Models And Forecast Zig-Zagging A Bit

First - a beautiful Fall morning today on the University of Arizona campus and across Tucson metro (see top image).
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The NAM forecast model (and the WRF) have been zig-zagging some on whether there will be rainfall in the lower elevations of southern Arizona as the 500 mb cutoff moves inland, and across Arizona, the next two days. The model forecasts yesterday were keeping the rainfall mostly to the north - i.e., drier forecasts than previously with low POPs. The runs overnight and this morning have resumed forecasting some rainfall here in southeast Arizona, although heaviest amounts stay north and on high elevations. The middle graphic from NCAR RAP shows the 500 mb cutoff to be positioned, at 12 UTC, over the Pacific, west-southwest of San Diego. Thunderstorms are active over the LA basin and the southwest California mountains this morning. The bottom graphic shows this morning's NAM rainfall forecast for the 24-hours ending at 5 pm Thursday afternoon. The Univ. of Arizona Atmo run of the WRF-GFS model at midnight indicated that the Tucson metro area would experience showers, and perhaps a thunderstorm or two, during the late night Wednesday and early morning hours of Thursday. Again, as per the WRF, amounts aren't heavy, but the convective character of the rainfall is delineated better in the WRF, with much of the metro area receiving only a Trace to a 1/10", while there are several narrow bands of heavier rain amounts forecasted.
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We'll now watch to see how things evolve the next 48-hours with this interesting cutoff.