Flash Flood Prediction Program

-	Message 1's have been issued for the entire District and will be valid until 8:00pm this evening.
-	Moderate to strong, fast moving thunderstorms have developed north and northwest of the District at this time. Although fast moving, isolated areas of heavy rain will be possible under stronger cells. Thunderstorms will move from N/NW to E/SE at 20-25 mph.
-	The first round of storms will have the greatest potential to produce heavy rainfall with any subsequent rounds favoring light to brief moderate rain. Greatest threat for extended periods of heavy rainfall will be from training of thunderstorm cells or slower moving large thunderstorms.

STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce TR-0.3" in 10-30 minutes. Strong thunderstorms will have the potential to produce 0.3-0.8" of heavy rain in 10-30minutes. Supplemental QPF is available at https://qpf.udfcd.org

WORST CASE SCENARIO: A very large or slower moving thunderstorm may produce up to 1.6" of rain in 45-60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 800 PM	Current TO 700 PM
Jefferson County	1	Current TO 800 PM	Current TO 700 PM
Broomfield County	1	Current TO 800 PM	Current TO 700 PM
Douglas County	1	Current TO 800 PM	Current TO 700 PM
Adams County	1	Current TO 800 PM	Current TO 700 PM
Denver 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

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 800 PM THU	Trace (60%) to 0.3" (30%) to 0.8" (10%)	ISSUED
Arapahoe	Current TO 800 PM THU	Trace (60%) to 0.3" (30%) to 0.8" (10%)	ISSUED
Boulder	Current TO 800 PM THU	Trace (80%) to 0.3" (60%) to 0.8" (30%)	ISSUED
Broomfield	Current TO 800 PM THU	Trace (70%) to 0.3" (50%) to 0.8" (15%)	ISSUED
Denver	Current TO 800 PM THU	Trace (60%) to 0.3" (30%) to 0.8" (10%)	ISSUED
Douglas	Current TO 800 PM THU	Trace (60%) to 0.3" (30%) to 0.8" (10%)	ISSUED
Jefferson	Current TO 800 PM THU	Trace (80%) to 0.3" (60%) to 0.8" (30%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 800 PM THU	Trace (80%) to 0.3" (60%) to 0.8" (30%)	ISSUED
Douglas	Current TO 800 PM THU	Trace (80%) to 0.3" (60%) to 0.8" (30%)	ISSUED
Jefferson	Current TO 800 PM THU	Trace (80%) to 0.3" (60%) to 0.8" (30%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.