Time: 846 AM Mon June 22, 2020 Forecaster: Justin Brooks

Heavy Precipitation Outlook
Flash Flood Prediction Program

COOLER TODAY WITH A CHANCE FOR RAIN/ISOLATED THUNDERSTORM THIS AFTERNOON AND EVENING
-Continued NW upper-level flow will result in slightly cooler high temperatures today which will reach the upper 70's to around 80 across the District. Mostly sunny skies this morning with clouds increasing this afternoon bringing a chance for rain showers/isolated thunderstorms this afternoon and evening favoring portions of the southern District.
-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. With a slight chance for lingering rain showers until 1-3am Tuesday morning before skies begin to clear out.
-Surface moisture will be modest through the early afternoon with dew points in the mid 40's. However, models indicate decent upper-level support today along the Palmer Divide which could provide enhanced lift along southern portions of the District and has the potential to initiate stronger storms with moderate to heavy rain. Storm motions will be relatively fast from W/NW to E/SE between 10-15mph, which will help limit point rainfall amounts. Although a slower moving storm that formed along an outflow boundary has increased potential for heavy rainfall.
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 0.2-0.5" in 10-30 minutes

WORST CASE SCENARIO: A large strong thunderstorm or a slower moving/stationary thunderstorm will have the potential to produce 0.5-0.8" in 10-30 minutes and up to 1.5" in 60 minutes or less.

A LOOK AHEAD: High temperatures remain cool Tuesday in the low 80's across the plains with mid to upper 70's along the foothills. A chance for rain showers/isolated thunderstorms will be possible each day this week, with chances increases Thursday and Friday. Temperatures will begin to be more seasonal after tomorrow, back into the low 90's for both Wednesday and Thursday.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
Arapahoe 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
Boulder 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
Broomfield 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
Denver 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
Douglas 200 PM TO 1000 PM
Trace (50%) to 0.2" (40%) to 0.5" (20%) LOW
Jefferson 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
Foothills above 6500ft      
Boulder 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
Douglas 200 PM TO 1000 PM
Trace (50%) to 0.2" (40%) to 0.5" (20%) LOW
Jefferson 200 PM TO 1000 PM
Trace (50%) to 0.2" (30%) to 0.5" (10%) LOW
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.