Time: 944 AM Sat May 2, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

COOLER WITH AFTERNOON SHOWERS/THUNDERSTORMS, STRONG STORMS POSSIBLE?
-Forecast is a little tricky today due to cloud cover and the impact it will have on temperatures and in turn the strength of thunderstorms this afternoon and evening. Cloudy skies this morning are expected to become partly cloudy by around noon or shortly after. But, if persistent cloud cover remains in place temperatures likely only warm into the 60's with the result being weak to moderate thunderstorms. If clouds clear out and temperatures warm firmly into the 70's then thunderstorms may become strong with gusty winds, hail and brief moderate to heavy rainfall. Either way we are expecting to experience some shower activity today.
-Prime time for showers and thunderstorms over the District will be between 2-10pm. Storms will be fast moving from WSW to ENE at around 40mph which will help to limit point rainfall amounts from a single storm. If a strong thunderstorm develops, hail will be the most likely outcome but brief heavy rainfall cannot be ruled out with surface dew points in the mid to upper 40's resulting in a low Message potential today. Greatest threat for strong storms today looks to be NE of the District where clouds are thinning currently.
-After 10pm rain shower activity should have moved east of the District with dry conditions for the overnight period.
STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.2-0.6" in 10-30 minutes.

WORST CASE SCENARIO: A slow moving strong thunderstorm or training of thunderstorm cells may result in up to 1.2" of rain in 30-60 minutes.

A LOOK AHEAD: Another system will skirt across the CO/WY border area on Sunday with the best chances for more numerous thunderstorms N of the District. Isolated afternoon and evening thunderstorms will still be possible over the District but with best moisture and lift remaining N, rainfall is expected to be relatively light.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 1000 PM
Trace (95%) to 0.2" (50%) to 0.6" (10%) LOW
Arapahoe 200 PM TO 1000 PM
Trace (90%) to 0.2" (50%) to 0.6" (10%) LOW
Boulder 200 PM TO 1000 PM
Trace (100%) to 0.2" (60%) to 0.6" (15%) LOW
Broomfield 200 PM TO 1000 PM
Trace (95%) to 0.2" (50%) to 0.6" (10%) LOW
Denver 200 PM TO 1000 PM
Trace (95%) to 0.2" (50%) to 0.6" (10%) LOW
Douglas 200 PM TO 1000 PM
Trace (90%) to 0.2" (50%) to 0.6" (10%) LOW
Jefferson 200 PM TO 1000 PM
Trace (95%) to 0.2" (50%) to 0.6" (10%) LOW
Foothills above 6500ft      
Boulder 100 PM TO 1000 PM
Trace (100%) to 0.2" (60%) to 0.6" (15%) LOW
Douglas 100 PM TO 1000 PM
Trace (90%) to 0.2" (50%) to 0.6" (10%) LOW
Jefferson 100 PM TO 1000 PM
Trace (95%) to 0.2" (50%) to 0.6" (10%) LOW
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.