Figure 3.4(a) Mixing ratios (in g/kg) of cloud water (left), rain (center), and snow (right) at 750 mb valid at 12Z on 5 March 2001. Bold solid line is the 0C isotherm, dashed lines are for colder temperatures, and solid lines are for warmer temperatures. Note the presence of supercooled cloud water with snow in the Pacific Northwest, the Sierras, the mid Atlantic, and southern New England. A small amount of supercooled rain is seen over northern New Jersey and southern New York. The small area of supercooled rain along the Washington-Idaho border is a result of vertical interpolation from model coordinates to pressure coordinates.

Figure 3.4(b) Same as above except at 850 mb. The greater presence of rain, particularly along the west coast, is primarily due to the melting of snow falling from higher levels. An area of supercooled cloud water associated with a shallow, post-frontal cloud system formed by upslope flow over the Appalachian mountains. The small area of rain over West Virginia is likely due to the autoconversion of supercooled cloud water to rain.