Flash Flood Prediction Program

-	Message 1's have been issued for the entire District and will be valid from 1:00-8:00pm. Thunderstorms that develop today will be fast moving, but contain the risk of brief heavy rainfall that may lead to excessive runoff.
-	Very fast storm motions from S to N at 30-40mph will limit point rainfall amounts from a single storm. However, a surface wind convergence line currently located over central Douglas County extending E/NE could allow storms to anchor briefly or move more slowly. Training of multiple thunderstorm cells over a single location may also result in an extended period of heavy rainfall.
-	Thunderstorms that develop today will not only have the potential for heavy rainfall and may tend to become severe in nature with gusty winds in excess of 60mph, large hail of 1" or more in diameter and possibly a very isolated tornado. Best chances for strong/severe storms will be between 1:30-7:00pm.

STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers and thunderstorms will have the potential to produce 0.1-0.3" in 10-30 minutes. Strong thunderstorms will have the potential to produce 0.3-0.7" in 10-30 minutes.

WORST CASE SCENARIO: An anchored strong thunderstorm or training of thunderstorm cells may result in up to 1.5" of rain in 45-60 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	100 PM TO 800 PM	200 PM TO 700 PM
Jefferson County	1	100 PM TO 800 PM	200 PM TO 700 PM
Broomfield County	1	100 PM TO 800 PM	200 PM TO 700 PM
Douglas County	1	100 PM TO 800 PM	130 PM TO 700 PM
Adams County	1	100 PM TO 800 PM	200 PM TO 700 PM
Denver County	1	100 PM TO 800 PM	200 PM TO 700 PM
DIA	1	100 PM TO 800 PM	200 PM TO 700 PM
Arapahoe County	1	100 PM TO 800 PM	130 PM TO 700 PM
the City of Aurora	1	100 PM TO 800 PM	200 PM TO 700 PM
Arvada	1	100 PM TO 800 PM	200 PM TO 700 PM
Wheat Ridge	1	100 PM TO 800 PM	200 PM TO 700 PM
Lakewood	1	100 PM TO 800 PM	200 PM TO 700 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	100 PM TO 800 PM	0.1" (90%) to 0.3" (60%) to 0.7" (30%)	ISSUED
Arapahoe	100 PM TO 800 PM	0.1" (95%) to 0.3" (75%) to 0.7" (35%)	ISSUED
Boulder	100 PM TO 800 PM	0.1" (90%) to 0.3" (60%) to 0.7" (30%)	ISSUED
Broomfield	100 PM TO 800 PM	0.1" (90%) to 0.3" (60%) to 0.7" (30%)	ISSUED
Denver	100 PM TO 800 PM	0.1" (90%) to 0.3" (60%) to 0.7" (30%)	ISSUED
Douglas	100 PM TO 800 PM	0.1" (95%) to 0.3" (75%) to 0.7" (35%)	ISSUED
Jefferson	100 PM TO 800 PM	0.1" (90%) to 0.3" (60%) to 0.7" (30%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 800 PM SAT	0.1" (95%) to 0.3" (60%) to 0.7" (30%)	ISSUED
Douglas	Current TO 800 PM SAT	0.1" (95%) to 0.3" (75%) to 0.7" (35%)	ISSUED
Jefferson	Current TO 800 PM SAT	0.1" (95%) to 0.3" (60%) to 0.7" (30%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.