Time: 852 AM Sat June 26, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- ANOTHER COOL DAY WITH A GOOD CHANCE FOR AFTERNOON & EVENING THUNDERSTORMS - Another unseasonably cool day with high temperatures 10-15 degrees cooler than normal in the upper 60's to low 70's this afternoon. Low to mid 50's dew points currently will remain in place throughout the day along with good mid to upper-level moisture will result in another chance for heavy rainfall. The severity of storms will be dependent on whether or not we have enough daytime heating before the cold front to break the cap today, however even weak rain showers will be very efficient rain producers resulting in a good chance for moderate to brief heavy rain. - As the cold front passes through the region early this afternoon it will bring a good chance for rain showers/isolated thunderstorms for the District. Storm motions have shifted today from NW to SE around 5-15mph, although outflow boundaries could produce some erratic, slower moving storms, especially along the foothills where storms have the best chance to anchor today, resulting in longer duration rainfall with an increased chance for minor flooding. Best chance for storms will be from 12-8pm with a few lingering rain showers possible after 8pm. - If there is enough daytime heating today and temperatures are able to increase into the mid to upper 70's, there will be a better chance for severe weather for the District including strong winds and hail 1" in diameter or greater, although the threat for this is unlikely at this time. Overnight skies will gradually clear with lows dropping into the upper 50's to low 60's across the plains. with low to mid 50's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers/isolated thunderstorms will produce 0.1-0.3" in 10-30 minutes. a moderate to strong thunderstorm will produce 0.3-0.9" in 10-30 minutes. WORST CASE SCENARIO: An anchored strong thunderstorm or training of strong thunderstorms will have the potential to produce 1.8" in 60-90 minutes. A LOOK AHEAD: A lull in rain shower activity in Sunday morning with mostly sunny skies early before another disturbance moves into the region once again Sunday afternoon bringing a chance for afternoon/evening rain/isolated thunderstorms. This disturbance will linger a bit longer over the region resulting in a chance for overnight rain showers into early Monday morning. Increased moisture remains in place, therefore the threat for heavy rain will continue Sunday afternoon and evening. Monday will stay cooler with a slight chance for afternoon rain/isolated thunderstorms with the threat for heavy rain dropping significantly. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1200 PM TO 800 PM 0.1" (80%) to 0.3" (50%) to 0.9" (25%) MOD Arapahoe 1200 PM TO 800 PM 0.1" (80%) to 0.3" (50%) to 0.9" (25%) MOD Boulder 1200 PM TO 800 PM 0.1" (80%) to 0.3" (60%) to 0.9" (30%) MOD Broomfield 1200 PM TO 800 PM 0.1" (80%) to 0.3" (50%) to 0.9" (25%) MOD Denver 1200 PM TO 800 PM 0.1" (80%) to 0.3" (50%) to 0.9" (25%) MOD Douglas 1200 PM TO 800 PM 0.1" (80%) to 0.3" (60%) to 0.9" (30%) MOD Jefferson 1200 PM TO 800 PM 0.1" (80%) to 0.3" (60%) to 0.9" (30%) MOD Foothills above 6500ft       Boulder 1200 PM TO 800 PM 0.1" (80%) to 0.3" (60%) to 0.9" (40%) MOD Douglas 1200 PM TO 800 PM 0.1" (80%) to 0.3" (60%) to 0.9" (40%) MOD Jefferson 1200 PM TO 800 PM 0.1" (80%) to 0.3" (60%) to 0.9" (40%) MOD MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]