This is calculated after the fact. The contours and intensity of the colors indicate the amount of precipitation forecast for the 3 hour period ending at the valid time for the forecast. The amounts are liquid water equivalents . Depths of sleet and ice will more closely match their liquid water equivalents. The streamlines show the instantaneous flow of air, and do not necessarily indicate the exact trajectory of air parcels, since the wind field fluctuates and evolves over time.
Wind speed is indicated by the darkness of the streamline.
Colors progress from light grey to black in increments of 5 kts with black indicating winds of 30 kts or more. Temperatures are in degrees Fahrenheit. Contour interval is 5 degrees. Multiples of 10 have black contours and are labeled. Pressure is in millibars.