Flash Flood Prediction Program

Time: 931 AM Sat June 10, 2023 Forecaster: Laura Smith ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- SCATTERED TO ISOLATED THUNDERSTORM ACTIVITY IS EXPECTED TODAY A blocking pattern is in place over the continental US, positioning southerly upper-level flow across Colorado while low level moisture east of the Continental Divide remains heightened from yesterday’s storms. This morning will be mostly sunny across the Front Range Urban Corridor followed by high temperatures in the upper 70s to low 80s, dew points in the mid to upper 40s, through the afternoon and evening. Forecast soundings reveal bulk shear around 20-25 kt, and PWAT values between 0.55” to 0.65”. These conditions will support an unstable environment favoring weakly organized thunderstorms by the mid to late afternoon. Thunderstorms have the potential to produce moderate to briefly heavy rainfall of 0.25” to 0.50” in 10-30 minutes. Storms are expected to exit the Front Range Urban Corridor by the mid evening hours, followed by a cold front overnight. STORM RAINFALL POTENTIAL AND DURATION: Typical thunderstorms will produce a TR to 0.25” in 10-30 minutes. A strong thunderstorm could produce 0.25” to 0.50” in 10-30 minutes. WORST CASE SCENARIO: Anchored or slow-moving thunderstorms have the potential to produce 0.50”-0.75” in 45-60 minutes. A LOOK AHEAD: Tomorrow will be considerably active with scattered to widespread clustered thunderstorms across the Front Range Urban Corridor. Strong storms are expected to develop mid-afternoon, persisting throughout the evening and early overnight hours. Storms will dissipate and exit the area after midnight. Looking ahead, the upper-level pattern remains in place through early next week, with high temperatures in the upper 60s to 70s and afternoon to evening thunderstorms, possible locally heavy rainfall, and severe conditions. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Arapahoe 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Boulder 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Broomfield 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Denver 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Douglas 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Jefferson 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Foothills above 6500ft       Boulder 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Douglas 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Jefferson 200 PM TO 800 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]