Flash Flood Prediction Program

Time: 806 PM Thu August 19, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- A CHANCE FOR OVERNIGHT RAIN SHOWERS AND POSSIBLY A FEW ISOLATED THUNDERSTORMS - As the disturbance continues to move through Colorado there will be a chance through the overnight for an additional round of rain showers/isolated thunderstorms. - At this time, the best chance for an additional round of rain showers/isolated thunderstorms will be between 2-6am Friday. Due to the timing, the most likely outcome will be rain showers with typically a trace to 0.2" of rainfall in 10-30 minutes. However, an isolated thunderstorm cannot be completely ruled out which could produce 0.2-0.5" in 10-30 minutes. Storms will be moving from west to east fairly quickly between 10-20mph which will help limit point rainfall amounts, however a slower moving storm, or possible training of rain showers/thunderstorms has the potential to produce moderate to brief heavy rainfall. - By daybreak, chances will subside for any additional rain showers throughout the rest of the day with dry conditions likely into Saturday. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce a trace to 0.2" of rain. Weak to moderate thunderstorms will have the potential to produce 0.2-0.5" in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm is able to develop with the potential to produce heavy rainfall of 1.0" in 10-30 minutes. A LOOK AHEAD: A very slight chance Saturday afternoon and early evening for some pesky high-based rain showers/isolated thunderstorms with little to threat for heavy rainfall. Sunday will be dry and that trend will continue through the week as high-pressure returns with high temperatures expected in the mid to upper 80's for the plains with upper 70's to low 80's along the foothills. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 800 AM FRI Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Arapahoe Current TO 800 AM FRI Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Boulder Current TO 800 AM FRI Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Broomfield Current TO 800 AM FRI Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Denver Current TO 800 AM FRI Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Douglas Current TO 800 AM FRI Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Jefferson Current TO 800 AM FRI Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder Current TO 800 AM FRI Trace (75%) to 0.2" (40%) to 0.5" (20%) LOW Douglas Current TO 800 AM FRI Trace (75%) to 0.2" (40%) to 0.5" (20%) LOW Jefferson Current TO 800 AM FRI Trace (75%) to 0.2" (40%) 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]