Description:
The maps above show the seasonal geopotential height climatology (grey contours) and anomalies standardized by the standard deviation for the 3-month season shown, over the base period 1971-2000 at 250 (top), 500 (middle), and 925 hPa (bottom).  The shading for the anomalies starts at +/-1 standard deviation; the color contour interval is 0.5 s.d. Positive anomalies are shown in yellow and orange; negative anomalies in shades of blue. The climatology contour interval in the 250 and 500 hPa maps is 60 gpm, and in the 925 hPa map is 30 gpm. NCEP is an acronym for the U.S. National Centers for Environmental Prediction.