Flash Flood Prediction Program

Time: 857 AM Thu August 10, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARM SUNNY WITH A SLIGHT CHANCE FOR HIGH-BASED AFTERNOON/EARLY EVE SHOWERS/THUNDERSTORMS Westerly upper-level flow will dominate the region today as a weak ridge of high-pressure sits towards our south. This will lead to warm temperatures today in the mid to upper 80s across the plains with low to mid 80s along the foothills. A slight chance for widely scattered afternoon showers/isolated thunderstorms between 2-8pm with skies quickly clearing this evening. Storms today will likely be high based with minimal rainfall as temperature/dew point spreads likely between 40-50 degrees this afternoon as dew points drop into the low to mid 40s. If dew points struggle to mix out today, a slight chance for a few meaningful thunderstorms, favoring eastern portions of the District through the afternoon and evening. Mild and dry conditions are expected through the overnight with temperatures dropping into the low 60s on the plains with mid to upper 50s along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers/weak thunderstorms will produce a trace-0.20” total in 10-30 minutes. A weak to moderate thunderstorm will produce 0.20-0.40” total in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm, or training of moderate thunderstorms has the potential to produce 0.40-0.80” total in under 60 minutes. A LOOK AHEAD: Similar conditions will be in place tomorrow as high temperatures reach around 90 degrees. A slightly better chance for afternoon/eve showers/isolated thunderstorms, with a couple of rounds possible. A better chance for showers/isolated thunderstorms Saturday, possibly with a LOW chance for Message 1’s to be issued as an uptick in moisture at the surface and upper level is likely. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM Trace (40%) to 0.2" (20%) to 0.4" (10%) NONE Arapahoe 200 PM TO 800 PM Trace (40%) to 0.2" (20%) to 0.4" (10%) NONE Boulder 200 PM TO 800 PM Trace (30%) to 0.2" (15%) to 0.4" (5%) NONE Broomfield 200 PM TO 800 PM Trace (30%) to 0.2" (15%) to 0.4" (5%) NONE Denver 200 PM TO 800 PM Trace (30%) to 0.2" (15%) to 0.4" (5%) NONE Douglas 200 PM TO 800 PM Trace (40%) to 0.2" (20%) to 0.4" (10%) NONE Jefferson 200 PM TO 800 PM Trace (30%) to 0.2" (15%) to 0.4" (5%) NONE Foothills above 6500ft       Boulder 200 PM TO 800 PM Trace (40%) to 0.2" (20%) to 0.4" (10%) NONE Douglas 200 PM TO 800 PM Trace (40%) to 0.2" (20%) to 0.4" (10%) NONE Jefferson 200 PM TO 800 PM Trace (40%) to 0.2" (20%) to 0.4" (10%) 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]