Time: 1015 AM Fri May 10, 2019 Forecaster: Justin Brooks

Heavy Precipitation Outlook
Flash Flood Prediction Program

COOL TODAY WITH A CHANCE FOR RAIN/ISOLATED THUNDERSTORM THIS AFTERNOON/EVENING
-Scattered showers and thunderstorms will initially develop by early afternoon, with additional rounds of showers possible into the evening. The strength of thunderstorms will largely depend on how much daytime heating occurs due to areas of cloud cover this morning. Short range models indicate clearing skies later this morning, which could potentially allow for enough clearing to support the development of an isolated stronger thunderstorm.
-A cool day today with high temperatures only reaching the mid to upper 50's across the District as residual upper level support remains in place resulting in a chance for an isolated afternoon/early evening thunderstorm with lingering rain showers this evening before tapering off by 8-10pm.
-Typical showers and storms will move to the E at 15-25mph and produce light to moderate rainfall. However, if strong thunderstorms manage to develop then brief heavy rainfall will be possible. Hail of 0.5" in diameter or more will also be possible under stronger storms if they develop. The best chance of storms will be 1-5pm, but isolated to scattered light showers will continue until 8-10pm, clearing from west to east.
STORM RAINFALL POTENTIAL AND DURATION: Showers and a weak thunderstorm will produce a TR-0.2" in 10-30 minutes. A strong isolated thunderstorm will produce 0.1-0.4" in 10-30 minutes.

WORST CASE SCENARIO: Training of showers/thunderstorms produce up to 0.75" of rain in 60 minutes.

A LOOK AHEAD: High-pressure will start to build over the region leading to seasonable temperatures and drier conditions this weekend, although a disturbance to the north will move in over northeastern Colorado during the late afternoon/early evening resulting in a chance for rain/isolated thunderstorms Saturday afternoon/evening. Dry, stable air moves in Sunday with a very low chance of an isolated thunderstorm Sunday evening, mainly in the foothills.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 100 PM TO 800 PM
Trace (70%) to 0.1" (20%) to 0.3" (10%) NONE
Arapahoe 100 PM TO 800 PM
Trace (70%) to 0.1" (20%) to 0.3" (10%) NONE
Boulder 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
Broomfield 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
Denver 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
Douglas 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
Jefferson 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
Foothills above 6500ft      
Boulder 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
Douglas 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
Jefferson 100 PM TO 800 PM
Trace (90%) to 0.1" (40%) to 0.3" (20%) NONE
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.