Flash Flood Prediction Program

Time: 927 AM Wed May 29, 2024 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Warmer today with a chance for afternoon and evening showers/thunderstorms Upper-level winds shift westerly today for the District which will effectively increase high temperatures today into the low to mid 80s. Late evening showers and thunderstorms last night has increased surface moisture today and will have the potential for a more active afternoon and evening across the I-25 corridor. Storms will initiate along the higher terrain in the early afternoon with the best chance for storms withing the District between 2-8pm today. Storm motions will be from west to east between 10-20mph which will help limit point rainfall amounts, however, some erratic storm motions will be possible due to outflow boundaries. These erratic storms will have the highest potential for heavy rainfall with the largest threat today being a quick 0.5” in 10-20min rather than any long-lasting rainfall. A slight chance for a few lingering showers into the later evening, although the threat of heavy rainfall should diminish after sunset. Overnight will likely clear out as temperatures dip into the low to mid 50s by daybreak tomorrow. STORM RAINFALL POTENTIAL AND DURATION: Typical showers and isolated thunderstorms will produce T-0.25” total in 10-30 minutes. A moderate shower/thunderstorms will produce 0.25”-0.50” total in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorms, or a stationary storm will have the potential to produce up to 1.00” total in 10-30 minutes. A LOOK AHEAD: A trough of low-pressure will meander into the Colorado region tomorrow, likely increasing upper-level support, which in turn will increase chances for widespread showers with moderate to heavy rainfall possible at times. Tomorrow’s high temperatures will reach around 80 degrees in the afternoon with clouds increasing as storms likely indicate along the higher terrain by midday. Tomorrow will likely result in a MODERATE chance for Message 1s to be issued. Slightly drier overall Friday will likely decrease the heavy rainfall threat, however, an abundance of left over moisture at the surface from the previous day will likely result in at least a LOW chance for Messages to be issued. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 900 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Arapahoe 200 PM TO 900 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Boulder 200 PM TO 900 PM Trace (60%) to 0.25" (30%) to 0.5" (10%) LOW Broomfield 200 PM TO 900 PM Trace (60%) to 0.25" (30%) to 0.5" (10%) LOW Denver 200 PM TO 900 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Douglas 200 PM TO 900 PM Trace (60%) to 0.25" (30%) to 0.5" (10%) LOW Jefferson 200 PM TO 900 PM Trace (60%) to 0.25" (30%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder 200 PM TO 900 PM Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Douglas 200 PM TO 900 PM Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW Jefferson 200 PM TO 900 PM Trace (50%) to 0.25" (25%) to 0.5" (10%) LOW MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]