Time: 819 PM Tue May 9, 2023 Forecaster: Brad Simmons

Internal Message Status
Flash Flood Prediction Program

MESSAGE 1'S CONTINUE VALID
Message 1’s will continue valid for the next few hours but may be cancelled early if conditions remain quiet over the District. Strong thunderstorms developed over parts of Adams and Denver Counties late this afternoon and produced large hail as well as moderate to heavy rainfall.

These strong thunderstorms have moved out of the District but these storms also produced an outflow boundary which has pushed westward into the foothills and may be a trigger to generate additional thunderstorms this evening. If this outflow boundary does not result in new thunderstorm development Message 1’s may be cancelled early as they are currently valid until 2:00 AM Wednesday.
STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.4" of rain in 30-60 minutes. Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.4-0.8" in 10-30 minutes.

WORST CASE SCENARIO: A slow moving strong thunderstorm or training of thunderstorm cells may result in up to 1.5" of rain in 45-60 minutes.

County Message Valid Times Prime Time
Boulder County 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Jefferson County 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Broomfield County 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Douglas County 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Adams County 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Denver County 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
DIA 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Arapahoe County 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
the City of Aurora 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Arvada 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Wheat Ridge 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM
Lakewood 1 Current TO 200 AM WEDNESDAY Current TO 1100 PM

County-specific Quantitative
Precipitation Outlook
Precipitation Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams Current TO 1159 PM TUE
0.1" (50%) to 0.4" (25%) to 0.8" (10%) ISSUED
Arapahoe Current TO 1159 PM TUE
0.1" (40%) to 0.4" (20%) to 0.8" (5%) ISSUED
Boulder Current TO 1159 PM TUE
0.1" (65%) to 0.4" (30%) to 0.8" (15%) ISSUED
Broomfield Current TO 1159 PM TUE
0.1" (60%) to 0.4" (30%) to 0.8" (15%) ISSUED
Denver Current TO 1159 PM TUE
0.1" (50%) to 0.4" (25%) to 0.8" (10%) ISSUED
Douglas Current TO 1159 PM TUE
0.1" (30%) to 0.4" (15%) to 0.8" (5%) ISSUED
Jefferson Current TO 1159 PM TUE
0.1" (50%) to 0.4" (25%) to 0.8" (10%) ISSUED
Foothills above 6500ft      
Boulder Current TO 1159 PM TUE
0.1" (70%) to 0.4" (30%) to 0.8" (15%) ISSUED
Douglas Current TO 1159 PM TUE
0.1" (40%) to 0.4" (20%) to 0.8" (5%) ISSUED
Jefferson Current TO 1159 PM TUE
0.1" (50%) to 0.4" (25%) to 0.8" (10%) ISSUED
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.
https://f2p2.udfcd.org/generator/