Time: 447 PM Fri August 11, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- STRONGER STORMS MOVING OVER THE FOOTHILLS CURRENTLY WITH POCKETS OF HEAVY RAINFALL An isolated stronger thunderstorm is currently moving over the foothills and should enter the District over the next hour or so. This cell isn’t particularly strong; however, this storm did trigger 0.20" in 5-10 minutes, resulting in an upgrade to a LOW Message potential heading into this evening. Storms have mostly mixed out this afternoon and will likely continue to do so. Although a gust front could produce a stronger storm development withing the District with the potential for some brief isolated heavy rainfall into this evening. Storm chances should taper off by sunset with a few lingering off and on showers possible through 10pm. STORM RAINFALL POTENTIAL AND DURATION: Typical showers/weak thunderstorms will produce a trace to 0.25” in 10 to 30 minutes. A weak to moderate thunderstorm will produce 0.25 to 0.50” in 10 to 30 minutes. WORST CASE SCENARIO: A strong thunderstorm has the potential to produce up to 1.00” in under 60 minutes. A LOOK AHEAD: Conditions will be similar this weekend, with highs in the upper 80s to low 90s and a slight chance for isolated showers and thunderstorms. On Sunday evening, an upper-level disturbance and its associated cold front will bring a chance for scattered showers and storms across the Front Range Urban Corridor. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Arapahoe Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Boulder Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Broomfield Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Denver Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Douglas Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Jefferson Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Douglas Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Jefferson Current TO 1000 PM FRI Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]