Flash Flood Prediction Program

Time: 855 AM Tue June 7, 2022 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARM TODAY WITH A CHANCE FOR AFTERNOON/EARLY EVENING RAIN SHOWERS/ISOLATED THUNDERSTORMS - Elevated surface moisture remains in place behind a disturbance that moved through the region yesterday. Dew points are currently in the low 50's across the District and should hold through the morning. This increased moisture, combined with another weak disturbance will keep a low threat for brief heavy rainfall as some storms have the potential to become severe this afternoon, favoring areas west of the I-25 corridor at this time. Severe storms will favor strong winds with gusts over 60mph along with large hail up to 1.5" in diameter. - Thunderstorms will first develop over the higher terrain to the west between 11am and 1pm with the best chance for storm development in the District between noon and 8pm this evening. A few rounds of storms will be possible, although the best chance for heavy rainfall will be with the initial round of storm development this afternoon. Storm motions from W to E at 10-20mph which will keep storms moving along and rainfall brief from a single storm. Training of thunderstorm cells may result in longer periods of rainfall. - After 8pm rain shower and thunderstorm activity is expected to have diminished with a few light rain showers possible through 10pm with a few scattered light rain showers possible between 2am through daybreak tomorrow. Overnight lows will drop into the low 50's along the plains with mid to upper 40's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" in 10-30 minutes. Moderate to briefly strong thunderstorms will have the potential to produce 0.2-0.5" in 10-30 minutes. WORST CASE SCENARIO: Training of moderate to strong thunderstorm cells, or a severe thunderstorm may produce rainfall amounts of up to 1.0" in 45-60 minutes. A LOOK AHEAD: Warmer, drier air begins to move into the region Wednesday, however a slight threat for afternoon and early evening rain/isolated thunderstorms will remain. The chance for moderate to heavy rainfall will diminish Wednesday with gusty winds and an isolated lightning strike or two being the largest threat. Similar conditions Thursday with high-based rain showers/isolated thunderstorms possible, mainly for areas north of I-70. Drier and even warmer conditions as the weekend approaches with near or at 90° both Thursday and Friday. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1200 PM TO 800 PM Trace (80%) to 0.2" (40%) to 0.5" (10%) LOW Arapahoe 1200 PM TO 800 PM Trace (80%) to 0.2" (40%) to 0.5" (10%) LOW Boulder 1200 PM TO 800 PM Trace (80%) to 0.2" (40%) to 0.5" (10%) LOW Broomfield 1200 PM TO 800 PM Trace (80%) to 0.2" (40%) to 0.5" (10%) LOW Denver 1200 PM TO 800 PM Trace (80%) to 0.2" (40%) to 0.5" (10%) LOW Douglas 1200 PM TO 800 PM Trace (80%) to 0.2" (40%) to 0.5" (10%) LOW Jefferson 1200 PM TO 800 PM Trace (80%) to 0.2" (40%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder 1200 PM TO 800 PM Trace (75%) to 0.2" (30%) to 0.5" (10%) LOW Douglas 1200 PM TO 800 PM Trace (75%) to 0.2" (30%) to 0.5" (10%) LOW Jefferson 1200 PM TO 800 PM Trace (75%) to 0.2" (30%) 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]