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Mohan, The ETA212 grids actually have a the U and V storm motion: 64 000406/1200F000 6000 0 HGHT VSTRM 65 000406/1200F000 6000 0 HGHT USTRM To create a vector from these 2 components, VECN(USTRM,VSTRM) Click on the "Vector" and "Layer" radio buttons in the Garp model selection and chose the 6000:0 lyer from the Height coordinate pop-up. If you want to specify your own storm motion vector using your own components, you can just enter their U & V magnitudes like: VECN(5,-5) One more way would be to use the VLAV(OBS) function to create an avarage wind over a layer as a way to specify a storm motion. Steve Chiswell Unidata User Support On Thu, 6 Apr 2000, Mohan Ramamurthy wrote: > Hi Chiz, > > How do I plot storm relative winds in GARP? I see that GEMPAK has a VSUB > function I could use and subtract out storm motion, but how do I specify > storm motion as a vector (which would be second argument for VSUB)? Thanks. > > Mohan > > > ---------------------------------------------------------------------------- > Dr. Mohan Ramamurthy Email: address@hidden > Associate Professor Ph: (217) 333-8650 > Department of Atmospheric Sciences Fax: (217) 244-4393 > University of Illinois at Urbana-Champaign > 105 S. Gregory Street > Urbana, IL 61801-3070 >