Time: 930 AM Mon June 6, 2022 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WETTING RAINFALL FROM THUNDERSTORMS TODAY - An upper level disturbance and weak cool front is expected to increase thunderstorm activity today over the District. The front will have minimal impact on temperatures as they will be near normal for this time of year in the lower 80's for highs over the plains with 70's in the Front Range foothills. More importantly, surface moisture has increased allowing storms that develop today to produce wetting rainfall with minor runoff possible. - Heavy rainfall is not expected as most storms will produce light to moderate rainfall with strong storms potentially producing brief heavy rain as well as gusty winds and possibly hail. Best chances for stronger storms today will be E of the District where moisture is deeper, but a very isolated strong storm cannot be ruled out. 1-3 rounds of showers and thunderstorms is expected to move through during the afternoon with isolated light rain showers continuing possible into the early overnight period. - Thunderstorms will first develop over the higher terrain to the W between 11am and 1pm. Upper level steering winds will then push the storm activity onto the plains by 1-2pm. Prime time for thunderstorm activity will be between 2-10pm. Storm motions from W/WNW to E/ESE at 15-25mph will keep storms moving along and rainfall brief from a single storm. Training of thunderstorm cells may result in longer periods of rainfall. After 10pm thunderstorm activity is expected to have diminished with a few light rain showers possible through midnight. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" in 10-30 minutes. Moderate to briefly strong thunderstorms will have the potential to produce 0.2-0.5" in 10-30 minutes. WORST CASE SCENARIO: Training of moderate to strong thunderstorm cells may produce rainfall amounts of up to 1.0" in 45-60 minutes. A LOOK AHEAD: We will tack on a few degrees to high temperatures on Tuesday with readings in the low to mid 80's over the plains. Thunderstorm coverage will decrease but surface moisture will remain resulting in the storms that do develop potentially becoming moderate to strong. Best chances however, will be to the S and E of the District. A little cooler Wednesday with isolated to widely scattered thunderstorms expected. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW Arapahoe 200 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW Broomfield 200 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW Denver 200 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW Boulder 100 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW Douglas 100 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW Jefferson 100 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW Foothills above 6500ft       Boulder 1200 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (20%) LOW Douglas 1200 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (20%) LOW Jefferson 1200 PM TO 1000 PM Trace (95%) to 0.2" (60%) to 0.5" (20%) 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]