Description:
The maps above show the monthly streamfunction climatology (grey contours) and anomalies standardized by the standard deviation for the given month 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 contour interval for the climatological streamfunction values is 10E+06 m2/s at 250 and 500 hPa and 5E+06 m2/s at 925 hPa. Dashed contours represent negative values, solid contours represent positive values. NCEP is an acronym for the U.S. National Centers for Environmental Prediction.