Flash Flood Prediction Program

Time: 1149 PM Wed May 10, 2023 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S EXTENDED UNTIL 2:00 AM THURSDAY Message 1’s have been extended until 2:00 AM Thursday. A widespread light to moderate non-thunderstorm rain continues to fall over the District and a weak to moderate thunderstorm cannot be ruled out for a couple more hours which may produce brief heavy rainfall on a ground that is becoming saturated and may result in excessive runoff keeping the Message 1’s in place. Most of the rain showers are resulting in rainfall rates of 0.1-0.4” in 30-60 minutes and is producing runoff but it is not excessive at this time and more of the nuisance variety. Should a thunderstorm develop, heavier rainfall is possible and could result in flooding. The back edge of the persistent showers and possibly an isolated thunderstorm should pass by around 2:00 AM and Messages will likely be allowed to expire but could be extended further into the overnight period. Strong thunderstorms are not expected due to cooler temperatures in the mid 40’s to around 50 currently. STORM RAINFALL POTENTIAL AND DURATION: Non-thunderstorm rain showers will produce will produce rainfall rates of 0.1-0.4" in 30-60 minutes. Weak to moderate thunderstorms produce moderate to brief heavy rainfall of 0.3-0.9" in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm is able to develop with the potential to produce rainfall rates of 0.4-1.2" in 10-30 minutes and up to 2.0" in 45-75 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Jefferson County 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Broomfield County 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Douglas County 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Adams County 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Denver County 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY DIA 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Arapahoe County 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY the City of Aurora 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Arvada 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Wheat Ridge 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY Lakewood 1 Current TO 200 AM THURSDAY Current TO 130 AM THURSDAY County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Arapahoe Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Boulder Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Broomfield Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Denver Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Douglas Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Jefferson Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Foothills above 6500ft       Boulder Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Douglas Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) ISSUED Jefferson Current TO 200 AM THU 0.1" (100%) to 0.3" (50%) to 0.9" (15%) 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]