Flash Flood Prediction Program

Time: 843 AM Sun July 23, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- HOT TODAY WITH A SLIGHT CHANCE FOR LATER AFTERNOON/EVE HIGH-BASED SHOWERS/ISOLATED THUNDERSTORMS Very little overall change to the upper-level pattern as north to northwesterly flow aloft continues to dominate over the region this weekend. Dew points have decreased this morning and will likely mix out through the rest of the day, dropping into the low to mid 40’s, with possibly a few upper 30’s for areas west of I-25. These lower dewpoints suggest that any storm development late this afternoon and into the evening will remain high-based bringing minimal rainfall for most areas. The best chance for storm development withing the District will be between 4-9pm. Storm motions will once again be NW to SE between 15-25mph, effectively limiting any point rainfall amounts. A few storms could produce some lightning with a slight chance for a few pockets of moderate rainfall, however any shower activity today should remain brief. Skies will clear after sunset today with overnight lows well in the 60’s on the plains with upper 50’s to around 60 degrees along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce a TR-0.10” total, in 10-30 minutes. A weak to moderate showers/isolated thunderstorm will produce 0.1-0.3” total in 10-30 minutes. WORST CASE SCENARIO: A stronger thunderstorm is able to develop and will have the potential to produce up to 0.6” total, in 45-60 minutes. A LOOK AHEAD: Similar conditions are in place for tomorrow with winds picking up at the surface during the day leading to breezy conditions. A very slight chance for another round of high-based showers/isolated thunderstorms tomorrow, with minimal, if any heavy rainfall threat as high temperatures remain nearly 100 degrees. Not much change Tuesday with another chance for afternoon/evening high-based showers/isolated thunderstorms, with most precipitation struggling to reach the surface as high temps continue in the mid to upper 90’s. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 400 PM TO 900 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Arapahoe 400 PM TO 900 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Boulder 400 PM TO 900 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Broomfield 400 PM TO 900 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Denver 400 PM TO 900 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Douglas 400 PM TO 900 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Jefferson 400 PM TO 900 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Foothills above 6500ft       Boulder 400 PM TO 900 PM Trace (30%) to 0.1" (20%) to 0.3" (10%) NONE Douglas 400 PM TO 900 PM Trace (30%) to 0.1" (20%) to 0.3" (10%) NONE Jefferson 400 PM TO 900 PM Trace (30%) to 0.1" (20%) to 0.3" (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]