A PVOR calculation question

Hi again Steve..

I'm stumped again...

Is it at all possible to do a PVOR calculation, from raw data without having
THTE pre calculated in the gempak grid?

I can successfully generate thte values from raw data, and for a sample
layer

say for example in gdcntr

glevel=850
gfunc=thte(tmpc,pres,sub(tmpc,dpdk))       Note: I don't have dwpt in my
gempak file hence the sub

Now when I want to do a layer I can do: 

glevel=850:500
gfunc=thte(lav(pres),lav(tmpc),sub(lav(tmpc),lav(dpdk)))   that works o.k.

But when I try to do a pvor calc for a layer like 
glevel=850:500
gfunc=pvor( thte(lav(pres),lav(tmpc),sub(lav(tmpc),lav(dpdk))) ,wnd)
or
gfunc=pvor( thte(lav(pres),lav(tmpc),sub(lav(tmpc),lav(dpdk))) ,vlav(wnd))

I keep getting a message that THTELAVPLAVT in PVOR mus be read from grid
file..

Is there a way to do the PVOR calc for a layer from raw data in a script or
does it really have to be calculated?

Many thanks again..

Lewis Poulin