Figure 3.8(a) 12-h accumulated precipitation (mm) and surface pressure (mb) valid at 00Z 4 September 2001 for runs using the Eta 10-km central nest are shown for the operational control (left) and the new grid-scale microphysics (right). A strong local maximum in precipitation is predicted over southwestern Texas in the control run along with a considerable amount of noise in the surface pressure field.

Figure 3.8(b) 24-h total precipitation (mm) and surface pressure from the operational control (left) and the new grid-scale microphysics (center) are compared with the 24-h total rainfall from the RFC analysis (right) valid at 12Z 4 September 2001. Too much rainfall is predicted over southwestern Texas in the control run.

Figure 3.8(c) Same as in (b), except for the 48-h forecast valid at 12Z 5 September 2001. A small precipitation bulls eye occurred in the operational control run near Galveston, TX, which was due to the grid-scale microphysics (not shown).