Time: 952 AM Sun June 30, 2019 Forecaster: Justin Brooks

Heavy Precipitation Outlook
Flash Flood Prediction Program

ANOTHER WARM DAY WITH A CHANCE FOR SHOWERS/THUNDERSTORMS THIS AFTERNOON/EVENING
-As high-pressure continues to break down over the region, an upper level disturbance from the W/SW will move over northeastern Colorado resulting in a good chance for showers/thunderstorms this afternoon and evening. Sunny skies early with clouds increasing throughout the day with afternoon highs in the upper 80's to low 90's across the District.
-Thunderstorms will develop over the foothills by midday, before spreading out onto the plains this afternoon. Storm motions will be from W/SW to E/NE at 12-17mph with the best chance for storms between 1:00-8:00pm.
-With sufficient upper level support in place across the region this afternoon and dew points in the mid to upper 40's, storms will have a slight chance to become severe with hail up to 1", gusty winds and brief heavy rain. Storm activity will taper off by sunset due to the loss of daytime heating and a more stable atmosphere behind the upper level disturbance.
STORM RAINFALL POTENTIAL AND DURATION: Typical weak to moderate thunderstorms will produce rainfall amounts of Trace-0.3" in 10-30 minutes. Moderate to strong thunderstorms will be capable of producing rainfall of 0.3-0.7" in 10-30 minutes.

WORST CASE SCENARIO: A severe thunderstorm, or training of thunderstorms will produce 1.4" in 60 minutes.

A LOOK AHEAD: A similar pattern is in store next week as westerly upper level winds to our north, and sufficient surface moisture, brings a chance for afternoon showers/thunderstorms throughout the week, with the best chances for storm activity on Monday and Tuesday, along with slightly cooler temperatures in the 80's with temperatures increasing to the low 90's by Independence Day.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Arapahoe 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Boulder 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Broomfield 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Denver 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Douglas 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Jefferson 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Foothills above 6500ft      
Boulder 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Douglas 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
Jefferson 100 PM TO 800 PM
Trace (80%) to 0.3" (40%) to 0.7" (20%) MOD
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.