Flash Flood Prediction Program

Time: 454 PM Wed July 27, 2022 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S CONTINUE VALID/EVENING AND OVERNIGHT STORMS LIKELY - Message 1's have been issued for the entire District and will continue valid until midnight and possibly beyond. There are some signs that thunderstorm activity may persist and continue well past midnight into the early morning hours on Thursday resulting in Message 1's possibly being extended late this evening. - Although conditions have been quiet up to this point a cold front is expected to move through this evening and increase surface moisture from already elevated levels. Thunderstorms that develop later today and tonight will be very capable of producing heavy rainfall that may lead to excessive runoff. - Best chances for stronger thunderstorms will likely be after 7 or 8pm through about midnight. Additional rain showers and more isolated thunderstorms will remain possible into the overnight period. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers and weak thunderstorms will produce a 0.1-0.5" of rainfall. Moderate to strong thunderstorms will produce rainfall rates of 0.5-1.5" in 10-30 minutes. WORST CASE SCENARIO: A slower moving thunderstorm or anchored thunderstorm has the potential to produce up to 2.6" of heavy rainfall in 45-75 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 200 PM TO 1159 PM 700 PM TO 1130 PM Jefferson County 1 200 PM TO 1159 PM 700 PM TO 1130 PM Broomfield County 1 200 PM TO 1159 PM 700 PM TO 1130 PM Douglas County 1 200 PM TO 1159 PM 700 PM TO 1130 PM Adams County 1 200 PM TO 1159 PM 700 PM TO 1130 PM Denver County 1 200 PM TO 1159 PM 700 PM TO 1130 PM DIA 1 200 PM TO 1159 PM 700 PM TO 1130 PM Arapahoe County 1 200 PM TO 1159 PM 700 PM TO 1130 PM the City of Aurora 1 200 PM TO 1159 PM 700 PM TO 1130 PM Arvada 1 200 PM TO 1159 PM 700 PM TO 1130 PM Wheat Ridge 1 200 PM TO 1159 PM 700 PM TO 1130 PM Lakewood 1 200 PM TO 1159 PM 700 PM TO 1130 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 600 PM TO 1159 PM 0.1" (80%) to 0.5" (50%) to 1.5" (20%) ISSUED Arapahoe 600 PM TO 1159 PM 0.1" (80%) to 0.5" (50%) to 1.5" (20%) ISSUED Boulder 600 PM TO 1159 PM 0.1" (80%) to 0.5" (50%) to 1.5" (20%) ISSUED Broomfield 600 PM TO 1159 PM 0.1" (80%) to 0.5" (50%) to 1.5" (20%) ISSUED Denver 600 PM TO 1159 PM 0.1" (80%) to 0.5" (50%) to 1.5" (20%) ISSUED Douglas 600 PM TO 1159 PM 0.1" (80%) to 0.5" (50%) to 1.5" (20%) ISSUED Jefferson 600 PM TO 1159 PM 0.1" (80%) to 0.5" (50%) to 1.5" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 1159 PM WED 0.1" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Douglas Current TO 1159 PM WED 0.1" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Jefferson Current TO 1159 PM WED 0.1" (90%) to 0.5" (60%) to 1.5" (30%) 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]