NAM 500-mb Height Trends
Displayed below are 6-h forecasts of 500-mb geopotential height from the most recent 00Z or 12Z NAM model run
(thick dark green contours) from F00-F84. To assist in visualizing model trends, forecasts from the NAM runs initialized
12 h and 24 h earlier are overlain at the same valid time. The thickness and darkness of the contours decreases
with the age of each model run. The user can select a difference field between the current NAM run and that from the NAM
run 12 h or 24 h ago. The difference is shaded according to the color scale at the bottom left.