Time: 854 AM Fri June 9, 2023 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- A DECREASE IN THUNDERSTORM ACTIVITY IS EXPECTED TODAY A decrease in thunderstorm activity is expected today but there will still be a modest chance for isolated to widely scattered afternoon and evening showers/thunderstorms. Temperatures will warm into the lower 80’s for many locations over the plains which is near normal for the date with 70’s in the Front Range foothills. Normal high for Denver today is 81 degrees. Thunderstorms will develop over the foothills between noon and 2pm. Upper level steering winds from SW to NE will push storms onto the plains by 2-3pm. A round or two of showers and thunderstorms are expected through the afternoon and early evening with conditions drying out after sunset. Typical storms today will be light to brief moderate rainfall producers with a slight chance for a stronger thunderstorm that would have the potential for brief heavy rainfall. The threat for heavy rainfall is lower than previous days as surface moisture has decreased with dew points expected to drop into the lower 40’s. Dry conditions are expected for the later evening and overnight period. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2” of rain. Moderate to strong thunderstorms will produce rainfall rates of 0.2-0.5” in 10-30 minutes. WORST CASE SCENARIO: Dew points remain higher than anticipated with strong thunderstorms capable of producing rainfall rates of 0.3-0.8” in 10-30 minutes with up to 1.2” possible in 45-60 minutes. A LOOK AHEAD: A cold front will move through on Saturday and increase moisture once again with scattered afternoon showers and thunderstorms. Strong thunderstorms will be capable of producing heavy rainfall. Cooler Sunday with afternoon high temperatures likely remaining in the 60’s over the plains. Scattered to numerous rain showers are expected with embedded thunderstorms likely. Thunderstorms will contain heavy rainfall. Continued cool on Monday with more showers and thunderstorms. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM Trace (70%) to 0.2" (40%) to 0.5" (20%) LOW Arapahoe 200 PM TO 800 PM Trace (70%) to 0.2" (40%) to 0.5" (20%) LOW Boulder 200 PM TO 800 PM Trace (70%) to 0.2" (40%) to 0.5" (20%) LOW Broomfield 200 PM TO 800 PM Trace (70%) to 0.2" (40%) to 0.5" (20%) LOW Denver 200 PM TO 800 PM Trace (70%) to 0.2" (40%) to 0.5" (20%) LOW Douglas 200 PM TO 800 PM Trace (70%) to 0.2" (40%) to 0.5" (20%) LOW Jefferson 200 PM TO 800 PM Trace (70%) to 0.2" (40%) to 0.5" (20%) LOW Foothills above 6500ft       Boulder 100 PM TO 800 PM Trace (80%) to 0.2" (50%) to 0.5" (25%) LOW Douglas 100 PM TO 800 PM Trace (80%) to 0.2" (50%) to 0.5" (25%) LOW Jefferson 100 PM TO 800 PM Trace (80%) to 0.2" (50%) to 0.5" (25%) 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]