Flash Flood Prediction Program

Message 1’s have been issued for the entire District effective until 8:00pm for the threat of heavy rainfall with a slight chance for severe storms across the District this afternoon and evening.

Storms have initiated along the higher terrain and are expected to move into the District over the next hour. Similar to yesterday storms will move from WSW to ENE between 10-15mph, with erratic storm movement likely along outflow boundaries. These outflow storms will likely have the highest potential for heavy rainfall today as they anchor in place. Storms may also contain large hail up to 1.0” and gusty winds up to 60mph. Dew points are also still elevated, in the mid to upper 50s and will likely help fuel moderate to heavy rainfall leading to some localized flooding.

A couple of rounds of storms will be possibly today, likely decreasing in strength as the evening progresses with off and on showers possible through the overnight. Overnight temperatures will drop to around 60 degrees on the plains with low to mid 50s along the foothills.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers and thunderstorms will produce a 0.10-0.50” total in 10-30 minutes. A moderate to strong shower/thunderstorm will produce 0.50-0.80" total in 10-30 minutes.

WORST CASE SCENARIO: Strong stationary thunderstorms, or training of thunderstorm cells could have the potential to produce up to 1.60” total in 30-60 minutes or less.

County	Message	Valid Times	Prime Time
Lakewood	1	Current TO 800 PM	Current TO 730 PM
Arvada	1	Current TO 800 PM	Current TO 730 PM
Wheat Ridge	1	Current TO 800 PM	Current TO 730 PM
Arapahoe County	1	Current TO 800 PM	Current TO 730 PM
the City of Aurora	1	Current TO 800 PM	Current TO 730 PM
DIA	1	Current TO 800 PM	Current TO 730 PM
Denver County	1	Current TO 800 PM	Current TO 730 PM
Adams County	1	Current TO 800 PM	Current TO 730 PM
Broomfield County	1	Current TO 800 PM	Current TO 730 PM
Douglas County	1	Current TO 800 PM	Current TO 730 PM
Jefferson County	1	Current TO 800 PM	Current TO 730 PM
Boulder County	1	Current TO 800 PM	Current TO 730 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 800 PM FRI	0.1" (80%) to 0.5" (60%) to 0.8" (30%)	ISSUED
Arapahoe	Current TO 800 PM FRI	0.1" (80%) to 0.5" (60%) to 0.8" (30%)	ISSUED
Boulder	Current TO 800 PM FRI	0.1" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Broomfield	Current TO 800 PM FRI	0.1" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Denver	Current TO 800 PM FRI	0.1" (80%) to 0.5" (60%) to 0.8" (30%)	ISSUED
Douglas	Current TO 800 PM FRI	0.1" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Jefferson	Current TO 800 PM FRI	0.1" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 800 PM FRI	0.1" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Douglas	Current TO 800 PM FRI	0.1" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED
Jefferson	Current TO 800 PM FRI	0.1" (75%) to 0.5" (50%) to 0.8" (25%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.