Time: 1003 AM Mon June 8, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

UNSEASONABLY COLD LOW PRESSURE SYSTEM TO IMPACT THE DISTRICT LATER TODAY AND TONIGHT
-Behind a cold front that moved through overnight temperatures will be cooler today with highs in the 70's over the plains. Conditions will be dry through the day until another, stronger cold front moves through late this afternoon or early evening producing rain showers/thunderstorms and even some late season snow for elevations above 6.5-7k overnight.
-Showers and thunderstorms will become possible as the front passes but precipitation may favor rain versus thunderstorms due to the relatively cold temperature profile. Winds will increase along and behind the front from the N to NE into the 20-30mph range with gusts to 40-50mph or more. Showers and thunderstorms will become possible after 4 or 5pm through about midnight then any thunderstorm activity should transition to rain showers for the remainder of the overnight period into Tuesday morning.
-The snow level will lower after midnight, likely dropping as low as the 6.5-7k range into Tuesday morning with minor snow accumulations expected for the foothills and higher terrain of the Palmer Divide! Heavy rainfall is not expected today but moderate rain may occur from thunderstorms with lighter rainfall rates overnight. Rainfall amounts into Tuesday morning expected to range from 0.2-0.8" over the District with isolated higher amounts possible.
STORM RAINFALL POTENTIAL AND DURATION: Showers and weak thunderstorms will produce a trace to 0.2" in 15-45 minutes. Moderate thunderstorms will have the potential to produce 0.1-0.3" in 10-30 minutes.

WORST CASE SCENARIO: A strong thunderstorm is able to develop with the potential to produce moderate to heavy rainfall of 0.2-0.6" in 10-30 minutes.

A LOOK AHEAD: Downright cold on Tuesday for June standards with highs in the 60's over the plains and 50's in the foothills along with strong NW winds of 15-30mph and gusts to 40mph or more making it feel even colder with the wind chill. Any lingering rain/snow shower activity Tuesday morning is expected to diminish before noon.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Arapahoe 600 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Douglas 600 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Adams 500 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Denver 500 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Jefferson 500 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Boulder 400 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Broomfield 400 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Foothills above 6500ft      
Douglas 600 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Jefferson 500 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
Boulder 400 PM TO 1000 AM TUE
Trace (100%) to 0.2" (75%) to 0.4" (20%) NONE
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.