Flash Flood Prediction Program

Cooler temperatures have limited most storm development today. However, a stronger line of storms has initiated along the foothills this afternoon and will likely move into the District over the next hour or so. Dew points in the upper 50s to around 60, along with model driven PWAT values between 1.00-1.10” will result in efficient rainfall producing storms this afternoon and early evening. Currently storms will be moving from NW to SE around 15mph, with anchored storms possibly forming along outflow boundaries. These anchored/slow-moving storms will result in the potential for both 0.50” in 10-20 minutes and due to PWAT values above an inch, could result in an isolated 1.00-1.50” in under 60 minutes is storms linger, or there is training of storm cells. Once these rounds move out, skies will gradually clear through the late evening and overnight with temperatures dropping into the upper 50s for the plains with low to mid 50s along the foothills.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce a trace-0.25" total in 10-30 minutes. A moderate to strong thunderstorm will produce rainfall rates of 0.25”-0.75” total in 10- 30 minutes.

WORST CASE SCENARIO: A slow-moving thunderstorm, training of thunderstorms cells or a large thunderstorm complex may result in up to 1.50” of rain in 30-60 minutes.

County	Message	Valid Times	Prime Time
Lakewood	1	Current TO 900 PM	Current TO 830 PM
Wheat Ridge	1	Current TO 900 PM	Current TO 830 PM
Arvada	1	Current TO 900 PM	Current TO 830 PM
the City of Aurora	1	Current TO 900 PM	Current TO 830 PM
Arapahoe County	1	Current TO 900 PM	Current TO 830 PM
DIA	1	Current TO 900 PM	Current TO 830 PM
Denver County	1	Current TO 900 PM	Current TO 830 PM
Adams County	1	Current TO 900 PM	Current TO 830 PM
Douglas County	1	Current TO 900 PM	Current TO 830 PM
Broomfield County	1	Current TO 900 PM	Current TO 830 PM
Jefferson County	1	Current TO 900 PM	Current TO 830 PM
Boulder County	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 THU	Trace (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Arapahoe	Current TO 900 PM THU	Trace (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Boulder	Current TO 900 PM THU	Trace (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Broomfield	Current TO 900 PM THU	Trace (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Denver	Current TO 900 PM THU	Trace (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Douglas	Current TO 900 PM THU	Trace (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Jefferson	Current TO 900 PM THU	Trace (80%) to 0.25" (40%) to 0.75" (20%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM THU	Trace (80%) to 0.25" (50%) to 0.75" (30%)	ISSUED
Douglas	Current TO 900 PM THU	Trace (80%) to 0.25" (50%) to 0.75" (30%)	ISSUED
Jefferson	Current TO 900 PM THU	Trace (80%) to 0.25" (50%) to 0.75" (30%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.