Time: 938 AM Wed May 18, 2022 Forecaster: Laura Smith ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- HOT WITH HIGH-BASED AFTERNOON/EVE RAIN/ISOLATED THUNDERSTORMS - Today, high pressure continues with temperatures reaching the upper 70's to low 80's, dew points in the upper 30's, under partly cloudy skies. A slight chance for high-based rain showers and isolated thunderstorms expected this afternoon through the early evening. - Isolated showers and thunderstorms will roll off the foothills and Palmer Divide between 12-1pm with the best chance for rain shower activity through 6pm. Precipitation will be light with some lighting and gusty wind possible. Showers are expected to move east-southeast between 5-15mph. - Skies are expected to clear by 9pm tonight. Overnight lows will reach the mid 50's with dew points in the upper 30's. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers/isolated thunderstorms will produce a trace to 0.1" of rainfall in 10-30 minutes. Weak to moderate thunderstorms will have the potential to produce rainfall rates of 0.1-0.3" in 10-30 minutes. WORST CASE SCENARIO: A moderate to strong thunderstorm, or training of thunderstorms with the potential for moderate to brief heavy rainfall of 0.3-0.8" in 30-60 minutes. A LOOK AHEAD: A dramatic shift in the Jetstream will create a wild weather pattern across the Front Range Urban Corridor over the next several days as a cold front and associated storms system move through the area on Friday. Tomorrow will be hot, dry, and gusty with highs reaching the upper 80's to around 90 degrees ahead of a cold front tomorrow night. Scattered rain showers will begin overnight following the frontal passage, becoming widespread by Friday afternoon. High temperatures on Friday will reach the upper 40's to low 50's. Rain is expected to change to snow later afternoon or early evening. Overnight temperatures will fall into the low 30's. Snow will mostly be limited to grassy areas and branches, with very little accumulation on pavement. There is a potential for slushy accumulations if snow rates exceed 1" but is expected to melt quickly. Heavy wet snow may compromise gardens and break greening tree branches. Models place heaviest snowfall across higher elevations of the foothills and Palmer Divide. Snow will continue through Saturday morning, ending by midday. Highs will reach the upper 40's, with clearing skies later day or overnight. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1200 PM TO 700 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Arapahoe 1200 PM TO 700 PM Trace (40%) to 0.1" (15%) to 0.3" (5%) NONE Boulder 1200 PM TO 700 PM Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE Broomfield 1200 PM TO 700 PM Trace (40%) to 0.1" (15%) to 0.3" (5%) NONE Denver 1200 PM TO 700 PM Trace (40%) to 0.1" (15%) to 0.3" (5%) NONE Douglas 1200 PM TO 700 PM Trace (50%) to 0.1" (15%) to 0.3" (5%) NONE Jefferson 1200 PM TO 700 PM Trace (40%) to 0.1" (15%) to 0.3" (5%) NONE Foothills above 6500ft       Boulder 1200 PM TO 700 PM Trace (40%) to 0.1" (15%) to 0.3" (5%) NONE Douglas 1200 PM TO 700 PM Trace (50%) to 0.1" (20%) to 0.3" (10%) NONE Jefferson 1200 PM TO 700 PM Trace (50%) to 0.1" (20%) 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]