Flash Flood Prediction Program

-	Message 1's have been issued for the entire District and will be valid until 9:00 PM this evening.
-	Thunderstorms are beginning to develop over the foothills currently with one to two rounds of thunderstorms expected to move through the District into the early evening. Thunderstorms today may become strong to severe producing heavy rainfall, large hail and gusty winds.
-	Storm motion will generally be from W to E at 20-25mph with stronger thunderstorms potentially moving slower and from a more NW to SE direction. The relatively fast storm motion will help to keep the heavy rain relatively brief, but excessive runoff may still occur under stronger thunderstorm cells.

STORM RAINFALL POTENTIAL AND DURATION: Typical weak to moderate thunderstorms will produce 0.1-0.4" of rainfall. Strong thunderstorms will have the potential to produce 0.4-1.0" in 10-30 minutes.

WORST CASE SCENARIO: A slow moving strong thunderstorm or training of thunderstorm cells may produce up to 2" of rain in 60 minutes or less.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 900 PM	130 PM TO 800 PM
Jefferson County	1	Current TO 900 PM	130 PM TO 800 PM
Broomfield County	1	Current TO 900 PM	130 PM TO 800 PM
Douglas County	1	Current TO 900 PM	130 PM TO 800 PM
Adams County	1	Current TO 900 PM	130 PM TO 800 PM
Denver County	1	Current TO 900 PM	130 PM TO 800 PM
DIA	1	Current TO 900 PM	130 PM TO 800 PM
Arapahoe County	1	Current TO 900 PM	130 PM TO 800 PM
the City of Aurora	1	Current TO 900 PM	130 PM TO 800 PM
Arvada	1	Current TO 900 PM	130 PM TO 800 PM
Wheat Ridge	1	Current TO 900 PM	130 PM TO 800 PM
Lakewood	1	Current TO 900 PM	130 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" (50%) to 1.0" (20%)	ISSUED
Arapahoe	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED
Boulder	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (15%)	ISSUED
Broomfield	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (15%)	ISSUED
Denver	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (15%)	ISSUED
Douglas	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (15%)	ISSUED
Jefferson	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (15%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM FRI	0.1" (80%) to 0.4" (50%) to 1.0" (10%)	ISSUED
Douglas	Current TO 900 PM FRI	0.1" (80%) to 0.4" (50%) to 1.0" (10%)	ISSUED
Jefferson	Current TO 900 PM FRI	0.1" (80%) to 0.4" (50%) to 1.0" (10%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.