Flash Flood Prediction Program

Time: 147 AM Sat June 3, 2023 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S WILL BE ALLOWED TO EXPIRE AT 2:00 AM Message 1’s will be allowed to expire at 2:00 AM as the thunderstorms and heavier rain showers have dissipated. Light to moderate rain showers will continue possible for the remainder of the overnight period into daybreak Saturday morning. Rain showers and isolated to widely scattered thunderstorms are expected to increase in coverage as the morning wears on Saturday “upslope” flow will be in place along the I-25 corridor. Moisture will increase further and thunderstorms will be capable of producing heavy rainfall that may lead to excessive runoff and possibly flash flooding. If temperatures remain too cool in the lower 60's the precipitation may favor light to moderate rain showers versus heavy thunderstorm rain. Either way a wet day is in store for Saturday and Message 1’s will likely be issued by noon or before. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and possibly a weak thunderstorms will produce rainfall rates of a trace to 0.3" in 10-30 minutes. WORST CASE SCENARIO: A moderate to strong thunderstorm is able to develop and may result in rainfall rates of 0.3-0.8" in 10-30 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 200 AM Current TO 100 AM SUNDAY Jefferson County 1 Current TO 200 AM Current TO 100 AM SUNDAY Broomfield County 1 Current TO 200 AM Current TO 100 AM SUNDAY Douglas County 1 Current TO 200 AM Current TO 100 AM SUNDAY Adams County 1 Current TO 200 AM Current TO 100 AM SUNDAY Denver County 1 Current TO 200 AM Current TO 100 AM SUNDAY DIA 1 Current TO 200 AM Current TO 100 AM SUNDAY Arapahoe County 1 Current TO 200 AM Current TO 100 AM SUNDAY the City of Aurora 1 Current TO 200 AM Current TO 100 AM SUNDAY Arvada 1 Current TO 200 AM Current TO 100 AM SUNDAY Wheat Ridge 1 Current TO 200 AM Current TO 100 AM SUNDAY Lakewood 1 Current TO 200 AM Current TO 100 AM SUNDAY County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE Arapahoe Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE Boulder Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE Broomfield Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE Denver Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE Douglas Current TO 900 AM SAT Trace (100%) to 0.1" (80%) to 0.3" (40%) NONE Jefferson Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE Foothills above 6500ft       Boulder Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE Douglas Current TO 900 AM SAT Trace (100%) to 0.1" (80%) to 0.3" (40%) NONE Jefferson Current TO 900 AM SAT Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]