Flash Flood Prediction Program

Message 1’s have been issued for the entire District and will be valid until 9:00pm this evening. The clouds have decreased this morning and temperatures are already reaching the low to mid 60’s and will likely warm a bit more before cloud cover increases again and storms begin to develop. Daytime heating in tandem with abundant surface moisture with dew points in the lower 50’s will result in thunderstorms developing over the next few hours and remaining possible into the evening. Best chances for thunderstorm activity through the afternoon and early evening between noon and 8pm. With all of the rain recently the ground is near saturation for many areas and thunderstorms today will have the potential to produce heavy rainfall which may result in excessive runoff and possibly flash flooding.

Typical showers and thunderstorms will move from W to E at 15-20mph but stronger storms may move more slowly or become right movers and track more from the NW to SE. After 8 or 9pm the chances for thunderstorms will diminish with cooling temperatures and light rain showers are expected to continue periodically overnight into early Friday morning.

STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.5” of rain. Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.5-1.5” in 10-30 minutes.

WORST CASE SCENARIO: A slower moving strong thunderstorm or a large thunderstorm complex may result in up to 2.0” of rain in 45-60 minutes.

County	Message	Valid Times	Prime Time
Lakewood	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Arvada	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Wheat Ridge	1	1130 AM TO 900 PM	1230 PM TO 800 PM
the City of Aurora	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Denver County	1	1130 AM TO 900 PM	1230 PM TO 800 PM
DIA	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Arapahoe County	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Adams County	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Boulder County	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Jefferson County	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Broomfield County	1	1130 AM TO 900 PM	1230 PM TO 800 PM
Douglas County	1	1130 AM TO 900 PM	1230 PM TO 800 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	1200 PM TO 900 PM	0.1" (80%) to 0.5" (50%) to 1.5" (20%)	ISSUED
Arapahoe	1200 PM TO 900 PM	0.1" (85%) to 0.5" (55%) to 1.5" (25%)	ISSUED
Boulder	1200 PM TO 900 PM	0.1" (85%) to 0.5" (55%) to 1.5" (25%)	ISSUED
Broomfield	1200 PM TO 900 PM	0.1" (80%) to 0.5" (50%) to 1.5" (20%)	ISSUED
Denver	1200 PM TO 900 PM	0.1" (80%) to 0.5" (50%) to 1.5" (20%)	ISSUED
Douglas	1200 PM TO 900 PM	0.1" (90%) to 0.5" (60%) to 1.5" (30%)	ISSUED
Jefferson	1200 PM TO 900 PM	0.1" (85%) to 0.5" (55%) to 1.5" (25%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM THU	0.1" (90%) to 0.5" (60%) to 1.5" (30%)	ISSUED
Douglas	Current TO 900 PM THU	0.1" (90%) to 0.5" (60%) to 1.5" (30%)	ISSUED
Jefferson	Current TO 900 PM THU	0.1" (90%) to 0.5" (60%) to 1.5" (30%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.