Flash Flood Prediction Program

Message 1’s have been issued effective until 9pm as there is a threat of heavy rainfall.

Storms have initiated along northern portions of the District today and will be moving quickly eastward through the afternoon and evening. Dew points at this time are not exceptionally high, in the upper 40’s to low 50’s. However, strong upper-level support is near the District, and out towards the eastern plains where strong to severe storms are likely.

Temperatures have remained fairly cool, although there is at least a chance for moderate to brief heavy rainfall within the District this afternoon and early evening. The best chance will be from now until 9pm with a few lingering storms through midnight tonight. A slight chance a storm could become severe inside the District, mainly for gusty winds and hail up to 1”. Storm motions will generally be from west to east between 15-25mph with some erratic storm movements possible along gust fronts. These storms will have the best chance of producing longer lasting heavy rainfall.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers/thunderstorms will produce a 0.05-0.25” total in 10 to 30 minutes. A moderate to strong thunderstorm will produce 0.25” to 0.50” total in 10 to 30 minutes. A strong to severe thunderstorm will produce 0.50” to 1.00” total in 10 to 30 minutes.

WORST CASE SCENARIO: An anchored strong thunderstorm or training of thunderstorm cells has the potential to produce up to 1.5” in under 60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 900 PM	Current TO 830 PM
Jefferson County	1	Current TO 900 PM	Current TO 830 PM
Broomfield County	1	Current TO 900 PM	Current TO 830 PM
Douglas County	1	Current TO 900 PM	Current TO 830 PM
Adams County	1	Current TO 900 PM	Current TO 830 PM
Denver County	1	Current TO 900 PM	Current TO 830 PM
DIA	1	Current TO 900 PM	Current TO 830 PM
Arapahoe County	1	Current TO 900 PM	Current TO 830 PM
the City of Aurora	1	Current TO 900 PM	Current TO 830 PM
Arvada	1	Current TO 900 PM	Current TO 830 PM
Wheat Ridge	1	Current TO 900 PM	Current TO 830 PM
Lakewood	1	Current TO 900 PM	Current TO 830 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Arapahoe	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Boulder	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Broomfield	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Denver	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Douglas	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Jefferson	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Douglas	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED
Jefferson	Current TO 900 PM SUN	0.05" (75%) to 0.25" (50%) to 0.5" (25%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.