THREE-DIMENSIONAL HUMIDITY ANALYSIS

Figure 4-20.-Surface fronts, areas of continuous precipitation, areas covered by 8/8 middle clouds, and isolines of 500-hPa dewpoint depression at 0300 UTC, 7 September 1995. precipitation, and also of the larger areas of overcast compared and, by cross-checking, each can be middle clouds. completed with greater accuracy than if they were done Since the 500-hPa level dewpoint depression independently. analysis agrees well with the surface analysis of middle cloud and precipitation, the possibility exists of THREE-DIMENSIONAL HUMIDITY ANALYSIS—THE MOIST LAYER replacing or supplementing one of these analyses with the other. Using a single level (for example, the 500-hPa level The characteristics of the 500-hPa level dewpoint dewpoint depression analysis) to find probable cloud depression analysis, outlined above, make it a valuable areas does not indicate clouds above or below that level. adjunct to the surface analysis. These analyses can be For example, if the top of a cloud system reached only 4-18