Light rain will change to snow later this evening and snow will fall, now and then, through early afternoon Thursday when temperatures warm enough to turn it back to rain. We warm up and dry out by the weekend with nice weather most of next week.
The surface map for Thursday AM (Figure 1) shows a big shield of snowfall over most of Colorado. Light rain should turn to snow about 9-10pm with snow showers continuing until around 1pm Thursday.
Longmont should pick up about 0.25-0.50 inch of water over the next 48 hours (Figure 3). For snowfall, the GFS gives us about 1 inch of snow (Figure 4). The HRRR model (which only runs through 4am Thursday – Figure 5) does not give Longmont measurable snow. The forecasters at wether5280.com are giving us 0-2 inches (Figure 6).
I’m calling for 1/2 to 3 inches on grassy cool surfaces (including elevated bridges and overpasses).
The Longer Range Forecast:
The storm pulls away (to the south and west!) Friday morning (when a bit more snow might fall – but not much to measure). We warm to the 70’sF by the end of the weekend and have nice weather on into next week. We’ll look at afternoon storm chances in a future post.