Flash Flood Prediction Program

Message 1’s now includes all areas of the District and will be valid until 8:00pm this evening.

Outflow boundaries from previous storms are pushing moisture back to the W and is increasing the surface moisture which will help fuel thunderstorms. Northern and eastern areas of the District still have better chances for a stronger storm this afternoon and early evening as the moisture is more abundant in this zone. Storms over the foothills are expected to be weaker than plains storms. Much like the past few days the stronger storms will be capable of producing hail as well as brief moderate to heavy rainfall that may lead to excessive runoff roadways. Most storms will be weak to moderate with just a slight chance for a stronger thunderstorm.

Best chances for thunderstorms will be over the next few hours then chances decrease after 7:30pm. Typical storms will move from SW to NE at around 20mph and the relatively fast storm motions will help to reduce point rainfall amounts. A large thunderstorm or a slower moving thunderstorm will be the culprits for extended periods of heavy rain should they develop.

STORM RAINFALL POTENTIAL AND DURATION: Weak thunderstorms will produce 0.1-0.3" of rain. Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.3-0.9” in 10-30 minutes.

WORST CASE SCENARIO: A slow moving strong thunderstorm or large thunderstorm cell may result in up to 1.5” of rain in 45-60 minutes

County	Message	Valid Times	Prime Time
Arvada	1	Current TO 800 PM	Current TO 700 PM
the City of Aurora	1	Current TO 800 PM	Current TO 700 PM
Arapahoe County	1	Current TO 800 PM	Current TO 700 PM
DIA	1	Current TO 800 PM	Current TO 700 PM
Denver County	1	Current TO 800 PM	Current TO 700 PM
Adams County	1	Current TO 800 PM	Current TO 700 PM
Douglas County	1	Current TO 800 PM	Current TO 700 PM
Broomfield County	1	Current TO 800 PM	Current TO 700 PM
Jefferson County	1	Current TO 800 PM	Current TO 700 PM
Boulder County	1	Current TO 800 PM	Current TO 700 PM
Wheat Ridge	1	Current TO 800 PM	Current TO 700 PM
Lakewood	1	Current TO 800 PM	Current TO 700 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 800 PM SAT	0.1" (80%) to 0.3" (40%) to 0.9" (20%)	ISSUED
Arapahoe	Current TO 800 PM SAT	0.1" (75%) to 0.3" (35%) to 0.9" (15%)	ISSUED
Boulder	Current TO 800 PM SAT	0.1" (85%) to 0.3" (50%) to 0.9" (25%)	ISSUED
Broomfield	Current TO 800 PM SAT	0.1" (85%) to 0.3" (50%) to 0.9" (25%)	ISSUED
Denver	Current TO 800 PM SAT	0.1" (80%) to 0.3" (40%) to 0.9" (20%)	ISSUED
Douglas	Current TO 800 PM SAT	0.1" (75%) to 0.3" (30%) to 0.9" (15%)	ISSUED
Jefferson	Current TO 800 PM SAT	0.1" (75%) to 0.3" (30%) to 0.9" (15%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 800 PM SAT	0.1" (60%) to 0.3" (30%) to 0.9" (10%)	ISSUED
Douglas	Current TO 800 PM SAT	0.1" (60%) to 0.3" (30%) to 0.9" (10%)	ISSUED
Jefferson	Current TO 800 PM SAT	0.1" (60%) to 0.3" (30%) to 0.9" (10%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.