Flash Flood Prediction Program

Time: 309 PM Tue July 19, 2022 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR PORTIONS OF THE DISTRICT - Message 1's have been issued for portions of the District along and S of I-70 including Arapahoe, Denver, Douglas and Jefferson Counties and will be valid until 8:00pm. - A strong thunderstorm has developed over Jefferson County and is expected to move eastward through the District with the potential for heavy rainfall that may lead to excessive runoff. Upper level steering winds will move storms from W to E at around 15-20mph. - Storms are expected to move from W to E and generally remain along and S of I-70 with weaker storms northward. STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce 0.4-1.0" of heavy rain in 10-30 minutes. WORST CASE SCENARIO: Thunderstorms anchoring to the foothills or slower moving thunderstorms may result in up to 1.6" in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Jefferson County 1 Current TO 800 PM Current TO 700 PM Douglas County 1 Current TO 800 PM Current TO 700 PM Denver County 1 Current TO 800 PM Current TO 700 PM Arapahoe County 1 Current TO 800 PM Current TO 700 PM the City of Aurora 1 Current TO 800 PM Current TO 700 PM Arvada 1 Current TO 800 PM Current TO 700 PM Wheat Ridge 1 Current TO 800 PM Current TO 700 PM Lakewood 1 Current TO 800 PM Current TO 700 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 800 PM TUE 0.1" (50%) to 0.4" (20%) to 1.0" (10%) MOD Arapahoe Current TO 800 PM TUE 0.1" (90%) to 0.4" (60%) to 1.0" (30%) ISSUED Boulder Current TO 800 PM TUE 0.1" (60%) to 0.4" (30%) to 1.0" (10%) MOD Broomfield Current TO 800 PM TUE 0.1" (60%) to 0.4" (30%) to 1.0" (10%) MOD Denver Current TO 800 PM TUE 0.1" (90%) to 0.4" (60%) to 1.0" (30%) ISSUED Douglas Current TO 800 PM TUE 0.1" (95%) to 0.4" (65%) to 1.0" (30%) ISSUED Jefferson Current TO 800 PM TUE 0.1" (95%) to 0.4" (65%) to 1.0" (30%) ISSUED Foothills above 6500ft       Boulder Current TO 800 PM TUE 0.1" (60%) to 0.4" (30%) to 1.0" (10%) MOD Douglas Current TO 800 PM TUE 0.1" (100%) to 0.4" (75%) to 1.0" (40%) ISSUED Jefferson Current TO 800 PM TUE 0.1" (100%) to 0.4" (75%) to 1.0" (40%) 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]