The "Forecast Performance" image allows the user to review the accuracy of the previous hour's forecast. The dark bown shapes are the 0350 GMT 1 hour forecast. These polygons are overlaid on the hazard field generated at 0450 GMT. A perfect forecast would have the polygons filled with level 3 or higher and only level 1 & level 2 outside the polygons. Click image to toggle to the 0350 hazard field and forecast shapes.  

Click "Smoothing forecast shape" to return to forecast to this forecast section.