Time: 937 AM Fri May 29, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

WARMER WITH ISOLATED AFTERNOON/EVENING THUNDERSTORMS
-Temperatures will increase today with afternoon highs topping out in the mid to upper 80's over the plains. Conditions will be dry through early afternoon then isolated thunderstorms will move through the District mid afternoon into the early evening.
-Thunderstorms will first become possible over the foothills and Palmer Divide between 1-3pm. After 3pm thunderstorms will become more likely over the plains with best chances for thunderstorm activity through about 9 or 10pm this evening.
-Thunderstorms, although isolated will be able to tap into modest surface moisture and may become moderate to strong with the potential to produce brief heavy rain. Storms will move from NW to SE at around 20mph. Strong thunderstorms may also contain large hail and gusty winds but this threat is low.
STORM RAINFALL POTENTIAL AND DURATION: 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 large strong thunderstorm or a slower moving strong thunderstorm will have the potential to produce 0.4-1.0" in 10-30 minutes and up to 1.8" in 60 minutes or less.

A LOOK AHEAD: Temperatures will cool a bit on Saturday and moisture will increase leading to a more active thunderstorm day. Thunderstorms are expected to become scattered to numerous Saturday afternoon and evening with the potential to produce heavy rainfall that may lead to excessive runoff and possibly flash flooding. A good chance for thunderstorms in the afternoon and evening with the potential for heavy rainfall will continue on Sunday.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 400 PM TO 900 PM
Trace (80%) to 0.3" (50%) to 0.6" (15%) LOW
Arapahoe 400 PM TO 900 PM
Trace (80%) to 0.3" (50%) to 0.6" (15%) LOW
Broomfield 400 PM TO 900 PM
Trace (80%) to 0.3" (50%) to 0.6" (15%) LOW
Denver 400 PM TO 900 PM
Trace (80%) to 0.3" (50%) to 0.6" (15%) LOW
Boulder 300 PM TO 900 PM
Trace (80%) to 0.3" (50%) to 0.6" (15%) LOW
Douglas 300 PM TO 900 PM
Trace (85%) to 0.3" (50%) to 0.6" (15%) LOW
Jefferson 300 PM TO 900 PM
Trace (80%) to 0.3" (50%) to 0.6" (15%) LOW
Foothills above 6500ft      
Boulder 200 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.6" (10%) LOW
Douglas 200 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.6" (10%) LOW
Jefferson 200 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.6" (10%) LOW
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.