Time: 833 AM Mon May 31, 2021 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- CONTINUED UNSESEASONABLY COLD WITH RAIN SHOWERS AND POSSIBLY AFTERNOON THUNDERSTORMS - Trough of low pressure will make some eastward progress today with less overall rain as the focus shifts southward but there will still be showers and possibly a thunderstorm this afternoon. Temperatures will continue to run well below seasonal averages with highs in the 50's to lower 60's over the plains. Normal high for Denver today is 78 degrees. - Light rain showers can be expected this morning with an uptick in shower activity expected by late morning and continuing through the afternoon. Thunderstorm chances will hinge upon daytime heating and if temperatures warm firmly into the 60's there will be a better chance for thunder. If temperatures remain on the cool side precipitation will likely favor a general rain. Thunderstorm chances appear highest S of I-70 at this time and in particular over Douglas County. If a thunderstorm does manage to develop moderate to brief heavy rainfall can be expected as abundant moisture remains in place. - Rain shower and any potential thunderstorm activity is expected to diminish by sunset or shortly after with dry conditions for the overnight period. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce a trace to 0.2" of rain in 30-60 minutes. Weak thunderstorms will have to produce 0.2-0.6" in 10-30 minutes. WORST CASE SCENARIO: Temperatures warm well into the 60's resulting in moderate to strong thunderstorms with the potential to produce 0.4-1.0" of heavy rain in 10-30 minutes. A LOOK AHEAD: Warmer and drier air will begin to move into the District on Tuesday. More sunshine to start the day will allow temperatures to warm into the 70's over the plains with 60's in the foothills. A weak disturbance moving in from the NW will result in isolated to widely scattered afternoon thunderstorms. Most storms will produce light to briefly moderate rain. Heavy rainfall is not expected at this time. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 800 PM MON Trace (100%) to 0.2" (50%) to 0.6" (10%) LOW Arapahoe Current TO 800 PM MON Trace (100%) to 0.2" (50%) to 0.6" (10%) LOW Boulder Current TO 800 PM MON Trace (100%) to 0.2" (50%) to 0.6" (10%) LOW Broomfield Current TO 800 PM MON Trace (100%) to 0.2" (50%) to 0.6" (10%) LOW Denver Current TO 800 PM MON Trace (100%) to 0.2" (50%) to 0.6" (10%) LOW Douglas Current TO 800 PM MON Trace (100%) to 0.2" (75%) to 0.6" (25%) MOD Jefferson Current TO 800 PM MON Trace (100%) to 0.2" (60%) to 0.6" (20%) LOW Foothills above 6500ft       Boulder Current TO 800 PM MON Trace (100%) to 0.2" (50%) to 0.6" (10%) LOW Douglas Current TO 800 PM MON Trace (100%) to 0.2" (80%) to 0.6" (30%) MOD Jefferson Current TO 800 PM MON Trace (100%) to 0.2" (75%) to 0.6" (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]