 

          SNW = snow fall categorical forecasts during a 24-h period ending at 
                the indicated time. 
    
          CIG = ceiling height categorical forecasts at the hour. 


          Definitions of Categorical Elements

          MET QPF Categories 
          0  no precipitation 
          1  0.01 to 0.09 inches 
          2  0.10 to 0.24 inches 
          3  0.25 to 0.49 inches 
          4  0.50 to 0.99 inches 
          5  1.00 to 1.99 inches 
          6  2.00 inches or greater 


          MET Snow Fall Amount Categories 
          0  no snow or a trace expected 
          1  > a trace to < 2 inches  
          2  2 to < 4 inches  
          4  4 to < 6 inches  
          6  6 to < 8 inches  
          8  >= 8 inches  

          MET Cloud (CLD) Categories 
          CL  clear  
          FW  > 0 to 2 octas of total sky cover 
          SC  > 2 to 4 octas of total sky cover  
          BK  > 4 to < 8 octas of total sky cover 
          OV  8 octas of total sky cover or totally obscured 


          MET Ceiling Height (CLD) Categories 
          1  < 200 feet  
          2  200 - 400 feet  
          3  500 - 900 feet  
          4  1000 - 1900 feet 
          5  2000 - 3000 feet 
          6  3100 - 6500 feet 
          7  6600 - 12,000 feet 
          8  > 12,000 feet

          VISIBILITY CATEGORICAL DEFINITIONS:
	  1 = < ½ MI
	  2 = ½ MI TO < 1 MI
	  3 = 1 TO < 2 MI
	  4 = 2 TO < 3 MI
	  5 = 3 TO 5 MI
	  6 = 6 MI
	  7 = > 6 MI

          OBSTRUCTION TO VISION CATEGORICAL DEFINITIONS:
	  N = NONE OF THE FOLLOWING
	  HZ = HAZE... SMOKE... DUST
	  BR = MIST (FOG WITH VISIBILITY >= 5/8 MI)
	  FG = FOG OR GROUND FOG (VISIBILITY < 5/8 MI)
	  BL = BLOWING DUST... SAND... OR SNOW









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