42 MANUAL OF MARINE METEOROLOGICAL OBSERVATIONS 



at the back of this manual) lists 100 weather situations, numbered from 00 to 

 99, which includes one or more of the weather elements discussed in the 

 first portion of this chapter. 



5720. CODING. Select the number from Code Table 6 (listed at the 

 back of this manual, or from WB Form 615-5) that corresponds most 

 nearly to the weather occurring at the time of the observation, or within 1 

 hour preceding the time of the observation. When precipitation is not occur- 

 ring at the ship at the time of observation, the selection of "ww" should be 

 made from code figures 00 to 49, and 98.^ When precipitation is occurring 

 at the time of the observation, the selection should be made from figures 50 

 to 99, inclusive. 



5730. ENTRY OF PRESENT WEATHER DATA ON FORM 615-5. The 

 code number selected as best representing the present weather (ww) should 

 be entered in column 11 of Form 615-5. If more than one code number 

 appears to be required, the highest should be entered in column 11, and all 

 other appropriate numbers entered in the column headed "Remarks." 



5731. Whenever fog is encountered, enter the character of the fog as 

 "slight," "heavy," "shallow," or "ice fog," and the time (GCT) of beginning 

 and ending in the column headed "Remarks" of WB Form 615-5. 



5732. Enter the time (GCT) of beginning and ending of precipitation in 

 the column headed "Remarks." 



5800. PAST WEATHER (W) 



5810. GENERAL. The term "past weather" refers to the state of the 

 weather during the 6-hour interval prior to the time of the 00, 06, 12, and 

 18 GCT observations. However, when the ship is in the vicinity of a tropical 

 storm, the Weather Bureau may request additional observations at 03, 09, 

 15, and 21 GCT (see J1021). For these extra observations, "past weather" 

 refers to the state of the weather during the 3-hour interval prior to the 

 time of the observation, and references in the following instructions to 6 

 hours will be understood, under these special circumstances, to refer to 

 3 hours. 



5820. CODING AND ENTRY OF PAST WEATHER DATA (W) ON FORM 

 615-5. Select the code figure from Code Table 7 listed on page 44 of this 

 manual, or from Table 7 on cover of Ship's Weather Observations, corre- 

 sponding to the weather during the preceding 6 hours, and enter it in column 

 12. To a certain extent, the combined data coded as "W" and 



When not accompanied by precipitation. 



