Help! How to get the weather information of a point plot?

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Dear all,
Is there any way to get the weather value of one point plot using GrADS?
For example:
I set the longitude -90, latitude 46 (that will be a point), there are
some weather parameter (such as u-wind, air temperature, etc) defined
in the control file. How can I get these weather value(wind air
temperature) of this point? so that these value can be called by
another program (such as a Java application)
Thanks in advance
harry