Time: 902 AM Fri August 11, 2023 Forecaster: Laura Smith ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARM AND SUNNY WITH LATE AFTERNOON TO EARLY EVENING ISOLATED SHOWERS West-northwesterly flow aloft has developed broadly across Colorado as an upper-level disturbance traverses the Northern Plains. As a result, down sloping winds will help to suppress thunderstorm activity today on the Plains. This morning will be sunny followed by high temperatures in the upper 80s to low 90s and dew points in the low 40s. Scattered showers and thunderstorms will develop over the mountains this afternoon. A few storms will move east of the mountains in the late afternoon and evening. Lightning activity will be limited, but weak showers may produce localized gusty winds with little rain. STORM RAINFALL POTENTIAL AND DURATION: Typical showers will be weak, producing rainfall of TR-0.20” total in 10-30 minutes. Stronger storms have the potential to produce heavy rainfall of 0.20” to 0.40” total in 10-30 minutes. WORST CASE SCENARIO: Training thunderstorms have the potential to produce 0.40” to 0.80” in 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 400 PM TO 1000 PM Trace (30%) to 0.2" (20%) to 0.4" (10%) NONE Arapahoe 400 PM TO 1000 PM Trace (30%) to 0.2" (20%) to 0.4" (10%) NONE Boulder 400 PM TO 1000 PM Trace (30%) to 0.2" (20%) to 0.4" (10%) NONE Broomfield 400 PM TO 1000 PM Trace (30%) to 0.2" (20%) to 0.4" (10%) NONE Denver 400 PM TO 1000 PM Trace (30%) to 0.2" (20%) to 0.4" (10%) NONE Douglas 400 PM TO 1000 PM Trace (30%) to 0.2" (20%) to 0.4" (10%) NONE Jefferson 400 PM TO 1000 PM Trace (30%) to 0.2" (20%) to 0.4" (10%) NONE Foothills above 6500ft       Boulder 200 PM TO 1000 PM Trace (35%) to 0.2" (25%) to 0.4" (15%) NONE Douglas 200 PM TO 1000 PM Trace (35%) to 0.2" (25%) to 0.4" (15%) NONE Jefferson 200 PM TO 1000 PM Trace (35%) to 0.2" (25%) to 0.4" (15%) 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]