Flash Flood Prediction Program

Time: 918 AM Mon September 18, 2023 Forecaster: Laura Smith ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- SLIGHT CHANGE FOR ISOLATED LATE AFTERNOON TO EVENING SHOWERS AND THUNDERSTORMS A layer of high clouds has developed across the Front Range Urban Corridor this morning as light westerly flow aloft remains in place. Afternoon temperatures are expected to reach the low to mid 80s, with dew points in the 30s and PWAT values around 0.50”. These conditions support a chance for isolated showers and thunderstorms late this afternoon to evening. Storms are expected to dissipate by the evening hours, with skies gradually clearing overnight. STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce light rainfall of up to 0.25” total in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm has the potential to produce up to 0.50” total rainfall 10-30 minutes. A LOOK AHEAD: Tomorrow will be more active as a short wave traverses the state. Afternoon temperatures will be in the upper 70s to low 80s with isolated storms. Wednesday will be similar with high temperatures in the upper 70s to low 80s and isolated showers and thunderstorms. This pattern will remain in place through the remainder of the week with afternoon temperatures in the upper 70s to low 80s and a chance for isolated storms. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Arapahoe 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Boulder 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Broomfield 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Denver 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Douglas 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Jefferson 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Foothills above 6500ft       Boulder 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Douglas 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE Jefferson 400 PM TO 900 PM 0.05" (75%) to 0.15" (50%) to 0.25" (25%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]