Flash Flood Prediction Program

Message 1’s have been issued for the entire District effective until 9pm.

A few isolated storms have formed along the higher terrain west of the District and will move through the District over the next several hours before storm chances taper off after sundown. A boundary has also been set up along the eastern portion of the District which will likely be the focal point for stronger storm development heading into the evening with the potential some of the storms become severe. These severe storms will have strong winds, 60+ mph, hail up to 1.5".

The best chance for storms will be from now through 8pm with a few lingering showers through 9pm. Storm motions will typically be from west to east between 15-20mph, which should help limit point rainfall amounts. However, storms that form along outflow boundaries have the potential to stall out and bring moderate to heavy rainfall for an extended period of time. These storms will likely have the best chance of heavy rainfall leading to LOW IMPACT FLOODING with both threats of a quick 0.5” in 10-15 minutes, and a chance for rainfall over 1” in some spots, favoring eastern portions of the District at this time.

STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers, weak thunderstorms will produce a 0.10-0.50” total in 10-30 minute. A moderate to strong thunderstorm will produce 0.50-1.50” total in 10-30 minutes.

WORST CASE SCENARIO: A strong, anchored thunderstorm will have the potential to produce 2.50” in 60-75 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 900 PM	Current TO 830 PM
Jefferson County	1	Current TO 900 PM	Current TO 830 PM
Broomfield County	1	Current TO 900 PM	Current TO 830 PM
Douglas County	1	Current TO 900 PM	Current TO 830 PM
Adams County	1	Current TO 900 PM	Current TO 830 PM
Denver County	1	Current TO 900 PM	Current TO 830 PM
DIA	1	Current TO 900 PM	Current TO 830 PM
Arapahoe County	1	Current TO 900 PM	Current TO 830 PM
the City of Aurora	1	Current TO 900 PM	Current TO 830 PM
Arvada	1	Current TO 900 PM	Current TO 830 PM
Wheat Ridge	1	Current TO 900 PM	Current TO 830 PM
Lakewood	1	Current TO 900 PM	Current TO 830 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Arapahoe	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Boulder	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Broomfield	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Denver	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Douglas	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Jefferson	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Douglas	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED
Jefferson	Current TO 900 PM SAT	0.1" (75%) to 0.5" (50%) to 1.5" (25%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.