Time: 903 AM Fri May 28, 2021 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARMER WITH ISOLATED HIGH-BASED AFTERNOON/EVENING THUNDERSTORMS - Temperatures will warm to slightly above normal today over the District with just enough moisture to produce a few isolated high-based showers and weak thunderstorms this afternoon. Highs will reach the upper 70's to lower 80's over the plains under sunny skies this morning. Normal high for Denver today is 77 degrees. - Cloud cover will increase by early afternoon as high based showers and weak thunderstorms begin to develop over the mountains and foothills. Westerly flow aloft will push storms over the plains into the afternoon with best chances between 2-8pm. With minimal moisture to work with the majority of storms that develop today will produce light rainfall/sprinkles and gusty winds. Many areas will likely remain on the drier side today outside the foothills. - By sunset any shower or thunderstorm activity will diminish. A cold front will move through early Saturday morning and may result in low clouds and possibly some areas of fog/mist over the plains into daybreak. STORM RAINFALL POTENTIAL AND DURATION: Typical high based rain showers and weak thunderstorms will produce a trace to 0.1" of rain. A moderate thunderstorm over the higher terrain may result in 0.1-0.3" in 10-30 minutes. A LOOK AHEAD: Shower and thunderstorm chances increase significantly over the weekend as a trough of low pressure moves through... Cooler Saturday in the 60's to around 70 with increased surface moisture behind a cold front. A round or two of thunderstorms is expected through the afternoon with some storms potentially producing moderate to heavy rainfall that may lead to excessive runoff. Stronger storms may also become severe with damaging winds and large hail being the primary threats. On Sunday temperatures may struggle to reach the 60s over the plains with rain showers possible throughout the day and if there is enough warming there will be a threat for afternoon thunderstorms with heavy rainfall. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Arapahoe 200 PM TO 800 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Broomfield 200 PM TO 800 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Denver 200 PM TO 800 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Boulder 130 PM TO 800 PM Trace (50%) to 0.1" (20%) to 0.3" (5%) NONE Douglas 130 PM TO 800 PM Trace (60%) to 0.1" (20%) to 0.3" (5%) NONE Jefferson 130 PM TO 800 PM Trace (50%) to 0.1" (20%) to 0.3" (5%) NONE Foothills above 6500ft       Boulder 100 PM TO 800 PM Trace (75%) to 0.1" (50%) to 0.3" (10%) NONE Douglas 100 PM TO 800 PM Trace (80%) to 0.1" (60%) to 0.3" (20%) NONE Jefferson 100 PM TO 800 PM Trace (75%) to 0.1" (50%) to 0.3" (10%) 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]