Flash Flood Prediction Program

-	Message 2's will become valid at 11:00am as thunderstorms that develop today will be very capable of producing heavy rainfall that may lead to excessive runoff and possibly flash flooding. Multiple rounds of strong thunderstorms are expected through the afternoon and evening.
-	Thunderstorms will first develop over the foothills and Palmer Divide by 11am to noon. Thunderstorms will begin to move onto the plains between 1-2pm. Training of thunderstorm cells or large slower moving thunderstorms will be the main culprits for extended periods of heavy rainfall. Upper level steering winds are light from W/WSW to E/ENE at 10-15mph. Roadways/smaller creeks and streams will be most prone to excessive runoff/flooding today.
-	Prime time for strong thunderstorms over the plains is from 1-9pm. After 9 or 10pm the thunderstorm activity is expected to have pushed east of the District with lingering light rain showers possible into the evening.

STORM RAINFALL POTENTIAL AND DURATION: Weak thunderstorms will produce 0.2-0.6" of rain in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce heavy rainfall rates of 0.6-1.8" in 10-30 minutes

WORST CASE SCENARIO: Training of thunderstorm cells or a large slow moving strong thunderstorm may result in very heavy rainfall of up to 4.0" in 60-90 minutes. Should rain continue for longer than 90 minutes in duration higher amounts are possible.

County	Message	Valid Times	Prime Time
Boulder County	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Jefferson County	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Broomfield County	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Douglas County	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Adams County	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Denver County	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
DIA	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Arapahoe County	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
the City of Aurora	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Arvada	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Wheat Ridge	2	1100 AM TO 1159 PM	1100 AM TO 900 PM
Lakewood	2	1100 AM TO 1159 PM	1100 AM TO 900 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	1200 PM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Arapahoe	1200 PM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Boulder	1200 PM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Broomfield	1200 PM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Denver	1200 PM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Douglas	1200 PM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Jefferson	1200 PM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Foothills above 6500ft
Boulder	1100 AM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Douglas	1100 AM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED
Jefferson	1100 AM TO 1159 PM	0.3" (95%) to 0.9" (60%) to 1.8" (30%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.