All amended forecasts will use the time the forecast is amended as the beginning time, and the standard time of the forecast period as the ending time. For example, if the 281515 TAF is amended at 281700, it would be encoded 281715. The abbreviation "AMD" is used to indicate  an  amended  TAF.  The  abbreviation  "RTD" indicates  a  routine  delay,  and  "COR"  indicates  a corrected  TAF.  Specific  meteorological  elements  of  the TAF code are as follows: 1.  Element  dddffGf_mf_mKT  is  the  surface  wind direction to the nearest 10 degrees, and the wind speed in knots. Gusts are also included when applicable. The contraction "VRB" may be used for direction when the average wind speed is 6 knots or less. Calm winds are encoded as "00000KT." 2.  Element  VVVV  is  the  prevailing  visibility  in meters, rounded down to the nearest reportable value. Reportable  values  are  identical  with  those  in  NAV- METOCCOMINST 3141.2, Surface METAR Observa- tions  User’s  Manual.  Weather  and/or  obstructions  to vision  must  be  included  whenever  the  prevailing visibility is forecast to be 9000 meters (6 SM) or less. 3.  Element  w'w'  includes  the  forecast  weather and  obstructions  to  vision  using  the  standard abbreviations  as  outlined  in  NAVMETOCCOMINST 3141.2  and  NAVMETOCCOMINST  3144.1,  United States   Navy   Manual   for   Ship’s   Surface   Weather Observations. 4.   Element N_sN_sN_sh_sh_sh_s is the sky cover group using  standard  abbreviations  (i.e.,  SCT,  FEW,  etc.). Heights   are   reported   in   hundreds   of   feet   AGL   in accordance  with  NAVMETOCCOMINST  3141.2  and NAVMETOCCOMINST  3144.1.  This  group  is reported as often as necessary to indicateall forecast sky cover layers up to the forecast overcast (8/8) layer. The summation  principle  used  in  the  METAR  code  also applies   to   the   TAF   code.   Groups   are   reported   in ascending  order.  Clear  skies  are  reported  as  "SKC." Types of clouds are not encoded with the exception of cumulonimbus clouds. which are always reported as a separate  group  using  the  abbreviation  CB.  For example,  3/8  cumulonimbus  clouds  at  2,500  feet  would be encoded as SCT025CB. Partial obscurations are considered as the first layer in the sky cover group (i.e., fog forecast to cover 2/8 of the  station  would  be  encoded  as  SCT000).  Total obscurations are reported using the VVh_sh_sh_s group as p e r    N A V M E T O C C O M I N S T    3 1 4 1 . 2    a n d NAVMETOCCOMINST  3144.1. 5.  The  element  WSh_wsh_wsh_ws/dddffKT  or WSCONDS   is   the   non-convective,   low-level   wind shear  (LLWS)  group.     This  group  is  used  only  to forecast  wind  shear  not  associated  with  convective activity from the surface to 2,000 feet. The abbreviation WS  is  the  LLWS  indicator,  and  h_wsh_wsh_ws  is  the forecast  height  of  the  wind  shear  in  hundreds  of  feet AGL. The contraction WSCONDS indicates that wind shear conditions are present but complete information cannot be reliably forecast. 6.   The element 6I_ch_ih_ih_it_L is the icing group (not associated  with  thunderstorms).  The  number  6  is  the icing  indicator  and  I_c  represents  the  type  of  icing,  as encoded  from  table  3-2.  The  h_ih_ih_i  is  the  icing  layer base  in  hundreds  of  feet  AGL.  The  t_L  represents  the thickness  of  the  icing  layer  in  thousands  of  feet,  as encoded  from  table  3-3.  Example:  650203  indicates moderate icing in cloud from 2,000 to 5,000 feet. 7.  Element  5Bh_bh_bh_bt_L  is  the  turbulence  group (not associated with thunderstorms). The number 5 is the  turbulence  indicator  and  the  letter  "B"  is  the turbulence type and intensity encoded from table 3-4. Extreme  turbulence  is  encoded  with  an  "X."  The h_bh_bh_b  is  the  forecast  height  of  the  turbulence  in hundreds  of  feet  AGL.  The  t_L  is  the  thickness  of  the turbulence layer in thousands of feet AGL, as encoded from table 3-3. Example: 561205 indicates occasional severe  turbulence  in  clear  air  from  12,000  to  17,000 feet. Table 3-2.—Icing Type (I_c) I_c = Type of forecast ice accretion on external parts of aircraft Code Figure 0 No Icing 1 Light Icing 2 Light Icing in Cloud 3 Light Icing in Precipitation 4 Moderate Icing 5 Moderate Icing in Cloud 6 Moderate Icing in Precipitation 7 Severe Icing 8 Severe Icing in Cloud 9          Severe Icing in Precipitation 3-2