Forecast Blogs

Not Again! (Tonight…and Monday?)

Current Radar 

Tonight – A Little More Snow

As you can see from the above radar, a long, narrow ribbon of snow continues to drive down I-24.

Dry air aloft, personified by the Dry Air Monster, has been eating (evaporating) some of the precip, but not all of it. If you have a window, you can verify. The DAM hasn’t been hungry.

Temps are only going to drop further tonight, settling into the low 20°s. The only issue is whether the snow will stay over us.

Initially, the snow will gather on grassy areas, decks, windshields, etc. Sunlight from this afternoon warmed road temps past freezing, but only barely past freezing. Areas which will see the heavier, training snow should reinforce the black ice concern, and maybe even whiten up secondary and tertiary roads.

The big question is: how long we can expect this to continue? The HRRR model, below, is not impressed.

This model significantly decreases the intensity and coverage of the snow through the early evening hours, disappearing it by midnight. I’m not entirely comfortable relying on the HRRR for this event; I feel like it has been under-doing snowfall totals with this week’s clipper, but I don’t really want to discount it, either.

The narrow snow ribbon is moving like a conveyor belt SE, along the “route” of I-24. See the black arrows below.

Yet, the system itself is also sliding east. See the yellow arrows. As the snow band moves east later tonight, snow will start switching off from west to east. It’s difficult to say exactly when it will roll off us. Winds aloft are WNW enough to nudge it that way, but it’s hard to really say how long it will take. We’ll have to track this feature very closely on Twitter. I think it’ll be here for at least a few hours.

Officially, NWS expects another half-inch from this, but we’ll have to watch it closely. There is potential we might see more than that in places, but that’s currently not part of the forecast.

Anything that falls tonight is going to freeze. Black ice will remain a problem, especially on bridges, overpasses, and areas at elevation, and especially for those areas getting the heavier snow bands. Main roads will do better than secondary roads.

Temps Above Freezing Tomorrow

We think will be above freezing just before noon. We’ll be heading to a high of 40°, and we might be able to mix in a little sun to aid in snowmelt. Temps dive back below freezing Thursday night into Friday morning; however, Friday our high will be 44°, and we should be able to rid ourselves of the snow/ice problems.

Arctic Air This Weekend

More Snow Monday?

Models vary rather dramatically.

The GFS model brings in snow Sunday night through early Monday morning, around 1 to 2 inches of accumulation.

The European model presents a much different meteorological scenario than the GFS. It sends in a weather system from Arkansas, bringing temperatures just above freezing — and therefore rain — during the day Monday. Then, Monday night, we finally get cold enough to change some of that rain over to snow.

Forecast confidence regarding the timing, and therefore the precipitation type, is very low. However, both models indicate some snow solution, albeit at different times. This failure of model consensus creates low forecast confidence. We will update this again tomorrow as the new model data arrives.

This website supplements @NashSevereWx on Twitter, which you can find here.

Categories: Forecast Blogs