Flash Flood Prediction Program

Message 1’s will be allowed to expire at 8:00pm as the threat for heavy rainfall has ended. Cooler temperatures behind the initial wave of thunderstorms has lowered temperatures in to the 60’s and the atmosphere has stabilized.

There are a few lingering rain showers lurking to the W of the District that may pass through this evening but most areas will trend on the drier side from this point forward into the evening. Best chances for an additional light rain shower will be W of I-25 in or near the foothills. Dry conditions are expected all areas by around 10:00pm.

There is some great news though as the SW flow aloft behind the upper level disturbance has helped to scour out much of the smoke/haze and air quality has improved significantly from earlier today and this trend of better air quality will continue into tomorrow.

Lingering moisture and another upper level disturbance will result in afternoon thunderstorms on Thursday afternoon and the stronger storms will be capable of producing heavy rainfall which may result in another Message 1 day across the District if surface moisture remains elevated. Should surface moisture decrease Message 1's will be less likely tomorrow.

STORM RAINFALL POTENTIAL AND DURATION: Any additional isolated rain showers will only produce a trace to 0.10” of rainfall in areas that receive shower activity. Most areas will be dry from this point forward.

WORST CASE SCENARIO: Should a weak thunderstorm be able to develop rainfall rates of 0.1-0.3" in 10-30 minutes will be possible.

County	Message	Valid Times	Prime Time
Boulder County	1	1200 PM TO 800 PM	100 PM TO 700 PM
Jefferson County	1	1200 PM TO 800 PM	100 PM TO 700 PM
Broomfield County	1	1200 PM TO 800 PM	100 PM TO 700 PM
Douglas County	1	1200 PM TO 800 PM	100 PM TO 700 PM
Adams County	1	1200 PM TO 800 PM	100 PM TO 700 PM
Denver County	1	1200 PM TO 800 PM	100 PM TO 700 PM
DIA	1	1200 PM TO 800 PM	100 PM TO 700 PM
Arapahoe County	1	1200 PM TO 800 PM	100 PM TO 700 PM
the City of Aurora	1	1200 PM TO 800 PM	100 PM TO 700 PM
Arvada	1	1200 PM TO 800 PM	100 PM TO 700 PM
Wheat Ridge	1	1200 PM TO 800 PM	100 PM TO 700 PM
Lakewood	1	1200 PM TO 800 PM	100 PM TO 700 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 1000 PM WED	Trace (25%) to 0.05" (15%) to 0.1" (5%)	ISSUED
Arapahoe	Current TO 1000 PM WED	Trace (25%) to 0.05" (15%) to 0.1" (5%)	ISSUED
Boulder	Current TO 1000 PM WED	Trace (40%) to 0.05" (20%) to 0.1" (10%)	ISSUED
Broomfield	Current TO 1000 PM WED	Trace (30%) to 0.05" (20%) to 0.1" (5%)	ISSUED
Denver	Current TO 1000 PM WED	Trace (25%) to 0.05" (15%) to 0.1" (5%)	ISSUED
Douglas	Current TO 1000 PM WED	Trace (25%) to 0.05" (15%) to 0.1" (5%)	ISSUED
Jefferson	Current TO 1000 PM WED	Trace (40%) to 0.05" (20%) to 0.1" (10%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 1000 PM WED	Trace (60%) to 0.05" (30%) to 0.1" (15%)	ISSUED
Douglas	Current TO 1000 PM WED	Trace (30%) to 0.05" (20%) to 0.1" (10%)	ISSUED
Jefferson	Current TO 1000 PM WED	Trace (60%) to 0.05" (30%) to 0.1" (15%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.