Flash Flood Prediction Program

Time: 342 PM Sun July 3, 2022 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGES ISSUED FOR THE ENTIRE DISTRICT/VALID UNTIL 930 PM - Message 1's have been issued for the entire District and will be valid until 9:30pm this evening. - An outflow boundary from thunderstorms over Larimer and Weld Counties is moving southward and will enter the District in Boulder County shortly. This outflow boundary will likely act as a triggering mechanism for thunderstorms as it continues to progress southward. Stronger storms that develop on this boundary will have the potential to produce heavy rainfall that may lead to excessive runoff and possibly flash flooding. - Slower moving thunderstorms or briefly anchored thunderstorms will pose the greatest risk for extended periods of heavy rainfall. More typical storms will move from SW to NE at 15-20mph. Best chances for thunderstorms will be until 8 or 9pm. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce a trace to 0.2" of rain. Weak to moderate thunderstorms will produce 0.2-0.6" in 10-30 minutes. Strong thunderstorms will have the potential to produce 0.4-1.2" in 10-30 minutes. WORST CASE SCENARIO: An anchored strong thunderstorm or a slower moving large thunderstorm may result in up to 2.0" of rain in 60-90 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Jefferson County 1 Current TO 930 PM 430 PM TO 830 PM Broomfield County 1 Current TO 930 PM 430 PM TO 830 PM Boulder County 1 Current TO 930 PM 430 PM TO 830 PM Douglas County 1 Current TO 930 PM 430 PM TO 830 PM Adams County 1 Current TO 930 PM 430 PM TO 830 PM Denver County 1 Current TO 930 PM 430 PM TO 830 PM DIA 1 Current TO 930 PM 430 PM TO 830 PM Arapahoe County 1 Current TO 930 PM 430 PM TO 830 PM the City of Aurora 1 Current TO 930 PM 430 PM TO 830 PM Arvada 1 Current TO 930 PM 430 PM TO 830 PM Wheat Ridge 1 Current TO 930 PM 430 PM TO 830 PM Lakewood 1 Current TO 930 PM 430 PM TO 830 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 400 PM TO 900 PM 0.1" (75%) to 0.5" (40%) to 1.0" (20%) ISSUED Arapahoe 400 PM TO 900 PM 0.1" (75%) to 0.5" (40%) to 1.0" (20%) ISSUED Boulder 400 PM TO 900 PM 0.1" (90%) to 0.5" (50%) to 1.0" (25%) ISSUED Broomfield 400 PM TO 900 PM 0.1" (80%) to 0.5" (45%) to 1.0" (20%) ISSUED Denver 400 PM TO 900 PM 0.1" (75%) to 0.5" (40%) to 1.0" (20%) ISSUED Douglas 400 PM TO 900 PM 0.1" (80%) to 0.5" (45%) to 1.0" (20%) ISSUED Jefferson 400 PM TO 900 PM 0.1" (90%) to 0.5" (50%) to 1.0" (25%) ISSUED Foothills above 6500ft       Boulder 400 PM TO 900 PM 0.1" (90%) to 0.5" (50%) to 1.0" (25%) ISSUED Douglas 400 PM TO 900 PM 0.1" (90%) to 0.5" (50%) to 1.0" (25%) ISSUED Jefferson 400 PM TO 900 PM 0.1" (80%) to 0.5" (45%) to 1.0" (20%) ISSUED MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]