Time: 910 AM Wed June 29, 2022 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- TEMPERATURES REACH THEIR PEAK WITH ISOLATED AFTERNOON AND EVENING THUNDERSTORMS POSSIBLE - Temperatures will reach their peak today, topping out in the 90's over the plains with 80's in the Front Range foothills. Upper level flow will become more westerly today and with just enough moisture to work with isolated afternoon thunderstorms are expected, more numerous over the foothills. A cold front will then move through this evening keeping the chances for showers and possibly a thunderstorm into the late evening hours. - Between noon-2pm the initial storms will develop over the foothills and then move eastward onto the plains, likely weakening as they do so as surface moisture is lacking with dew points in the 30's. Most storms today will produce gusty winds in excess of 30-40mph and light rainfall/sprinkles through the evening. Steering winds aloft will generally be from W to E at 15-20mph. - Later this evening, sometime between 8pm and midnight a cold front will move through and will likely produce the best chances for precipitation today as a few showers and possibly a weak thunderstorm may develop as the front moves through. After midnight conditions expected to dry out for the remainder of the overnight period. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.1" of rain. A moderate thunderstorm will have the potential to produce 0.1-0.3" of rain in 10-30 minutes. WORST CASE SCENARIO: A stronger thunderstorm is able to develop this evening along a cold front resulting in rainfall rates of 0.2-0.6" in 10-30 minutes. A LOOK AHEAD: Temperatures will be about 10 degrees cooler on Thursday and with more moisture to work with there will be a significant increase in thunderstorms. Scattered thunderstorm activity is expected to develop shortly after noon over the foothills then spread out onto the plains by early afternoon. Multiple rounds of showers and thunderstorms will then be likely into the evening with additional rain showers possible overnight. Some storms Thursday may become strong to severe with moderate to heavy rainfall and possibly hail. A high risk for thunderstorms will the potential to produce heavy rainfall will continue Friday, Saturday and Sunday. The first Message day of the season is expected over the coming days. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 1159 PM Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE Arapahoe 200 PM TO 1159 PM Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE Broomfield 200 PM TO 1159 PM Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE Denver 200 PM TO 1159 PM Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE Boulder 100 PM TO 1159 PM Trace (70%) to 0.1" (30%) to 0.3" (15%) NONE Douglas 100 PM TO 1159 PM Trace (70%) to 0.1" (30%) to 0.3" (15%) NONE Jefferson 100 PM TO 1159 PM Trace (70%) to 0.1" (30%) to 0.3" (15%) NONE Foothills above 6500ft       Boulder 1200 PM TO 1159 PM Trace (80%) to 0.1" (40%) to 0.3" (20%) NONE Douglas 1200 PM TO 1159 PM Trace (80%) to 0.1" (40%) to 0.3" (20%) NONE Jefferson 1200 PM TO 1159 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]