Time: 409 PM Tue June 25, 2019 Forecaster: Alan Smith

Heavy Precipitation Outlook
Flash Flood Prediction Program

WARM WITH ISOLATED HIGH-BASED THUNDERSTORMS
-Weak high pressure building into the District will result in slightly warmer temperatures compared to yesterday with highs in the low to mid 80s. Mostly sunny skies early will give way to mostly cloudy skies this afternoon.
-A minor upper level disturbance will approach the District from the west early this afternoon, resulting in isolated high-based showers and thunderstorms, favoring western and southern areas. Moisture will be lacking at the low and mid levels of the atmosphere, therefore only light rainfall amounts are expected.
-Storms today will move from west to east at 12-17mph and produce gusty winds and occasional cloud-to-ground lightning. Storm activity will quickly shut down this evening with the loss of daytime heating.
STORM RAINFALL POTENTIAL AND DURATION: Typical showers and weak thunderstorms will produce rainfall amounts of TR-0.1" in 10-30 minutes. A strong thunderstorm could produce rainfall of 0.1-0.3" in 10-30 minutes.

WORST CASE SCENARIO: Training of thunderstorm cells results in rainfall of up to 0.6" in 30-60 minutes.

A LOOK AHEAD: High pressure will strengthen over the second half of the week, resulting in progressively hotter and drier conditions. On Wednesday, isolated high-based thunderstorms are expected once again with minimal rainfall. Thursday and Friday are looking generally dry on the plains at this time while a stray thunderstorm can't be ruled out over the foothills or Palmer Divide either day. Highs on the plains will range from the upper 80s on Wednesday to the low/mid 90s on Thursday and Friday.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 800 PM
Trace (75%) to 0.1" (35%) to 0.3" (10%) NONE
Arapahoe 200 PM TO 800 PM
Trace (75%) to 0.1" (35%) to 0.3" (10%) NONE
Boulder 200 PM TO 800 PM
Trace (80%) to 0.1" (35%) to 0.3" (10%) NONE
Broomfield 200 PM TO 800 PM
Trace (75%) to 0.1" (35%) to 0.3" (10%) NONE
Denver 200 PM TO 800 PM
Trace (75%) to 0.1" (35%) to 0.3" (10%) NONE
Douglas 200 PM TO 900 PM
Trace (85%) to 0.1" (40%) to 0.3" (10%) NONE
Jefferson 200 PM TO 800 PM
Trace (85%) to 0.1" (40%) to 0.3" (10%) NONE
Foothills above 6500ft      
Boulder 100 PM TO 800 PM
Trace (90%) to 0.1" (45%) to 0.3" (10%) NONE
Douglas 100 PM TO 900 PM
Trace (90%) to 0.1" (45%) to 0.3" (10%) NONE
Jefferson 100 PM TO 800 PM
Trace (90%) to 0.1" (45%) to 0.3" (10%) NONE
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.