Flash Flood Prediction Program

Message 1’s have been extended to 11:59pm as the threat of heavy rainfall remains over the District.

A gust front from the north stirred the pot at this late hour. These storms will likely pulse up and down over the District over the next couple of hours as they move west to east. Low to mid 50’s dew points, combined with an approaching trough of low-pressure, has resulted in good dynamics for late evening rain and thunderstorms.

A few pockets of rain will likely be heavy at times, with a chance of a quick 0.5” in 10 minutes likely being the largest threat. However, due to an already saturated surface even general showers will result in pooling of water and rising creeks/streams.

The best chance for storms will be from now through midnight with a few lingering off and on showers possible through daybreak tomorrow.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce a trace to 0.25” total, in 10-30 minutes. A weak to moderate thunderstorm will produce 0.25-0.75” total in 10-30 minutes.

WORST CASE SCENARIO: A stronger thunderstorm, or training of moderate showers/thunderstorms will have the potential to produce 1.5” total in 45-60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	Current TO 1159 PM	Current TO 1130 PM
Jefferson County	1	Current TO 1159 PM	Current TO 1130 PM
Broomfield County	1	Current TO 1159 PM	Current TO 1130 PM
Douglas County	1	Current TO 1159 PM	Current TO 1130 PM
Adams County	1	Current TO 1159 PM	Current TO 1130 PM
Denver County	1	Current TO 1159 PM	Current TO 1130 PM
DIA	1	Current TO 1159 PM	Current TO 1130 PM
Arapahoe County	1	Current TO 1159 PM	Current TO 1130 PM
the City of Aurora	1	Current TO 1159 PM	Current TO 1130 PM
Arvada	1	Current TO 1159 PM	Current TO 1130 PM
Wheat Ridge	1	Current TO 1159 PM	Current TO 1130 PM
Lakewood	1	Current TO 1159 PM	Current TO 1130 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Arapahoe	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Boulder	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Broomfield	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Denver	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Douglas	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Jefferson	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Douglas	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED
Jefferson	Current TO 1159 PM THU	Trace (95%) to 0.25" (50%) to 0.75" (20%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.