a. 850-mb geopotential height (meters, solid heavy
contour) and 500-mb geopotential height
(dekameters, dashed light contour).
b. 1000850-mb layer thickness (m) and layer
mean winds. Warmest areas have lightest shading
(greater thickness) and coolest areas have darkest
shading (smaller thickness).
Figure 13. Synoptic conditions for 12 UTC, 8 Nov.
1997. Data were derived from the initial analyses of
the U.S. National Meteorological Center (NMC) ETA
numerical forecast model.