PRECIPITATION TOTAL.—6RRRt_R.     The RRR  is the liquid equivalent of the precipitation amount reported in hundreds, tens and units of millimeters (exception: 990 is a trace, and codes 991 to 999 are used to report tenths of a millimeter total precipitation from 0.1 to 0.9 respectively). And t_R is the duration of the reference period ending at the reporting time (WMO code table 4019). Precipitation amounts observed in inches may be converted to millimeters by multiplying 25.4 mm/inch. In WMO Regions IV and V, this group is normally  used  to  report  6-hour  precipitation  at  each synoptic  observation  with  t_R  encoded  1,  except  the 0000Z report from U.S. stations in Region V reports 24- hour precipitation with TV encoded 4. WEATHER.—7wwW₁W₂. The ww is the present weather code (WMO code table 4677), and W₁ and W₂ are past weather codes (WMO code table 4561). See appendix IV. PREDOMINANT   CLOUD   TYPE.— 8N_hC_LC_MC_H. The N_h is the summation coverage of all low etage clouds present, or, if no low clouds are present, the summation of all the mid-etage cloud coverage, in oktas of the sky covered (WMO code table 2700). C_L is the predominant low-etage cloud type (WMO code table 0513). C_M is the predominant mid- etage cloud type (WMO code table 0515). And C_H is the  predominant  high-etage  cloud  type  (WMO  code table  0509). OBSERVATION TIME.—9GGgg. This group is only encoded when the actual observation time (time the last element in the observation was observed) differs from  the  standard  observation  time  (the  synoptic  or intermediate synoptic hour) by 10 minutes or more. The GG is the UTC hour, while the gg is the minutes of the actual  observation  time. Q32. Q33. Q34. Q35. Q36. REVIEW  QUESTIONS What is the purpose of the Synoptic code? What are the intermediate synoptic hours? What is the primary reference manual used for encoding land synoptic observations in the United States? What groups are included in the identification section of a land synoptic observation? How would i_Ri_XhVV be encoded for a manned station  with  no  precipitation  or  significant weather in the past 6 hours, a low overcast cloud deck at 3,500 feet, and visibility at 7 miles? Q37. Q38. Q39. Q40. Q41. Q42. Q43. How would a station with 6/8 total sky coverage and a wind direction of 240° and a wind speed of 103 knots be encoded? What do the sections 1S_nTTT and 2S_nT_dT_dT_d indicate? What do the sections 3P_OP_OP_OP_O and 4PPPP indicate? If the station pressure at 0300Z was 1020.6 hPa, then increased to a high of 1021.5 hPa at 0400Z, and is now 1019.8 hPa at 0600Z, how should the group 5appp be encoded? If a station received 1.2 mm of precipitation between 0000Z and 0600Z, how should 6RRRt_r be  encoded? If a station had heavy snow showers at the time of observation and rain showers and overcast conditions in the previous 2 hours, how should the group 7wwW₁W₂ be encoded? If a station has no low clouds, 2/8 altocumulus castellanus,   3/8   thin   altostratus,   and   3/8 cirrostratus not covering the whole sky and not invading the celestial dome, how should the group   8N_hC_LC_H   be   encoded? Regional Data Section The regional data section, following the group 333, includes  both  internationally  established  codes  and codes unique to each region. WMO REGION IV STATE OF THE SKY IN THE TROPICS.—0C_SD_LD_MD_H. The C_S is the cloud state from FMH-2, table 6-4; while D_L, D_M, and D_H are the direction from which the low-, mid-, and high-etage clouds,  respectively,  are  moving  (using  the  8-point compass, 1 = NE, 2 = E, and so forth; 0 is no movement, and 9 is unknown). This group is only reported by stations in the southern portion of WMO Region IV within 310 statute miles of the seacoast during the tropical  season. MAXIMUM   TEMPERATURE.—1s_nT_XT_XT_X. The T_XT_XT_X is the maximum temperature in tens, units and tenths of a degree Celsius. The time period is specified by regional agreement; see table 3-6 for WMO Region IV and V conventions. MINIMUM TEMPERATURE.—2s_nT_nT_nT_n. The T_nT_nT_n is the minimum temperature in tens, units, and tenths of a degree Celsius. 3-14