Flash Flood Prediction Program

Message 1’s have been issued effective until 9pm as there is a threat of heavy rainfall this afternoon and into this evening.

A few moderate to strong storms have formed along the foothills and should begin moving into the District over the next hour or so. Multiple rounds of showers/thunderstorms will be possible with the last round likely tapering off by 9pm. The largest threat for storms today will be a quick 0.50-0.60” in 10-15 minutes, with a low threat for any rainfall over an inch as most storms move between 10-15mph. These SW to NE storm motions should help limit point rainfall amounts, however, a stronger storm has the potential to produce longer lasting moderate to heavy rainfall. A gust front from a strong storm could result in additional storm development with erratic or slower moving storm motions throughout the District.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce rainfall of a 0.05” to 0.25” total in 10-30 minutes. Moderate to strong showers/thunderstorms have the will produce rainfall of 0.25 to 0.75” total in 10-30 minutes.

WORST CASE SCENARIO: Strong stationery, or training of thunderstorms has the potential to produce 0.75” to 1.50” in under 60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 900 PM	100 PM TO 830 PM
Jefferson County	1	Current TO 900 PM	100 PM TO 830 PM
Broomfield County	1	Current TO 900 PM	100 PM TO 830 PM
Douglas County	1	Current TO 900 PM	100 PM TO 830 PM
Adams County	1	Current TO 900 PM	100 PM TO 830 PM
Denver County	1	Current TO 900 PM	100 PM TO 830 PM
DIA	1	Current TO 900 PM	100 PM TO 830 PM
Arapahoe County	1	Current TO 900 PM	100 PM TO 830 PM
the City of Aurora	1	Current TO 900 PM	100 PM TO 830 PM
Arvada	1	Current TO 900 PM	100 PM TO 830 PM
Wheat Ridge	1	Current TO 900 PM	100 PM TO 830 PM
Lakewood	1	Current TO 900 PM	100 PM TO 830 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 900 PM SUN	0.05" (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Arapahoe	Current TO 900 PM SUN	0.05" (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Boulder	Current TO 900 PM SUN	0.05" (90%) to 0.25" (50%) to 0.75" (30%)	ISSUED
Broomfield	Current TO 900 PM SUN	0.05" (85%) to 0.25" (45%) to 0.75" (25%)	ISSUED
Denver	Current TO 900 PM SUN	0.05" (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Douglas	Current TO 900 PM SUN	0.05" (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Jefferson	Current TO 900 PM SUN	0.05" (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM SUN	0.05" (100%) to 0.25" (75%) to 0.75" (50%)	ISSUED
Douglas	Current TO 900 PM SUN	0.05" (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Jefferson	Current TO 900 PM SUN	0.05" (90%) to 0.25" (60%) to 0.75" (30%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.