Time: 937 AM Mon June 12, 2023 Forecaster: Laura Smith ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 2'S HAVE BEEN ISSUED FOR THE ENTIRE DISTRICT The National Weather Service in Boulder has issued a Flood Watch for the entire District effective from 1000 AM Today, June 12th, 2023, until 1159 PM June 12th, 2023. The MHFD Message 2 will start prior to the NWS Flood Watch due to the potential for storms with heavy rainfall to enter the District before to 1000 AM. These storms have already initiated along the higher terrain foothills and will slowly progress eastward and onto the I-25 corridor today. Good upper-level support and an abundance of moisture is in place and has resulted in a good chance for widespread thunderstorms with heavy rainfall leading to localized flooding. The best time for storms to enter the western portions of the District will be between 1000AM and noon with storms likely throughout the District between 800PM - midnight. Multiple rounds of storms are likely today, leading to a Flood Watch through the evening. A chance some of these storms become severe, with large hail up to 1.5”, gusty winds 60+ mph throughout the District. The best chance for severe weather will likely be during the initial round of storms, with additional storms decreasing in intensity, however, with elevated moisture and good dynamics, even moderate rain showers will produce heavy rainfall well into the late evening hours. STORM RAINFALL POTENTIAL AND DURATION: Typical thunderstorms have the potential to produce moderate to heavy rainfall of 0.5” to 0.75” total, in 10 to 30 minutes. Strong thunderstorms have the potential to produce moderate to heavy rainfall of 0.75” to 1.75” total, in 10 to 30 minutes. WORST CASE SCENARIO: Anchored or slow-moving thunderstorms have the potential to produce up to 2.50” total in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Jefferson County 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Broomfield County 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Douglas County 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Adams County 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Denver County 2 1000 AM TO 1159 PM 1200 PM TO 800 PM DIA 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Arapahoe County 2 1000 AM TO 1159 PM 1200 PM TO 800 PM the City of Aurora 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Arvada 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Wheat Ridge 2 1000 AM TO 1159 PM 1200 PM TO 800 PM Lakewood 2 1000 AM TO 1159 PM 1200 PM TO 800 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Arapahoe 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Boulder 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Broomfield 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Denver 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Douglas 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Jefferson 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Foothills above 6500ft       Boulder 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Douglas 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) ISSUED Jefferson 1000 AM TO 1159 PM 0.5" (90%) to 0.75" (50%) to 1.75" (25%) 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]