The daily PNA index correpsponds to the PNA patterns, which vary from one month to the next. Click here for the methodology used to calculate the daily PNA index.

The daily PNA index for the past 120 days. Each daily value has been standardized by the standard deviation of the monthly PNA index from 1950 to 2000 interpolated to the day in question.

• Monthly mean PNA index since January 1950

• Monthly mean PNA index based on modified pointwise method

• Animations (circulations)

• GFS PNA outlooks
• Ensemble mean PNA outlooks

• Pacific/North American pattern (PNA)

Barnston, A. G., and R. E. Livezey, 1987: Classification, seasonality and persistence of low-frequency atmospheric circulation patterns. Mon. Wea. Rev., 115, 1083-1126.

Chen, W. Y., and H. van den Dool, 2003: Sensitivity of Teleconnection Patterns to the Sign of Their Primary Action Center, Mon. Wea. Rev., 131, 2885-2899.

van den Dool, H. M., S. Saha, and Å. Johansson, 2000: Empirical Orthogonal Teleconnections. J. Climate, 13, 1421-1435.