Flash Flood Prediction Program

Message 1’s have been issued for the entire District and will be valid until 8:00 PM this evening.

Thunderstorms have developed along a boundary across the district and are slowly moving northeast due to weak upper level steering winds at 10mph or less. The slow motion of these storms may result in extended periods of heavy rainfall supporting excessive runoff and possibly flash flooding.

Best chances for thunderstorms will be through 7:00PM with light rain showers possible throughout the early evening. In addition, the ground remains saturated across the District and may not take as much rain as normal to produce runoff.

STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.3-0.8” in 10-30 minutes.

WORST CASE SCENARIO: A slow moving strong thunderstorm or nearly stationary thunderstorm may result in up to 1.4” of rain in 45-60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 800 PM	Current TO 700 PM
Jefferson County	1	Current TO 800 PM	Current TO 700 PM
Broomfield County	1	Current TO 800 PM	Current TO 700 PM
Douglas County	1	Current TO 800 PM	Current TO 700 PM
Adams County	1	Current TO 800 PM	Current TO 700 PM
Denver County	1	Current TO 800 PM	Current TO 700 PM
DIA	1	Current TO 800 PM	Current TO 700 PM
Arapahoe County	1	Current TO 800 PM	Current TO 700 PM
the City of Aurora	1	Current TO 800 PM	Current TO 700 PM
Arvada	1	Current TO 800 PM	Current TO 700 PM
Wheat Ridge	1	Current TO 800 PM	Current TO 700 PM
Lakewood	1	Current TO 800 PM	Current TO 700 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Arapahoe	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Boulder	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Broomfield	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Denver	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Douglas	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Jefferson	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Douglas	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Jefferson	Current TO 800 PM FRI	0.3" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.