Flash Flood Prediction Program

-	Message 1's have been issued and will be valid from 12:00-9:00 PM.
-	Temperatures are rapidly warming and thunderstorms are beginning to develop over W and NW areas of the District. The storms are developing along a moist/dry line with and the initial storms of the day will favor the N and W areas of the District. These storms or additional storms over northern CO is expected to send a rain cooled outflow boundary southward which will help to trigger new storms as the afternoon progresses over other areas of the District.
-	Typical storms will move slowly from W to E with stronger storms possibly moving erratically or more slowly along surface wind convergence. Strong thunderstorms will have the potential to produce heavy rainfall as well as gusty winds and possibly hail.

STORM RAINFALL POTENTIAL AND DURATION: Weak thunderstorms will produce 0.1-0.4" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.4-1.2" in 10-30 minutes.

WORST CASE SCENARIO: Storms anchored to the foothills or surface boundary could produce up to 2.0" of heavy rain in 45-60 minutes.

County	Message	Valid Times	Prime Time
Lakewood	1	1200 PM TO 900 PM	100 PM TO 800 PM
Wheat Ridge	1	1200 PM TO 900 PM	100 PM TO 800 PM
Arvada	1	1200 PM TO 900 PM	100 PM TO 800 PM
the City of Aurora	1	1200 PM TO 900 PM	200 PM TO 800 PM
Arapahoe County	1	1200 PM TO 900 PM	200 PM TO 800 PM
DIA	1	1200 PM TO 900 PM	100 PM TO 800 PM
Denver County	1	1200 PM TO 900 PM	200 PM TO 800 PM
Adams County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Douglas County	1	1200 PM TO 900 PM	200 PM TO 800 PM
Broomfield County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Jefferson County	1	1200 PM TO 900 PM	100 PM TO 800 PM
Boulder County	1	1200 PM TO 900 PM	100 PM TO 800 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED
Arapahoe	100 PM TO 900 PM	0.1" (75%) to 0.4" (40%) to 1.0" (15%)	ISSUED
Denver	100 PM TO 900 PM	0.1" (75%) to 0.4" (40%) to 1.0" (15%)	ISSUED
Douglas	100 PM TO 900 PM	0.1" (75%) to 0.4" (40%) to 1.0" (15%)	ISSUED
Jefferson	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED
Boulder	Current TO 900 PM THU	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED
Broomfield	Current TO 900 PM THU	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED
Foothills above 6500ft
Douglas	100 PM TO 900 PM	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED
Boulder	Current TO 900 PM THU	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED
Jefferson	Current TO 900 PM THU	0.1" (80%) to 0.4" (50%) to 1.0" (20%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.