A cold front will become banked up against the east slopes of the mountains today. Cool and moist air will spread into the plains today with thunderstorms developing first over the mountains, spreading onto the plains in the afternoon. Any of the thunderstorms could produce dangerous lightning and locally heavy rainfall. A few of the stronger storms could have hail around an inch in diameter. High temperatures today will be cooler than seasonal normal. On Monday...the best chance for thunderstorms will be over the mountains and adjacent terrain. Temperatures will be warmer, but still at or slightly below seasonal normal. (Please visit http://weather.gov/pub for more information.)