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<\/a><\/p>\nThis afternoon’s water vapor imagery, below, shows a rather busy atmospheric pattern over the eastern North Pacific Ocean and western North American continent. A weak upper-level ridge was positioned over Alberta with an undercutting jet stream<\/span> to the south. Within this jet, several weak disturbances were noted, causing large-scale upward motion. As we move into the next 72-96 hours, these features will trek across Colorado, providing enhanced periods of generally light to moderate rainfall. The exception will be on Sunday, as a surface high pressure system is expected to drop south out of Canada, helping drive a cool front southward across eastern Colorado. A brief period of heavier rainfall will be possible, warranting an Elevated flood threat on Sunday afternoon and evening.<\/p>\n After Event #1, drier conditions are expected statewide as an upper-level ridge rebuilds to the northwest of Colorado. With a maintenance of average to above average Precipitation Water (PW<\/span>; see GFS ensemble plume forecasts below), isolated<\/span> showers and weak thunderstorms will be possible during the afternoons but the coverage and intensity appear to be too marginal to designate this as an individual precipitation “Event”. However, by Saturday, 9\/2, guidance is in reasonable agreement that a strong surface high pressure will move southward into the Great Plains out of Canada. This late in the season, it is uncertain whether there will be enough low-level moisture available for heavy rainfall, with even more uncertainty due to the presence of Hurricane Harvey in the Gulf of Mexico. However, we have labeled this as Event #2 due to an expected increase in precipitation coverage.<\/p>\n<\/a><\/p>\n