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Darrell, GEMPAK uses the $GEMTBL/parms/pcconv.tbl table to define how to convert from the PTND (P03D) 3 hourly pressure tendency to P03C. There is no predefined 1 hour tendency- since its not a reported parameter, but you could use the PTND name. The key here is that PTND contains both the magnitude and tendency symbol in a single value for plotting the symbol in SFMAP as a symbol. P03C is just a numeric value for the change in millibars. If you just want to plot the numeric value, then any name like P01C would suffice. If you want the correct weather symbol for the change (rising, falling, falling rapidly, steady etc) then you have to use the known name. Steve Chiswell On Thu, 24 Aug 2000, Darrell Bryan Ensley wrote: > > Hi, Gembuds, > > I do not have 1-hr PMSL tendency in the surface dataset > that I'm working with, however, I could probably easily > calculate this in my fortran code. > > My question is how do i get this calculated 1-hr PMSL > tendency into GEMPAK...is there already a GEMPAK-accepted > 1-hr pressure tendency parameter, or can/do i need to > "create" one that GEMPAK will recognize. > > Am I making this too hard or what? > > Thanks! > > -Darrell > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Darrell Bryan Ensley <address@hidden> > Mesoscale Dynamics Lab 5703 Windlestraw Dr. > Rm 135, Research III Apartment 37 > North Carolina State Univ. Durham, NC 27713 > W: (919) 515-1437 H: (919) 361-1346 > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > >