RSAS model backgrounds

Analysis Variable                 Background computed from Eta 221
------------------------------    --------------------------------------

RSAS Sea-level Pressure (slp)     RSAS slp* [sfc P, elevation, 700mb T]

NWS Sea-level Pressure  (slp)     Pressure reduced to MSL

Altimeter               (alt)     alt* [sfc P, elevation]

Potential Temperature   (theta)   theta* [sfc P, 2m T]

U,V components of wind  (u,v)     10m (U,V)

Dewpoint Temperature    (dewpt)   dewpt* [2m RH (forced to 1-100), 2m T]

Dewpoint Depression     (dpd)     dpd* [dewpt*, 2m T]; forced >= 0

3h Pressure Change      (Pt3)     Pt3* [alt* (t)-alt* (t-3)]



Notes
-----

- "*"'s indicate backgrounds derived from Eta output grids.  
  Grids used in the derivation are enclosed in brackets.  
  Backgrounds without "*"'s are ingested directly from Eta outputs.