Time: 838 AM Sun June 21, 2020 Forecaster: Justin Brooks

Heavy Precipitation Outlook
Flash Flood Prediction Program

WARM TODAY WITH A CHANCE FOR AFTERNOON/EVENING SHOWERS/THUNDERSTORMS
-Westerly upper-level flow aloft has produced a mountain wave cloud this morning which will help limit high temperatures this afternoon in the 80's over the plains with 70's along the foothills.
-A weak disturbance will move in around midday with clouds increasing behind resulting in a chance for scattered rain showers/isolated thunderstorms this afternoon, with rain chances possible until sunset this evening. Best chance for storms will be from 2-8pm with relatively quick storm motions 10-15mph which will help limit point rainfall amounts across the District.
-Skies will begin to clear after sunset as overnight lows drop into the mid to upper 50's for the plains with upper 40's to around 50 for the foothills.
STORM RAINFALL POTENTIAL AND DURATION: Showers and weak thunderstorms will produce a trace to 0.1" of rain. Moderate thunderstorms will have the potential to produce 0.1-0.2" in 10-30 minutes

WORST CASE SCENARIO: A strong thunderstorm is able to develop along a gust front/outflow boundary with the potential to produce 0.2-0.5" in 10-30 minutes.

A LOOK AHEAD: Cooler temperatures over the next couple of days in the upper 70's to low 80's. A chance for rain showers/isolated thunderstorms possible both Monday and Tuesday afternoon/early evening, although the threat for heavy rain in the District is minimal at this time.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Arapahoe 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Boulder 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Broomfield 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Denver 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Douglas 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Jefferson 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Foothills above 6500ft      
Boulder 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Douglas 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
Jefferson 200 PM TO 900 PM
Trace (30%) to 0.2" (10%) to 0.5" (5%) NONE
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.