Flash Flood Prediction Program

Time: 150 PM Tue August 9, 2022 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- CHANCES STARTING TO INCREASE FOR A FEW RAIN SHOWERS/ISOLATED THUNDERSTORMS TO THE EAST AND SOUTH - Dew points have struggled to mix out through the morning and remain in the low to mid 50's across the District. Sufficient daytime heating has resulted increased cloud cover to eastern and southern portions of the District at this time. - These storms could strengthen as the afternoon progresses, which has resulted in a LOW chance for Message 1's for the District. Storms are not expected to be particularly strong, however, storm motions will be slowly S/SE between 3-8mph resulting in an increased chance for a quick 0.5" in 10-30 minutes. Storms will favor areas east of I-25 and southward along the Palmer Divide. A stronger storm has the potential to produce a gust front which would also elevate chances of additional storms in the District. - Best chance for storms will be from now until 6pm with clouds gradually clearing into the later evening. Overnight lows will drop into the upper 50's to low 60's on the plains with low to mid 50's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers and weak thunderstorms will produce a trace to 0.2" of moisture. Moderate thunderstorms will have the potential to produce rainfall rates of 0.2-0.5" in 10-30 minutes. WORST CASE SCENARIO: Outflow from thunderstorms outside the District pushes additional moisture into the area and provides a triggering mechanism for strong thunderstorms with the potential to produce rainfall rates of 0.5-1.0" in 10-30 minutes and up to 1.5" in 45-60 minutes. A LOOK AHEAD: The 90's stick around into the weekend as high-pressure holds over the District. Mostly sunny and dry tomorrow with a very slight chance for a few rain showers/isolated thunderstorms along the higher terrain. Even warmer Thursday with continued dry conditions. A slight chance for afternoon rain showers/isolated thunderstorms Friday with minimal rainfall expected as most storms remain high-based resulting in a better chance for gusty winds rather than rainfall. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 700 PM TUE Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Arapahoe Current TO 700 PM TUE Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Boulder Current TO 700 PM TUE Trace (30%) to 0.2" (15%) to 0.5" (10%) LOW Broomfield Current TO 700 PM TUE Trace (30%) to 0.2" (15%) to 0.5" (10%) LOW Denver Current TO 700 PM TUE Trace (40%) to 0.2" (20%) to 0.5" (10%) LOW Douglas Current TO 700 PM TUE Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Jefferson Current TO 700 PM TUE Trace (30%) to 0.2" (15%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder Current TO 700 PM TUE Trace (30%) to 0.2" (20%) to 0.5" (10%) LOW Douglas Current TO 700 PM TUE Trace (40%) to 0.2" (20%) to 0.5" (10%) LOW Jefferson Current TO 700 PM TUE Trace (30%) to 0.2" (15%) to 0.5" (10%) 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]