Flash Flood Prediction Program

Time: 940 AM Thu September 15, 2022 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS - An upper-level disturbance, rich with moisture from the remnants of tropical cyclone Kay, is propagating across the intermountain west supporting a favorable environment for scattered showers and thunderstorms across the District. - High temperatures today will reach the upper 70s to low 80s, with surface dew points in the upper 40s to low 50s. Moderate rainfall is expected, with a chance for stronger storms to produce small hail, wind gusts up to 60mph, and briefly heavy rainfall. - As showers and thunderstorms taper off into the evening, skies will gradually clear through the overnight with cool and mild conditions expected into Friday. Overnight lows will drop into the mid 50's on the plains with upper 30's to low 40's across the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers/isolated thunderstorms will produce a trace to 0.2"-0.4" in 10-30 minutes. A moderate to strong thunderstorms can produce 0.4-0.8" in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm or training of thunderstorm cells has the potential to produce up to 0.8"-1.0" in 10-30 minutes. A LOOK AHEAD: Tomorrow will be a bit warmer with a slight chance for afternoon to evening showers and thunderstorms. Highs will reach the upper 70s to low 80s. The warming trend continues Saturday with high temperatures reaching the mid 80s under clear skies. High pressure ridging will build across the Great Plains next week, transporting warm, dry air into the state. As a result, Sunday and Monday will be sunny and uneventful with highs reaching the upper 80s to low 90s. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Douglas 100 PM TO 800 PM Trace (80%) to 0.4" (40%) to 0.8" (20%) MOD Arapahoe 1200 PM TO 800 PM Trace (80%) to 0.4" (40%) to 0.8" (20%) MOD Denver 1200 PM TO 800 PM Trace (80%) to 0.4" (40%) to 0.8" (20%) MOD Adams 1100 AM TO 800 PM Trace (80%) to 0.4" (40%) to 0.8" (20%) MOD Broomfield 1100 AM TO 800 PM Trace (80%) to 0.4" (40%) to 0.8" (20%) MOD Jefferson 1100 AM TO 800 PM Trace (80%) to 0.4" (40%) to 0.8" (20%) MOD Boulder 1000 AM TO 800 PM Trace (80%) to 0.4" (40%) to 0.8" (20%) MOD Foothills above 6500ft       Boulder 1000 AM TO 800 PM Trace (90%) to 0.4" (60%) to 0.8" (30%) MOD Douglas 1000 AM TO 800 PM Trace (90%) to 0.4" (60%) to 0.8" (30%) MOD Jefferson 1000 AM TO 800 PM Trace (90%) to 0.4" (60%) to 0.8" (30%) MOD MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]