COMPUTER PRODUCTS FNMOC  provides  a  large  number  of  charts  for dissemination  to  shore  and  fleet  units.  These  include analysis   and   prognostic   charts   ranging   from subsurface oceanographic charts to depictions of the troposphere,  as  well  as  a  number  of  specialized charts.  A  complete  listing  of  the  these  charts  is contained in The  Numerical  Environmental  Products Manual,  volume  III  (Environmental   Products), FLENUMMETOCCENINST   3145.2. APPLICATION OF SATELLITE IMAGERY As a further aid, satellite imagery can also be used in  preparing  prognostic  charts.  The  availability  of useful satellite data will vary with time and area. OBJECTIVE  FORECASTING TECHNIQUES LEARNING  OBJECTIVES:  Evaluate  various objective  forecasting  techniques,  including extrapolation and   isotherm-contour relationships for the movement of troughs and ridges. Forecast intensity of troughs and ridges. Forecast  the  movement  of  upper  level  features. Forecast  the  intensity  of  upper  level  and associated  surface  features.  Lastly,  forecast  the formation of upper level and associated surface features. Experience in itself is not always enough to forecast the movement and/or intensity of upper air systems, but, couple  the  forecasters  experience  with  basic  objective techniques  and  a  more  accurate  product  will  be prepared. FORECASTING  THE  MOVEMENT  OF TROUGHS AND RIDGES Techniques covered in this section apply primarily to  long  waves. Some  of  the  techniques  will  be applicable to short waves as well. A long wave is by definition a wave in the major belt of westerlies, which is   characterized   by   large   length   and   significant amplitude. (See the  AG2 TRAMAN, volume 1, for a discussion of long and short waves.) Therefore, the first step in progging the movement and intensity of long waves is to determine their limits. There are several basic  approaches  to  the  progging  of  both  long  and short   waves.   Chiefly,   these   are   extrapolation, isotherm-contour relationship, and the location of the jet maximum in relation to the current in which it lies. Extrapolation The past history of systems affecting an area of interest is  fundamental  to  the  success  of  forecasting. Atmospheric  systems  usually  change  slowly,  but, continuously with time. That is, there is continuity in the weather patterns on a sequence of weather charts. When a particular pressure system or height center exhibits a tendency to continue without much change, it is said to be  persistent.  These  concepts  of  persistence and continuity are  fundamental  forecast  aids. The  extrapolation  procedures  used  in  forecasting may vary from simple extrapolation to the use of more complex  mathematical  equations  and  analog  methods based  on  theory.  The  forecaster  should  extrapolate  past and present conditions to obtain future conditions. Extrapolation is the simplest method of forecasting both long and short wave movement. Simple extrapolation is merely the movement of the trough or ridge to a future position based on past and current movement and expected trends. It is based on the  assumption  that  the  changes  in  speed  of  movement and  intensity  are  slow  and  gradual.  However,  it  should be noted that developments frequently occur that are not revealed  from  present  or  past  indications.  However,  if such  developments  can  be  forecast  by  other  techniques, allowances can be made. Extrapolation  for  short  periods  on  short  waves  is generally   valid. The   major   disadvantage   of extrapolating  the  long  period  movement  of  short  waves or long waves is that past and present trends do not continue indefinitely. This  can  be  seen  when  we consider a wave with a history of retrogression. The retrogression will not continue indefinitely, and we must look for indications of its reversal; that is, progressive movement. Isotherm-Contour  Relationships The forecaster should always examine the long waves  for  the  isotherm-contour  relationships,  and  then apply the rules for the movement of long waves. These rules are covered in the  AG2 TRAMAN,  volume  1. These rules are indicators only, but if they confirm or parallel other applied techniques, they have served their purpose. A number of observations and rules are stated regarding  the  progression,  stationary  characteristics,  or 2-2