Flash Flood Prediction Program

Message 1’s have been issued for Adams, Arapahoe, Boulder, Broomfield and Denver Counties and will be valid until 8:00pm this evening.

Moisture has scoured out over S and SW areas of the District over Douglas and Jefferson Counties with higher moisture values over northern areas of the District. Northern areas of the District will have better chances for a stronger storm this afternoon and early evening. 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.

Best chances for thunderstorms will be over the next 3-4 hours then chances decrease after 7:00pm. 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 an outflow boundary from northern storms push back to the south and replenish surface moisture additional Message 1’s may be issued for Jefferson and Douglas Counties.

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
Broomfield County	1	Current TO 800 PM	Current TO 700 PM
Boulder County	1	Current TO 800 PM	Current TO 700 PM
DIA	1	Current TO 800 PM	Current TO 700 PM
Arapahoe County	1	Current TO 800 PM	Current TO 700 PM
the City of Aurora	1	Current TO 800 PM	Current TO 700 PM
Arvada	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
Denver County	1	Current TO 800 PM	Current TO 700 PM
Adams County	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" (70%) to 0.3" (30%) to 0.9" (10%)	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" (50%) to 0.3" (25%) to 0.9" (5%)	LOW
Jefferson	Current TO 800 PM SAT	0.1" (50%) to 0.3" (25%) to 0.9" (5%)	LOW
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%)	LOW
Jefferson	Current TO 800 PM SAT	0.1" (60%) to 0.3" (30%) to 0.9" (10%)	LOW

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.