Time: 143 AM Wed May 10, 2023 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S WILL BE ALLOWED TO EXPIRE AT 2:00 AM/ACTIVE WEATHER DAY AHEAD A second round of strong to severe thunderstorms developed late in the evening impacting NW portions of the District into the overnight period. These storms produced moderate to heavy rain, large hail and numerous lightning strikes. These storms are now located over Weld County to the N of the District and will leave a more stable air mass in their wake allowing Message 1’s to expire at 2:00 AM. Low level moisture continues to advect into the District from the east and may result in rain showers and possibly a weak thunderstorms re-developing into Wednesday morning but the threat for heavy rainfall has passed for the time being. The low level moisture continuing to stream into eastern Colorado and an upper level disturbance moving overhead will set the stage for an active weather day Wednesday. Storms that develop on Wednesday will be capable of producing heavy rainfall and may become severe with gusty winds, large hail and possibly even tornadoes during the afternoon and evening. Another Message Day looks to be on tap to account for the heavy rainfall threat. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak to briefly moderate thunderstorms will produce TR-0.3" of rain in 10-30 minutes. WORST CASE SCENARIO: Moderate to strong thunderstorms are able to re-develop and will have the potential to produce rainfall rates of 0.3-0.8" in 10-30 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME the City of Aurora 1 Current TO 200 AM Current TO 200 AM Arapahoe County 1 Current TO 200 AM Current TO 200 AM DIA 1 Current TO 200 AM Current TO 200 AM Denver County 1 Current TO 200 AM Current TO 200 AM Douglas County 1 Current TO 200 AM Current TO 200 AM Adams County 1 Current TO 200 AM Current TO 200 AM Broomfield County 1 Current TO 200 AM Current TO 200 AM Arvada 1 Current TO 200 AM Current TO 200 AM Jefferson County 1 Current TO 200 AM Current TO 200 AM Boulder County 1 Current TO 200 AM Current TO 200 AM Lakewood 1 Current TO 200 AM Current TO 200 AM Wheat Ridge 1 Current TO 200 AM Current TO 200 AM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Arapahoe Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Boulder Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Broomfield Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Denver Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Douglas Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Jefferson Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Foothills above 6500ft       Boulder Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Douglas Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE Jefferson Current TO 1000 AM WED Trace (75%) to 0.1" (40%) to 0.3" (10%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]