Flash Flood Prediction Program

Time: 342 PM Fri August 19, 2022 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR THE ENTIRE DISTRICT - Message 1's have been issued for the entire District and will be valid until 10:00 PM. - A few storms have initiated along the higher terrain towards the west and south along the Palmer Divide. A boundary has set up from north to south from Brighton through Parker and is currently the focus point for stronger storm development this afternoon. Storm motions are generally expected from NW to SE between 5-10mph, however some storm motions today have been erratic as storms pulse up quickly, with additional storms developing off outflow boundaries which has increased the chance for brief heavy rainfall this afternoon and evening. - The best chance for storms will be from now through 10pm this evening with stronger storms capable of producing heavy rainfall that may lead to excessive runoff. The largest threat today will be a quick 0.5" in 10-15 minutes. The stronger storms will likely be isolated with best chances along and E of I-25 at this time. Storm chances taper off after 10pm as the overnight dries out with mild conditions expected into daybreak Saturday. STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.4-0.9" in 10-30 minutes. WORST CASE SCENARIO: A slower moving or briefly anchored strong thunderstorm may produce rainfall amounts of up to 1.8" in 45-75 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 1000 PM Current TO 900 PM Jefferson County 1 Current TO 1000 PM Current TO 900 PM Broomfield County 1 Current TO 1000 PM Current TO 900 PM Douglas County 1 Current TO 1000 PM Current TO 900 PM Adams County 1 Current TO 1000 PM Current TO 900 PM Denver County 1 Current TO 1000 PM Current TO 900 PM DIA 1 Current TO 1000 PM Current TO 900 PM Arapahoe County 1 Current TO 1000 PM Current TO 900 PM the City of Aurora 1 Current TO 1000 PM Current TO 900 PM Arvada 1 Current TO 1000 PM Current TO 900 PM Wheat Ridge 1 Current TO 1000 PM Current TO 900 PM Lakewood 1 Current TO 1000 PM Current TO 900 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1000 PM FRI 0.1" (50%) to 0.4" (25%) to 0.9" (15%) ISSUED Arapahoe Current TO 1000 PM FRI 0.1" (50%) to 0.4" (25%) to 0.9" (15%) ISSUED Boulder Current TO 1000 PM FRI 0.1" (40%) to 0.4" (20%) to 0.9" (10%) ISSUED Broomfield Current TO 1000 PM FRI 0.1" (40%) to 0.4" (20%) to 0.9" (10%) ISSUED Denver Current TO 1000 PM FRI 0.1" (50%) to 0.4" (25%) to 0.9" (15%) ISSUED Douglas Current TO 1000 PM FRI 0.1" (50%) to 0.4" (25%) to 0.9" (15%) ISSUED Jefferson Current TO 1000 PM FRI 0.1" (40%) to 0.4" (20%) to 0.9" (10%) ISSUED Foothills above 6500ft       Boulder Current TO 1000 PM FRI 0.1" (50%) to 0.4" (25%) to 0.9" (15%) ISSUED Douglas Current TO 1000 PM FRI 0.1" (50%) to 0.4" (25%) to 0.9" (15%) ISSUED Jefferson Current TO 1000 PM FRI 0.1" (50%) to 0.4" (25%) to 0.9" (15%) ISSUED MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]