Flash Flood Prediction Program

-	Message 1's have been issued for the entire District and will be valid from noon until 9pm. Prime time for heavy rainfall producing thunderstorms is expected to be between 1-8pm. 1-2 rounds of thunderstorms are likely.
-	Thunderstorms are expected to begin to develop shortly over the foothills with chances increasing over the plains between 1-2pm. Strong thunderstorms will be capable of producing heavy rainfall that could lead to excessive runoff and possibly flash flooding. Storm motions from W to E at 15-20mph will help to keep the heavy rainfall relatively brief but large thunderstorms or slower moving thunderstorms may produce an extended period of heavy rainfall. Strong thunderstorms may also have a tendency to move more NW to SE in direction.
-	Strong thunderstorms may become severe producing large hail, gusty winds, and possibly even a very isolated tornado in tandem with heavy rainfall. Best chances for strong/severe thunderstorms at this time looks to be along/E of I-25 and in particular S over the Palmer Divide.

STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce 0.1-0.4" of rain in 10-30 minutes. Strong thunderstorms will have the potential to produce 0.4-1.2" in 10-30 minutes.

WORST CASE SCENARIO: A large thunderstorm or slower moving thunderstorm may produce up to 2.0" of rain in 30-60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Jefferson County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Broomfield County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Douglas County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Adams County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Denver County	1	1200 PM TO 900 PM	100 PM TO 800 PM
DIA	1	1200 PM TO 900 PM	100 PM TO 800 PM
Arapahoe County	1	1200 PM TO 900 PM	100 PM TO 800 PM
the City of Aurora	1	1200 PM TO 900 PM	100 PM TO 800 PM
Arvada	1	1200 PM TO 900 PM	100 PM TO 800 PM
Wheat Ridge	1	1200 PM TO 900 PM	100 PM TO 800 PM
Lakewood	1	1200 PM TO 900 PM	100 PM TO 800 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	100 PM TO 900 PM	0.1" (80%) to 0.4" (60%) to 1.2" (25%)	ISSUED
Arapahoe	100 PM TO 900 PM	0.1" (90%) to 0.4" (60%) to 1.2" (25%)	ISSUED
Boulder	100 PM TO 900 PM	0.1" (80%) to 0.4" (60%) to 1.2" (20%)	ISSUED
Broomfield	100 PM TO 900 PM	0.1" (80%) to 0.4" (60%) to 1.2" (20%)	ISSUED
Denver	100 PM TO 900 PM	0.1" (80%) to 0.4" (60%) to 1.2" (20%)	ISSUED
Douglas	100 PM TO 900 PM	0.1" (90%) to 0.4" (60%) to 1.2" (25%)	ISSUED
Jefferson	100 PM TO 900 PM	0.1" (90%) to 0.4" (60%) to 1.2" (25%)	ISSUED
Foothills above 6500ft
Boulder	1200 PM TO 900 PM	0.1" (90%) to 0.4" (60%) to 1.2" (15%)	ISSUED
Douglas	1200 PM TO 900 PM	0.1" (90%) to 0.4" (60%) to 1.2" (25%)	ISSUED
Jefferson	1200 PM TO 900 PM	0.1" (90%) to 0.4" (60%) to 1.2" (20%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.