National Weather Service United States Department of Commerce
12-hour helicity forecast

 

Figure 7: ETA 12 Hour Forecast of 250-850 mb Qn vectors,
thickness and isotachs valid 1200 UTC May 12, 1997.

 

18-hour helicity forecast

 

Figure 8: ETA 18 Hour Forecast of 250-850 mb Qn vectors,
thickness and isotachs valid 1800 UTC May 12, 1997.