Time: 1226 PM Tue August 13, 2024 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 2’S & MESSAGE 1’S ISSUED FOR THE DISTRICT EFFECTIVE FROM NOW PM UNTIL 11:00 PM TODAY Message 2’s, Flood Watch, have been issued for areas above 6,000ft in Boulder, Jefferson, Douglas Counties effective from NOW until 11pm this evening. Message 1’s have been issued for the remainder of the District effective from NOW until 11pm this evening. Monsoonal moisture remains over the region today. Not much change to the overall pattern will result in another chance for afternoon showers and thunderstorms with moderate to heavy rainfall. Once again, there will be a slight chance for severe weather, favoring eastern portions of the District. Dewpoints across the District have dropped only a few degrees this morning, still in the mid to upper 50s, and will only mix down to the low/mid 50s as daytime heating initiates convection over the high country west of the District. Once storms make their way into the foothills and onto the plains this afternoon, the District will have between 1.15" - 1.25" of precipitable water (PWAT) available. Combined with slow to stationary storm motion, will lead to an increased chance for localized flooding today. Hail and gusty outflow winds that reach severe thresholds will also be possible with stronger storms. Outflow boundary-driven storm initiation will be possible after the first round of storms today, with potential for lingering thunderstorms around the District remaining through the evening and into the night as an additional round of late evening storms will be possible. STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce rainfall rates of 0.3-0.8” total in 10- 30 minutes. Strong to severe thunderstorms will have the potential to produce rainfall rates of 0.8- 1.6” total of rain in 10-30 minutes. WORST CASE SCENARIO: A slow-moving strong thunderstorm or a large thunderstorm complex may result in up to 2.5” of rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME the City of Aurora 1 Current TO 1100 PM 200 PM TO 1000 PM Arapahoe County 1 Current TO 1100 PM 200 PM TO 1000 PM DIA 1 Current TO 1100 PM 200 PM TO 1000 PM Denver County 1 Current TO 1100 PM 200 PM TO 1000 PM Adams County 1 Current TO 1100 PM 200 PM TO 1000 PM Douglas County 2 Current TO 1100 PM 200 PM TO 800 PM Broomfield County 1 Current TO 1100 PM 200 PM TO 1000 PM Jefferson County 2 Current TO 1100 PM 200 PM TO 800 PM Boulder County 2 Current TO 1100 PM 200 PM TO 800 PM Arvada 1 Current TO 1100 PM 200 PM TO 1000 PM Wheat Ridge 1 Current TO 1100 PM 200 PM TO 1000 PM Lakewood 1 Current TO 1100 PM 200 PM TO 1000 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Arapahoe Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Boulder Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Broomfield Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Denver Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Douglas Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Jefferson Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Foothills above 6500ft       Boulder Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Douglas Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (25%) ISSUED Jefferson Current TO 1100 PM TUE 0.3" (75%) to 0.8" (50%) to 1.6" (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]