Time: 940 AM Thu May 19, 2022 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARM, DRY AND WINDY AHEAD OF A "BRANCH BREAKING" SNOW STORM - Conditions will be warm, dry and windy today ahead of a potent late season spring storm system that will move into the District after midnight tonight into Friday morning. Temperatures this afternoon will warm into the upper 80s to around 90 over the plains. Winds will be increasing from the W into the 10-25mph range with gusts to 35-40mph or more possible. Conditions will remain dry through the day and much of the overnight period. - This evening a cold front will move through and turn winds to the N with rapidly cooling temperatures. The main storm system will begin to move southward overnight with snow developing in the northern mountains after midnight and rain/mix/snow showers starting to fill in from N to S over the plains by around daybreak Friday. Rain, mix and snow pending elevation will then fill in through Friday morning. By noon Friday scattered to widespread rain/mix/snow showers are expected to have filled in over the entire District. - A secondary front will move through early Friday afternoon and will change any mix/rain over to snow along the I-25 corridor. Precipitation is then expected to favor snow for the duration of the event. Snow will intensify Friday afternoon with periods of moderate and heavy snow overnight into Saturday morning. Snowfall rates of 1-3"/hr are likely at times overnight Friday into Saturday morning over the foothills. By noon Saturday the majority of the precipitation from this system will have occurred and conditions will begin to dry out into Saturday afternoon. STORM RAINFALL POTENTIAL AND DURATION: No precipitation expected today and the majority of tonight. Rain and snow pending elevation will fill in Friday morning with precipitation rates (rain/melted snow) of a 0.1-0.4" in 30-60 minutes. A LOOK AHEAD: Total precipitation from Friday morning through midday Saturday in the form of rain and melted snow is expected to range from 1.0-2.0" over the District. Snowfall amounts will be highly variable and favor locations above 6,000ft but preliminary estimates look to be in the 4-8" range between 5,000-6,000ft and 6-12" between 6,000-7,000ft and 10-24" or more above 7,000' in the foothills of Boulder and Jefferson Counties. The heavy, "wet" late season snow has all the tell tale signs of being a branch breaking event for the Front Range. MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]