Flash Flood Prediction Program

Message 1’s have been issued for the entire District effective until 9:00pm this evening.

A round of storms have moved into the District bringing isolated moderate to heavy rainfall with 0.20”-0.25” in 5-10min out of some cells. These storms will continue to impact the District over the next few hours, with a few lingering showers possible through midnight.

Storms will generally move from west to east between 10-20mph, however, gust front have caused a few storms to become stationary, and these storms will provide the largest threat for moderate to brief heavy rainfall. Storms may also contain gusty winds and frequent cloud-to-ground lightning. The largest threat will be a quick 0.50” in 10-30 minutes rather than any long lasting rain.

Storms should weaken in intensity behind this first round with off and on showers possible until midnight. Overnight will be partly cloudy with low temperatures dropping into the low 60s on the plains with mid to upper 50s along the foothills.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers/thunderstorms today will produce a trace to 0.30" total in 10-30
minutes. Moderate to strong thunderstorms will produce up to 0.30-0.60” in 10-30 minutes.

WORST CASE SCENARIO: Stationary thunderstorms, or training of thunderstorm cells have the
potential to produce up to 1.20” total in 30-60 minutes.

County	Message	Valid Times	Prime Time
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
Lakewood	1	Current TO 900 PM	Current TO 830 PM
Arvada	1	Current TO 900 PM	Current TO 830 PM
Wheat Ridge	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 1159 PM SAT	Trace (80%) to 0.25" (60%) to 0.5" (40%)	ISSUED
Arapahoe	Current TO 1159 PM SAT	Trace (80%) to 0.25" (60%) to 0.5" (40%)	ISSUED
Boulder	Current TO 1159 PM SAT	Trace (80%) to 0.25" (40%) to 0.5" (20%)	ISSUED
Broomfield	Current TO 1159 PM SAT	Trace (80%) to 0.25" (40%) to 0.5" (20%)	ISSUED
Denver	Current TO 1159 PM SAT	Trace (80%) to 0.25" (60%) to 0.5" (40%)	ISSUED
Douglas	Current TO 1159 PM SAT	Trace (80%) to 0.25" (40%) to 0.5" (20%)	ISSUED
Jefferson	Current TO 1159 PM SAT	Trace (80%) to 0.25" (40%) to 0.5" (20%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 1159 PM SAT	Trace (80%) to 0.25" (40%) to 0.5" (20%)	ISSUED
Douglas	Current TO 1159 PM SAT	Trace (80%) to 0.25" (40%) to 0.5" (20%)	ISSUED
Jefferson	Current TO 1159 PM SAT	Trace (80%) to 0.25" (40%) to 0.5" (20%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.