Time: 901 AM Sun May 31, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

A LITTLE WARMER WITH ISOLATED TO WIDELY SCATTERED AFTERNOON THUNDERSTORMS
-Temperatures will warm a few degrees today, mainly due to more sunshine through the early afternoon. Highs will top out in the upper 80's to around 90 over the plains.
-Modest surface moisture in tandem with daytime heating will begin to generate thunderstorm activity over the foothills by around noon or shortly after. Thunderstorms will become possible over the plains between 1-3pm. Isolated to widely scattered thunderstorms are then expected into the early evening. Prime time for thunderstorms today is between 2-9pm.
-Typical weak to moderate thunderstorms will produce light to brief moderate rain. Strong thunderstorms will have the potential for heavy rainfall and hail. Storms motions will be relatively slow today from WSW to ENE at around 10mph and some storms may try to anchor near the foothills. The slow storm motions and modest moisture levels will result in stronger thunderstorms having the potential to produce excessive runoff that may lead to flash flooding.
STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce a trace to 0.3" of rainfall in 10-30 minutes. Strong thunderstorms will have the potential to produce 0.3-0.9" of rain in 10-30 minutes.

WORST CASE SCENARIO: An anchored strong thunderstorm may produce up to 1.8" of rain in 45-60 minutes.

A LOOK AHEAD: More of the same moving forward with daily chances for afternoon and evening thunderstorms through the end of the work week with the potential to produce moderate and heavy rainfall.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 900 PM
Trace (80%) to 0.3" (40%) to 0.9" (15%) MOD
Arapahoe 200 PM TO 900 PM
Trace (80%) to 0.3" (40%) to 0.9" (15%) MOD
Boulder 200 PM TO 900 PM
Trace (80%) to 0.3" (40%) to 0.9" (15%) MOD
Broomfield 200 PM TO 900 PM
Trace (80%) to 0.3" (40%) to 0.9" (15%) MOD
Denver 200 PM TO 900 PM
Trace (80%) to 0.3" (40%) to 0.9" (15%) MOD
Douglas 200 PM TO 900 PM
Trace (80%) to 0.3" (40%) to 0.9" (15%) MOD
Jefferson 200 PM TO 900 PM
Trace (80%) to 0.3" (40%) to 0.9" (15%) MOD
Foothills above 6500ft      
Boulder 100 PM TO 900 PM
Trace (95%) to 0.3" (60%) to 0.9" (15%) MOD
Douglas 100 PM TO 900 PM
Trace (95%) to 0.3" (60%) to 0.9" (15%) MOD
Jefferson 100 PM TO 900 PM
Trace (95%) to 0.3" (60%) to 0.9" (15%) MOD
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.