Flash Flood Prediction Program

Time: 920 AM Mon May 3, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- COOLER TODAY WITH WIDESPREAD RAIN/MIX THIS MORNING WITH A CHANCE FOR SCATTERED RAIN SHOWERS THIS AFTERNOON/EVENING - A low-pressure system continues to churn over the region bringing widespread rain showers and mix/snow between 5,500-6,000ft with generally snow above 6,000ft at this time. As temperatures increase through the morning into the 40's lower elevations, the snow line will rise and most areas below 7,000ft will experience rain by noon. Typical rainfall amounts or melted snow equivalent is between a 0.04-0.20". - The best chance for accumulating precipitation will be until 4pm with a chance for lingering isolated rain showers after 4pm until about midnight before precipitation chances come to and end. As the evening progresses, the snow line will lower again to around 6,000ft between 8pm and midnight, although precipitation chances will be minimal at that time. After midnight skies will gradually clear with dry conditions expected into Tuesday morning. - If we get some peeks of sunshine afternoon an isolated thunderstorm cannot be completely ruled out and would have the potential to produce 0.2-0.6" in 10-30minutes. Between 0.75-2.00" of moisture has fallen over the District over the past 24 hours with isolated higher and lower amounts. Smaller creeks and streams will be running highs today as the ground is becoming saturated and additional moisture will easily produce runoff. Flash flooding is not expected. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and possibly a weak thunderstorm this afternoon will produce TR-0.20" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.20-0.40" in 30-60 minutes. WORST CASE SCENARIO: A thunderstorm is able to develop this afternoon and would be capable of producing 0.20-0.60" in 10-30 minutes. A LOOK AHEAD: An active pattern will persist over the next few days resulting in a chance for afternoon and early evening thunderstorms on Tuesday and Wednesday. High-pressure returns Thursday bringing dry conditions across the region into the weekend. LOCATION PRIME TIME 60-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Arapahoe Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Boulder Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Broomfield Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Denver Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Douglas Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Jefferson Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Foothills above 6500ft       Boulder Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Douglas Current TO 600 PM MON Trace (100%) to 0.2" (60%) to 0.4" (10%) NONE Jefferson Current TO 600 PM MON Trace (100%) to 0.2" (60%) 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]