Flash Flood Prediction Program

Time: 816 AM Mon June 7, 2021 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- UNSEASONABLY WARM WITH ISOLATED AFTERNOON THUNDERSTORMS - Unseasonably warm temperatures will continue over the District today with readings in the upper 80's to lower 90's over the plains. Somewhat drier air will move overhead and reduce the thunderstorm coverage today. There will still be isolated afternoon thunderstorms but the heavier rain threat pushes eastward with storms that develop today generally producing light rain and gusty winds. - By early afternoon thunderstorm activity will initiate over the higher terrain to the west. Upper level steering winds will push the storms eastward onto the I-25 corridor by 2 or 3pm. Isolated storm coverage is then expected until around sunset. Most storms will trend on the weaker side but a stronger thunderstorm will be capable of producing brief moderate to possibly heavy rain. - After sunset as daytime heating is lost any shower or thunderstorm activity will diminish with dry conditions for the overnight period. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.10" of rain. Moderate thunderstorms will have the potential to produce 0.1-0.3" in 10-30 minutes. WORST CASE SCENARIO: Surface moisture remains higher than anticipated resulting in a strong thunderstorm with the potential for heavy rainfall of 0.3-0.8" in 10-30 minutes. A LOOK AHEAD: Temperatures on Tuesday will warm well into the 90's over the plains with 80's in the Front Range foothills. Thunderstorm activity lifts northward with dry conditions expected south of the CO/WY border over the plains with possibly a higher elevation afternoon thunderstorm. Hot and dry weather then looks to continue through the rest of the work week with a chance for thunderstorms returning over weekend. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM Trace (65%) to 0.1" (30%) to 0.3" (15%) NONE Arapahoe 200 PM TO 800 PM Trace (65%) to 0.1" (30%) to 0.3" (15%) NONE Boulder 200 PM TO 800 PM Trace (65%) to 0.1" (30%) to 0.3" (15%) NONE Broomfield 200 PM TO 800 PM Trace (65%) to 0.1" (30%) to 0.3" (15%) NONE Denver 200 PM TO 800 PM Trace (65%) to 0.1" (30%) to 0.3" (15%) NONE Douglas 200 PM TO 800 PM Trace (65%) to 0.1" (30%) to 0.3" (15%) NONE Jefferson 200 PM TO 800 PM Trace (65%) to 0.1" (30%) to 0.3" (15%) NONE Foothills above 6500ft       Boulder 100 PM TO 800 PM Trace (80%) to 0.1" (40%) to 0.3" (20%) NONE Douglas 100 PM TO 800 PM Trace (80%) to 0.1" (40%) to 0.3" (20%) NONE Jefferson 100 PM TO 800 PM Trace (80%) to 0.1" (40%) to 0.3" (20%) 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]