Good evening from SCW,
If the times we live in aren’t strange enough, Mother Nature decided to throw us a curveball and bring a (hopefully) final shot of winter to parts of the state tomorrow evening. With a strong trough dragging down cold air from the north, along with some forcing and atmospheric lift, the table is set for a quick thump of heavy, wet snow across portions of the state. That said, any snow at this point in the calendar is marginal, and this setup especially so. Let’s take a look.
The key variables here are how far north the system pushes and the strength of the precipitation it brings with it. The further north the system, the more warm air gets pulled into our area, and the less snow we see. However, that can be countered to some extent by strong precipitation rates; most of the column is cold enough for snow, so if we get heavy snow just off the surface, dynamic cooling will take over and cool the bottom of the column enough for snow to the surface. Elevation will be just as if not more important than latitude in determining who sees significant snow.
Here’s a look at the simulated radars from the 3km NAM and GFS for 2 AM Saturday morning. These don’t quite tell the whole story here given that the situation is so marginal, and I’d probably expect a solution a little colder than depicted here if one were to verify perfectly. However, they do a good job at illustrating how relatively small ticks in the guidance can lead to a significant difference in outcomes. The GFS is the warm outlier here, the NAM is fairly close to the consensus, while the Euro (not shown) is the coldest of the guidance.
If the times we live in aren’t strange enough, Mother Nature decided to throw us a curveball and bring a (hopefully) final shot of winter to parts of the state tomorrow evening. With a strong trough dragging down cold air from the north, along with some forcing and atmospheric lift, the table is set for a quick thump of heavy, wet snow across portions of the state. That said, any snow at this point in the calendar is marginal, and this setup especially so. Let’s take a look.
The key variables here are how far north the system pushes and the strength of the precipitation it brings with it. The further north the system, the more warm air gets pulled into our area, and the less snow we see. However, that can be countered to some extent by strong precipitation rates; most of the column is cold enough for snow, so if we get heavy snow just off the surface, dynamic cooling will take over and cool the bottom of the column enough for snow to the surface. Elevation will be just as if not more important than latitude in determining who sees significant snow.
Here’s a look at the simulated radars from the 3km NAM and GFS for 2 AM Saturday morning. These don’t quite tell the whole story here given that the situation is so marginal, and I’d probably expect a solution a little colder than depicted here if one were to verify perfectly. However, they do a good job at illustrating how relatively small ticks in the guidance can lead to a significant difference in outcomes. The GFS is the warm outlier here, the NAM is fairly close to the consensus, while the Euro (not shown) is the coldest of the guidance.
Total QPF on the guidance is somewhere between a half and two thirds of an inch for most of the state. If northern elevated areas are able to hold onto all snow, there’s a chance for warning criteria amounts (6”+), however, I think advisory criteria (3-6”) is far more realistic for those areas. For the rest of the state, I’m not confident in anything more than a wet inch or two for northern areas (a lot of “white rain”, i.e. snow that fails to accumulate, is a real possibility), and I think most southern areas will be plain rain, with perhaps a slushy coating of snow mixed in. That said, it would only take a small shift colder to make this a more meaningful event for many; the models being one degree too warm here would bring several inches of snow to most areas away from the shoreline (which I think is cooked regardless here). The trend has been to go ever so slightly warmer on the last couple of runs, hence why I’m a bit less bullish on that small shift colder happening, but there is still a whole day before game time and it’s not out of the realm of possibility that we see shift colder.
Unfortunately I don’t have the map software on this computer, so I can’t visualize it, but I’m going with 3-6” of snow in the hills, 1-3” for northern areas (roughly the northern four counties, though this will be somewhat elevation dependent), and nothing to a slushy inch elsewhere. Should we see a last-second tick colder, I’ll be comfortable taking these numbers up a bit, and I do think there’s the potential for that to occur, but confidence isn’t high enough yet to go for higher totals.
As far as timing goes, expect precipitation to move in around sunset or just after in western areas and quickly spread across the state. I think most precip will be gone by mid-morning (earlier south and west), but a few showers could linger into Saturday afternoon.
I think the main impact will be slick roads in elevated areas; if you’re planning on essential travel Friday evening and roads are bad in your area, please take it slow and think about if you really need to go out or if it can wait until Saturday. Our first responders have enough to worry about right now besides dealing with snow related car accidents. Otherwise, there’s a risk of heavy wet snow causing power outages in the elevated interior if totals near warning criteria do verify, that said, I think they will be fairly isolated in scope.
For the rest of your weekend, expect cool and raw conditions for most of Saturday, with temps only staying in the 40s. Sunday is clearly the pick of the weekend, with temps in the 50s to lower 60s and sunny skies, so we should naturally take care of any lingering snow by the end of the weekend.
I’ll be back with an update tomorrow afternoon if it’s needed, otherwise, enjoy the snow, stay safe, and thank you for trusting SCW.
-SA
Unfortunately I don’t have the map software on this computer, so I can’t visualize it, but I’m going with 3-6” of snow in the hills, 1-3” for northern areas (roughly the northern four counties, though this will be somewhat elevation dependent), and nothing to a slushy inch elsewhere. Should we see a last-second tick colder, I’ll be comfortable taking these numbers up a bit, and I do think there’s the potential for that to occur, but confidence isn’t high enough yet to go for higher totals.
As far as timing goes, expect precipitation to move in around sunset or just after in western areas and quickly spread across the state. I think most precip will be gone by mid-morning (earlier south and west), but a few showers could linger into Saturday afternoon.
I think the main impact will be slick roads in elevated areas; if you’re planning on essential travel Friday evening and roads are bad in your area, please take it slow and think about if you really need to go out or if it can wait until Saturday. Our first responders have enough to worry about right now besides dealing with snow related car accidents. Otherwise, there’s a risk of heavy wet snow causing power outages in the elevated interior if totals near warning criteria do verify, that said, I think they will be fairly isolated in scope.
For the rest of your weekend, expect cool and raw conditions for most of Saturday, with temps only staying in the 40s. Sunday is clearly the pick of the weekend, with temps in the 50s to lower 60s and sunny skies, so we should naturally take care of any lingering snow by the end of the weekend.
I’ll be back with an update tomorrow afternoon if it’s needed, otherwise, enjoy the snow, stay safe, and thank you for trusting SCW.
-SA
