Sea-level pressure (black contours every 4 hPa), 1000-500 hPa thickness (solid contours every 6 dam; blue at 540 dam and below; red above 540 dam), wind speed on the dynamic tropopause (shaded in m s-1; green=30, yellow=40, orange=50, red=60, pink=70), and total column precipitable water (grayscale shading in mm).
These plots are derived from the NCEP GFS analyses and forecasts on a 0.25x0.25o latitude-longitude grid. The dynamic tropopause is defined as the 2.0 PVU surface.