Flash Flood Prediction Program

Messages have been extended until 10pm as the threat of heavy rain persists.

A gust front from the northeast is approaching the District at this time. This gust has stirred up storms around Greeley and could also initiate storms in the District over the next couple of hours.

Storms have not been that strong behind the gust front. However, a pulse up thunderstorm with mid to upper level 50’s dew points could result in a storm with quick 0.5” in 10-20 minutes. Typical storm motions will be from west to east between 10-20mph, although, storms could anchor in place behind this gust front.

There is a chance storms do not initiate behind this gust front within the District, and IMS to end Messages earlier than 10pm may be possible this evening.

STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers/weak thunderstorms produce 0.20-0.40” total, 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: A large thunderstorm or briefly anchored strong thunderstorm may result in up to 2.0" of rain in 45-60 minutes.

County	Message	Valid Times	Prime Time
Adams County	1	Current TO 1000 PM	Current TO 930 PM
Douglas County	1	Current TO 1000 PM	Current TO 930 PM
Broomfield County	1	Current TO 1000 PM	Current TO 930 PM
Jefferson County	1	Current TO 1000 PM	Current TO 930 PM
Boulder County	1	Current TO 1000 PM	Current TO 930 PM
Denver County	1	Current TO 1000 PM	Current TO 930 PM
DIA	1	Current TO 1000 PM	Current TO 930 PM
Arapahoe County	1	Current TO 1000 PM	Current TO 930 PM
the City of Aurora	1	Current TO 1000 PM	Current TO 930 PM
Arvada	1	Current TO 1000 PM	Current TO 930 PM
Wheat Ridge	1	Current TO 1000 PM	Current TO 930 PM
Lakewood	1	Current TO 1000 PM	Current TO 930 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Arapahoe	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Boulder	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Broomfield	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Denver	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Douglas	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Jefferson	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Douglas	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED
Jefferson	Current TO 1000 PM SAT	0.2" (50%) to 0.4" (25%) to 1.2" (10%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.