Flash Flood Prediction Program

Message 1’s will be extended until 11:59pm for Arapahoe and Douglas County as the threat of heavy rainfall continues.

Message 1's will be allowed to expire at 11:00pm for ALL other areas of the District.

The late evening round of showers/thunderstorms slowed over the Denver metro this evening which has resulted in the extension of Message 1’s for southeastern portions of the District. Storms producing heavy rainfall have moved through Denver with some areas receiving up to 0.91” of rainfall in under 1 hour in western Arapahoe County. This line of storms has entered both Douglas and Arapahoe Counties and will impact the area over the next hour or so. Storms will likely bring 0.30-0.80” of rainfall for portions of Dougals and Arapahoe Counties.

A chance for off and on showers will persist through the overnight with any shower activity coming to an end between 2-3am. Skies will gradually clear through the rest of the overnight as lows decrease into the low to mid 60s. Very little overall chance for tomorrow with another chance for storms by midday, with similar NW to SE storm motions.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers/isolated thunderstorms will produce a 0.10-0.30” total in 10-30 minutes. A moderate to strong shower/thunderstorm will produce 0.30-0.80” total in 10-30 minutes.

WORST CASE SCENARIO: A strong thunderstorm, or training of thunderstorm cells has the potential to produce 0.80-1.40” in under 60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 1100 PM	Current TO 1100 PM
Jefferson County	1	Current TO 1100 PM	Current TO 1100 PM
Broomfield County	1	Current TO 1100 PM	Current TO 1100 PM
Douglas County	1	Current TO 1159 PM	Current TO 1130 PM
Adams County	1	Current TO 1100 PM	Current TO 1100 PM
Denver County	1	Current TO 1100 PM	Current TO 1100 PM
DIA	1	Current TO 1100 PM	Current TO 1100 PM
Arapahoe County	1	Current TO 1159 PM	Current TO 1130 PM
the City of Aurora	1	Current TO 1100 PM	Current TO 1100 PM
Arvada	1	Current TO 1100 PM	Current TO 1100 PM
Wheat Ridge	1	Current TO 1100 PM	Current TO 1100 PM
Lakewood	1	Current TO 1100 PM	Current TO 1100 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 1159 PM SUN	0.1" (20%) to 0.3" (10%) to 0.8" (5%)	NONE
Arapahoe	Current TO 1159 PM SUN	0.1" (60%) to 0.3" (30%) to 0.8" (15%)	ISSUED
Boulder	Current TO 1159 PM SUN	0.1" (10%) to 0.3" (5%) to 0.8" (0%)	NONE
Broomfield	Current TO 1159 PM SUN	0.1" (10%) to 0.3" (5%) to 0.8" (0%)	NONE
Denver	Current TO 1159 PM SUN	0.1" (30%) to 0.3" (15%) to 0.8" (5%)	NONE
Douglas	Current TO 1159 PM SUN	0.1" (60%) to 0.3" (30%) to 0.8" (15%)	ISSUED
Jefferson	Current TO 1159 PM SUN	0.1" (10%) to 0.3" (5%) to 0.8" (0%)	NONE
Foothills above 6500ft
Boulder	Current TO 1159 PM SUN	0.1" (10%) to 0.3" (5%) to 0.8" (0%)	NONE
Douglas	Current TO 1159 PM SUN	0.1" (50%) to 0.3" (25%) to 0.8" (10%)	ISSUED
Jefferson	Current TO 1159 PM SUN	0.1" (10%) to 0.3" (5%) to 0.8" (0%)	NONE

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.