Flash Flood Prediction Program

Time: 837 AM Sat July 24, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- COOL TODAY WITH A SLIGHT CHANCE FOR RAIN SHOWERS/ISOLATED THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING - A cold front will result in cooler high temperatures today with upper 70's to low 80's across the plains with low to mid 70's along the foothills. Currently a few scattered weak to moderate showers along the Palmer Divide and into southern portions of the District. These showers will remain in place through most of the morning and into the afternoon which should also help limit temperatures with increased cloud cover throughout the day. - However, with adequate surface moisture and possibly a few breaks in the clouds, could raise temperatures enough to get a stronger storm to develop along the Palmer Divide which in turn could produce a gust front which would have the potential to trigger storms northward and into the District. The best chance for storms to develop today will be between noon and 6pm with a few scattered rain showers possible through sunset and into the early evening before skies gradually clear out after midnight. - Overnight will be mild with lows dropping into the mid to upper 60's for the plains with upper 50's to low 60's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce TR-0.2" in 10-30 minutes. Strong thunderstorms have the potential to produce 0.2-0.8" of heavy rain in 10-30 minutes. WORST CASE SCENARIO: A nearly stationary strong thunderstorm may result in up to 1.6" in 60 minutes or less. A LOOK AHEAD: Sunday will already begin a decent warm up as high temperatures jump back into the 90's resulting in a slightly better chance for afternoon rain showers/isolated thunderstorms. With excess moisture in place at the surface and in the mid to upper-level another low chance for heavy rain will persist into Sunday. Heat and high-pressure returns Monday and through the rest of next week keeping high temperatures in the 90's with only a slight chance for afternoon/evening rain showers/isolated thunderstorms. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1200 PM TO 900 PM Trace (40%) to 0.2" (20%) to 0.8" (5%) LOW Arapahoe 1200 PM TO 900 PM Trace (40%) to 0.2" (20%) to 0.8" (5%) LOW Boulder 1200 PM TO 900 PM Trace (40%) to 0.2" (20%) to 0.8" (5%) LOW Broomfield 1200 PM TO 900 PM Trace (40%) to 0.2" (20%) to 0.8" (5%) LOW Denver 1200 PM TO 900 PM Trace (40%) to 0.2" (20%) to 0.8" (5%) LOW Douglas 1200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.8" (15%) MOD Jefferson 1200 PM TO 900 PM Trace (50%) to 0.2" (25%) to 0.8" (10%) LOW Foothills above 6500ft       Boulder 1200 PM TO 900 PM Trace (40%) to 0.2" (20%) to 0.8" (5%) LOW Douglas 1200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.8" (15%) MOD Jefferson 1200 PM TO 900 PM Trace (50%) to 0.2" (25%) to 0.8" (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]