The warm temps and rain of earlier this week is in the rearview mirror and a cold and wintry weekend is in store. There are two small snow events on tap in the short range and cold air continues through most of the forecast period before we look to warm up again towards the middle of next week.
Since Tuesday, we’ve been tracking a clipper system that is currently transferring to a weak secondary low off the coastline. While the system is too weak to bring a significant storm to the area, we will still see some snowfall, and with cold temps, the “fluff factor” will be in play, with snow ratios around 15:1 likely. As such, it’ll only take a few hundredths of an inch of liquid to produce a light snowfall for the area, and due to the cold temps, it should stick pretty much instantly.
The global models are fairly weak with this feature, while the mesoscale models have a slightly deeper low pressure and thus a larger precipitation shield. To illustrate, here’s a look at the 18z GFS and the 18z RGEM, both valid for 7 AM tomorrow morning.
For the rest of the state, while we will see several hours of snow overnight, rates will be very light, and the liquid for anything more than a heavy coating to an inch or so will be hard to come by. Some spots, especially in the southern portion of the zone could come closer to 2” if they get into good banding for a short time, and so I have made the upper end of the forecast 2” to account for that possibility, but generally I expect most totals to be in the coating to an inch range.
However, despite the light totals, this event will have an impact due to the timing; snow will be wrapping up just as the commute is in full swing, leading to some potential travel issues tomorrow morning. Shouldn’t be anything too terrible, but leave some extra time and take it easy out there! Some scattered school delays are possible as well.
Otherwise, expect snow to move out of the state by mid-morning, and we should see clearing throughout the day, with highs topping out in the upper 20s to lower 30s.
Hot on the heels of Friday’s system comes a second system, this time a Miller A from our south. This system was modeled as a substantial snowstorm for us in the long range, but for the past several days, has been shown to scoot out to sea after bring a substantial snowstorm to the south as the system isn’t able to turn the corner up the coastline and escapes east. However, on the 12z suite of guidance today, we saw a defined trend on the guidance to strengthen the shortwave as well as amplify the PNA ridge in the pacific, sharpening the eastern trough and allowing the storm to stay closer to the coast as it moves north. The end result was a fairly substantial shift to the west with accumulating snows. As always, there are significant discrepancies in the models, with the NAM family being the most aggressive followed by the GFS and EURO and the GGEM being the furthest east.
Here’s a look at the most recent runs of the NAM, GFS and GGEM, all valid for 7 PM Saturday.
Of course, you’re probably wondering which one I’m going to pick. As much as I’d like the NAM to verify, I think it’s overdone here. While the west trend is clearly legitimate, we would need to see another shift of roughly the magnitude we saw today for other models to match the NAM solution, and at this lead time, that is unlikely. At the same time, I do think the trend has merit, as we have seen this sort of trend at short range before, most notably February 5th of last year. For now, I’ll lean towards the GFS as a middle ground compromise, which would result in a light snowfall in eastern areas with little or nothing further west. However, keep in mind that should the trend west continue, the ceiling on this event would increase rather quickly. We will closely review the overnight guidance in the morning, and, if necessary, will issue a snowmap around 1 PM tomorrow afternoon.
Clear and cold weather is expected for the second half of the weekend and into next week before another system cuts to our west midweek. As of now, it looks like it is modeled as a mostly rain event, but we have seen these cutters trend towards an icier front end several times this winter so far. With the cold airmass in place, it is quite possible that we will see that again with this system, and as such will go for a wintry mix in the forecast. At this lead-time and considering the active short range, will not focus too much on this system and will leave it for the next forecaster. Quiet weather returns to close out the week.
Friday: Snow early, then gradually becoming partly sunny. Highs in the upper 20s to lower 30s. Chance of snow is 80%. See snowmap for detailed accumulation forecast!
Saturday: A chance of snow in the afternoon and evening, otherwise, mostly cloudy, with highs in the mid 20s. Chance of snow is 30% in western areas and 60% in eastern areas.
Sunday: Mostly sunny, with highs in the mid 20s.
Monday: Mostly sunny, with highs in the mid 20s.
Tuesday: Mostly sunny, with highs in the mid to upper 30s.
Wednesday: A chance of rain, sleet, or snow, otherwise, mostly cloudy, with highs in the upper 40s to lower 50s. Chance of precipitation is 50%.
Thursday: Mostly sunny, with highs in the low to mid 40s.
Enjoy the snow, have a great weekend, and thank you for reading SCW!