Time: 932 AM Tue June 13, 2023 Forecaster: Laura Smith ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- ANOTHER ROUND OF SLOW-MOVING THUNDERSTORMS EXPECTED TODAY Upper-level flow is still blocked across the US today, but the pattern is expected to begin breaking down and shifting east tonight. Locally, moisture values remain elevated from heavy rain over the last few days. This morning will be partly cloudy with patches of fog across the District followed by high temperatures in the mid to upper 60s, dew points in the upper 40s to low 50s. Forecast soundings reveal mid to upper level shear around 10-20 kt, and precipitable water values (PWAT) values between 0.65” to 0.75”. These ingredients support slow moving scattered to widespread precipitation, although much less than previous days. Rain showers will develop across the area late this morning, impacting the District through the afternoon, and are expected to exit the District by the late evening hours. STORM RAINFALL POTENTIAL AND DURATION: Typical storms have the potential to produce moderate to briefly heavy rainfall of 0.25” to 0.50” in 10 to 30 minutes. Strong thunderstorms have the potential to produce moderate to heavy rainfall of 0.50” to 1.00” in 10 to 30 minutes. WORST CASE SCENARIO: Anchored or slow-moving thunderstorms have the potential to produce 1.00” to 1.75” in 45 to 60 minutes. A LOOK AHEAD: Looking ahead, the upper-level pattern will finally exit the region tomorrow, followed by a more seasonal pattern of isolated afternoon showers and thunderstorms. Tomorrow morning will be mostly sunny followed by highs in the mid to upper 70s and a round of afternoon showers and thunderstorms. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Arapahoe 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Boulder 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Broomfield 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Denver 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Douglas 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Jefferson 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Foothills above 6500ft       Boulder 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Douglas 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH Jefferson 1100 AM TO 500 PM 0.25" (75%) to 0.5" (50%) to 1" (25%) HIGH MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]