ETA SEA LEVEL PRESSURE/1000-500 THICKNESS FORECASTS VALID 12Z 1/25

36 HR ETA FCST FROM 00Z 1/24 24 HR ETA FCST FROM 12Z 1/24
18 HR ETA FCST FROM 18Z 1/24 12 HR ETA FCST FROM 00Z 1/25

The trend by the Eta to move the storm further to the west with each cycle is clearly shown. This dispels the myth that the model "missed" the occurrence of the storm altogether. The model knew that a major east coast storm would occur even 36 hours before the event; it simply tracked the storm too far off the coast. The minor differences between the 2 plots in the right column (forecasts 12 hours apart) that result in a difference of about 0.50" of precipitation in the Washington, DC area indicate how sensitive the precipitation forecast was to slight changes in track and intensity of the low pressure center.