Time: 936 AM Fri June 16, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 2’S HAVE BEEN ISSUED FOR THE ENTIRE DISTRICT Message 2’s have been issued for the entire District effective from 10am until 10pm this evening. The Message 2’s have been issued effective prior to the start time of the NWS Flood Watch as the threat for moderate to heavy rain will be possible throughout most of the day today. A few scattered rain showers are currently over the District which could help limit the potential for stronger storm development this afternoon and evening. However, good upper-level support, which will increase as the day moves on will likely produce stronger storms this afternoon and evening with widespread moderate to heavy rainfall likely across the District. The best chance for impactful showers will start at 10am this morning, with increasing chances into the afternoon and evening before chances for heavy rainfall subsides after 10pm. With today’s storms there will be a good threat for both 0.5” or more in 10-30 minutes as well as a few areas that could have persistent moderate to heavy rainfall with over 1” per hour possible in some spots. Expect Low Impact Flooding triggering with lower initial storm amounts today between 0.35-0.45” which will likely result in pooling of water as the surface remains saturated at this time. Storms may also contain large hail, gusty winds and frequent cloud-to-ground lightning. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers will produce 0.2-0.5” total, in 10-30 minutes. Moderate to heavy rain showers and thunderstorms will produce 0.5-1.5” total, in 10-30 minutes. WORST CASE SCENARIO: A stationary strong thunderstorm, or training of moderate to heavy showers/thunderstorms has the potential to produce 3.0” of rainfall in 60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Jefferson County 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Broomfield County 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Douglas County 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Adams County 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Denver County 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM DIA 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Arapahoe County 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM the City of Aurora 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Arvada 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Wheat Ridge 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM Lakewood 2 1000 AM TO 1000 PM 1200 PM TO 1000 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (50%) to 1.5" (25%) ISSUED Arapahoe 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (50%) to 1.5" (25%) ISSUED Boulder 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (50%) to 1.5" (25%) ISSUED Broomfield 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (50%) to 1.5" (25%) ISSUED Denver 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (50%) to 1.5" (25%) ISSUED Douglas 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (60%) to 1.5" (30%) ISSUED Jefferson 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (60%) to 1.5" (30%) ISSUED Foothills above 6500ft       Boulder 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (60%) to 1.5" (30%) ISSUED Douglas 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (60%) to 1.5" (30%) ISSUED Jefferson 1000 AM TO 1000 PM 0.2" (100%) to 0.5" (60%) to 1.5" (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]