Time: 953 AM Thu May 14, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

ISOLATED TO WIDELY SCATTERED AFTERNOON AND EVENING THUNDERSTORMS
-Behind a cold front that moved through last evening temperatures will be cooler today with highs in the mid 60's to around 70 over the plains. Surface moisture has increased and with the passage of an upper level disturbance isolated to widely scattered rain showers and thunderstorms can be expected this afternoon and evening.
-Shower and thunderstorm activity will develop over the Front Range foothills by around noon then storms will move onto the plains sometime between 1-2pm or shortly after. Storm motion today will be from WSW to ENE between 20-30mph. Relatively fast storm motion will help to limit point rainfall amounts but stronger storms will be capable of producing brief heavy rainfall. Typical thunderstorms will produce light to brief moderate rain, gusty winds and small hail.
-Prime time for thunderstorms will be between 1-9pm then the majority of the storm activity will have pushed E of the District. After midnight low level moisture is expected to increase further with low clouds/patchy fog and possibly some isolated areas of light rain or mist developing into daybreak Friday.
STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers and weak to moderate thunderstorms will produce a trace to 0.3" in 10-30 minutes. A strong thunderstorm will have the potential to produce 0.3-0.7" in 10-30 minutes.

WORST CASE SCENARIO: A slower moving strong thunderstorm or training of moderate/strong thunderstorm cells may result in up to 1.4" of rain in 30-60 minutes.

A LOOK AHEAD: Similar temperatures on Friday and with additional moisture and another upper level disturbance moving through scattered thunderstorms are expected Friday afternoon and evening. Some storms may become strong to severe with the potential for heavy rainfall, large hail and gusty winds. If Message 1's are not issued later today, tomorrow will most likely be the first Message 1 day of the year.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.7" (10%) LOW
Arapahoe 200 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.7" (10%) LOW
Broomfield 200 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.7" (10%) LOW
Denver 200 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.7" (10%) LOW
Boulder 100 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.7" (10%) LOW
Douglas 100 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.7" (10%) LOW
Jefferson 100 PM TO 900 PM
Trace (90%) to 0.3" (50%) to 0.7" (10%) LOW
Foothills above 6500ft      
Boulder 1200 PM TO 800 PM
Trace (95%) to 0.3" (50%) to 0.7" (5%) LOW
Douglas 1200 PM TO 800 PM
Trace (95%) to 0.3" (50%) to 0.7" (5%) LOW
Jefferson 1200 PM TO 800 PM
Trace (95%) to 0.3" (50%) to 0.7" (5%) LOW
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.