Time: 930 AM Mon June 6, 2022 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

WETTING RAINFALL FROM THUNDERSTORMS TODAY
-An upper level disturbance and weak cool front is expected to increase thunderstorm activity today over the District. The front will have minimal impact on temperatures as they will be near normal for this time of year in the lower 80's for highs over the plains with 70's in the Front Range foothills. More importantly, surface moisture has increased allowing storms that develop today to produce wetting rainfall with minor runoff possible.
-Heavy rainfall is not expected as most storms will produce light to moderate rainfall with strong storms potentially producing brief heavy rain as well as gusty winds and possibly hail. Best chances for stronger storms today will be E of the District where moisture is deeper, but a very isolated strong storm cannot be ruled out. 1-3 rounds of showers and thunderstorms is expected to move through during the afternoon with isolated light rain showers continuing possible into the early overnight period.
-Thunderstorms will first develop over the higher terrain to the W between 11am and 1pm. Upper level steering winds will then push the storm activity onto the plains by 1-2pm. Prime time for thunderstorm activity will be between 2-10pm. Storm motions from W/WNW to E/ESE at 15-25mph will keep storms moving along and rainfall brief from a single storm. Training of thunderstorm cells may result in longer periods of rainfall. After 10pm thunderstorm activity is expected to have diminished with a few light rain showers possible through midnight.
STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" in 10-30 minutes. Moderate to briefly strong thunderstorms will have the potential to produce 0.2-0.5" in 10-30 minutes.

WORST CASE SCENARIO: Training of moderate to strong thunderstorm cells may produce rainfall amounts of up to 1.0" in 45-60 minutes.

A LOOK AHEAD: We will tack on a few degrees to high temperatures on Tuesday with readings in the low to mid 80's over the plains. Thunderstorm coverage will decrease but surface moisture will remain resulting in the storms that do develop potentially becoming moderate to strong. Best chances however, will be to the S and E of the District. A little cooler Wednesday with isolated to widely scattered thunderstorms expected.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW
Arapahoe 200 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW
Broomfield 200 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW
Denver 200 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW
Boulder 100 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW
Douglas 100 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW
Jefferson 100 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (15%) LOW
Foothills above 6500ft      
Boulder 1200 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (20%) LOW
Douglas 1200 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (20%) LOW
Jefferson 1200 PM TO 1000 PM
Trace (95%) to 0.2" (60%) to 0.5" (20%) LOW
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.
https://f2p2.udfcd.org/generator/