56 



MANUAL OF MARIN:E METEOROLOGICAL OBSERVATIONS 



6420. CHARACTERISTIC (a). Code Table 15 will be used to select the 

 appropriate code for the characteristic of the 3-hour pressure tendency. 

 The code value should be entered in column 26 of Form 615-5. It should 



be noted that if the pressure is the same as three hours ago (that is, 

 is coded 00), then "a" must be coded as 0, 4 or 5. 



Code Table 15 



'PP' 



