Time: 850 AM Mon July 27, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

GENERALLY DRY WITH A FEW ISOLATED THUNDERSTORMS POSSIBLE FAVORING THE HIGHER TERRAIN
-Drier air is moving into the District today as the monsoon moisture has been pushed southward temporarily. The lower moisture levels and a warm layer of air aloft is expected to result in generally dry conditions although isolated rain showers and thunderstorms cannot be ruled out, mainly in and near the foothills.
-Although the chances for thunderstorms is low the storms that do manage to develop will have the potential to produce moderate to brief heavy rainfall. Storm motions from NW to SE or N to S at around 10mph will keep the storms that form over the mountains/foothills to remain over the higher terrain. Outflow from foothill storms may be able to generate additional activity over the plains late in the afternoon.
-Temperatures will be below normal with highs topping out in the low to mid 80's over the plains. Normal high for Denver today is 90 degrees.
STORM RAINFALL POTENTIAL AND DURATION: Isolated rain showers and weak thunderstorms will produce a trace to 0.2". Moderate thunderstorms will have the potential to produce 0.2-0.6" in 10-30 minutes.

WORST CASE SCENARIO: A strong thunderstorm is able to develop with the potential to produce 0.4-1.2" in 10-30 minutes.

A LOOK AHEAD: On Tuesday a passing upper level disturbance will draw the monsoon moisture northward again and help to act as a focus for storms with scattered to widespread showers and thunderstorms expected in the afternoon and evening. Thunderstorms will be capable of producing heavy rainfall that may lead to excessive runoff and possibly flash flooding.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 300 PM TO 900 PM
Trace (25%) to 0.1" (15%) to 0.3" (5%) NONE
Arapahoe 300 PM TO 900 PM
Trace (25%) to 0.1" (15%) to 0.3" (5%) NONE
Boulder 300 PM TO 900 PM
Trace (25%) to 0.1" (15%) to 0.3" (5%) NONE
Broomfield 300 PM TO 900 PM
Trace (25%) to 0.1" (15%) to 0.3" (5%) NONE
Denver 300 PM TO 900 PM
Trace (25%) to 0.1" (15%) to 0.3" (5%) NONE
Douglas 300 PM TO 900 PM
Trace (25%) to 0.1" (15%) to 0.3" (5%) NONE
Jefferson 300 PM TO 900 PM
Trace (25%) to 0.1" (15%) to 0.3" (5%) NONE
Foothills above 6500ft      
Boulder 200 PM TO 900 PM
Trace (65%) to 0.2" (30%) to 0.6" (10%) LOW
Douglas 200 PM TO 900 PM
Trace (65%) to 0.2" (30%) to 0.6" (10%) LOW
Jefferson 200 PM TO 900 PM
Trace (65%) to 0.2" (30%) to 0.6" (10%) LOW
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.