Appendix A: Examples of Time-Series Charts:
"Cross-Over Charts" and Meteograms

The following time-series graphs show the close relationship between the modern computer generated meteogram and the earlier hand-plotted charts once used by military forecasters. Figures A-1 and A-1a display the original FOUS bulletins from which the "cross -over charts" were plotted. The bulletin date is 12Z on 18 January 2001, and the data for Omaha, Nebraska, and Washington, D.C., are plotted in Figures A-2 and A-3, respectively.

Figures A-4 and A-5 show the EMC meteograms from the ETA model for the same date, time, and locations as for A-2 and A-3 above.

Figures A-6 and A-7 show the AFWA MM5 model meteograms for the same date, time, and places as above.

The valid time for the cross-over charts extends from the zero hour forecast to 48 hours later. The much longer valid times on the meteograms enable the forecaster to detect weather changes later in the forecast cycle.