Time: 1244 PM Fri May 26, 2023 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR THE ENTIRE DISTRICT Message 1’s have been issued for the entire District and will be valid until 9:00pm this evening. Daytime heating is already starting to generate thunderstorm activity over the foothills and storms will begin to move over the plains over the next few hours. Surface moisture is abundant with dew points currently in the lower 50’s which will be fuel for thunderstorms this afternoon. Stronger thunderstorms will be capable of producing heavy rainfall that may lead to excessive runoff and possibly flash flooding. Strong thunderstorms will also contain large hail, frequent cloud-to-ground lightning and gusty winds. 1-2 rounds of thunderstorms are expected through the course of the afternoon. Typical thunderstorms will move from SW to NE at around 15mph but stronger storms may move more slowly or erratically. After 8 or 9pm the thunderstorm activity is expected to have pushed to the east of the District with possibly a few lingering lighter rain showers persisting into the late evening. STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.4-1.0” in 10-30 minutes. WORST CASE SCENARIO: A slower moving strong thunderstorm or a large thunderstorm complex may result in up to 1.8” of rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Lakewood 1 1230 PM TO 900 PM 130 PM TO 800 PM Wheat Ridge 1 1230 PM TO 900 PM 130 PM TO 800 PM the City of Aurora 1 1230 PM TO 900 PM 130 PM TO 800 PM DIA 1 1230 PM TO 900 PM 130 PM TO 800 PM Arapahoe County 1 1230 PM TO 900 PM 130 PM TO 800 PM Denver County 1 1230 PM TO 900 PM 130 PM TO 800 PM Adams County 1 1230 PM TO 900 PM 130 PM TO 800 PM Douglas County 1 1230 PM TO 900 PM 130 PM TO 800 PM Broomfield County 1 1230 PM TO 900 PM 130 PM TO 800 PM Jefferson County 1 1230 PM TO 900 PM 130 PM TO 800 PM Boulder County 1 1230 PM TO 900 PM 130 PM TO 800 PM Arvada 1 1230 PM TO 900 PM 130 PM TO 800 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 100 PM TO 900 PM 0.1" (90%) to 0.5" (60%) to 1" (30%) ISSUED Arapahoe 100 PM TO 900 PM 0.1" (90%) to 0.5" (60%) to 1" (30%) ISSUED Boulder 100 PM TO 900 PM 0.1" (90%) to 0.5" (50%) to 1" (20%) ISSUED Broomfield 100 PM TO 900 PM 0.1" (90%) to 0.5" (50%) to 1" (20%) ISSUED Denver 100 PM TO 900 PM 0.1" (90%) to 0.5" (55%) to 1" (20%) ISSUED Douglas 100 PM TO 900 PM 0.1" (90%) to 0.5" (60%) to 1" (30%) ISSUED Jefferson 100 PM TO 900 PM 0.1" (90%) to 0.5" (50%) to 1" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 900 PM FRI 0.1" (95%) to 0.5" (65%) to 1" (30%) ISSUED Douglas Current TO 900 PM FRI 0.1" (95%) to 0.5" (65%) to 1" (30%) ISSUED Jefferson Current TO 900 PM FRI 0.1" (95%) to 0.5" (65%) to 1" (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]