9 AM Update - 1″ Snow, ETA 6-9 PM, Bitter Cold Mon/Tue

Posted on Sunday, January 5, 2014 @ 6:23 am by David

9:00 AM Update

We have new forecast graphics.

Looks like a pretty nice day! Keep reading.

Snow ETA is 6 PM to 9 PM, but could be as low as 5 PM. Rain should begin before then (around 4 PM or so).

Amounts around 1″ to 2″, with 3″ in a few spots:

Gusty winds will make travel especially difficult:

Very cold temps tomorrow:

That’s the official forecast. Stick with it.

Below are model outputs for tonight’s snow event. These model have their own biases and are not forecasts. The below model snow totals are under what is being forecast, because we don’t think the models are handling the precip:snow ratios well.

5:25 AM Update

At 4:50 AM, our NWS created the following timeline. The headline reads:

The afternoon will be mild and quite comfortable. Remember,

After the arctic front moves through . . . the temperatures fall so quickly to the freezing mark that some meteorologists have come to refer to it as a Flash Freeze. Here’s how (times subject to change, of course):

2 PM Sunday

Temps 50, with a gusty wind from the south. Pretty nice day, but it’s a trap!

5:30 PM Sunday

Raining. Temps in the 40s.

6:00 PM Sunday

Cold front arrives, brining rapidly changing weather conditions: the Flash Freeze.

6:30 PM Sunday

Temps continue to plummet into the mid to low 30s. Rain will likely change to a moderate/heavy snow, which will be coming down so fast, roads will turn white. Driving will start to become difficult.

7:00 PM Sunday

Temps will be at freezing, falling into the 20s. The thin blanket of snow which was melting at 6;30 PM will start to freeze. Driving will become increasingly hazardous. Untreated bridges and overpasses will be especially vulnerable to patchy icy.

7:30 PM Sunday

Temp forecast to be 29, with moderate to occasionally heavy snow still falling. Snow accumulation around 1″. Winds will no longer blow from the south; they’ll turn around from the NW, blowing at 20 mph. Some winds may gust up to 35 mph, which prompted this morning’s Wind Advisory. Wind chills (“feels like”) temperature will hit 15. The first falling snow, which melted only hours earlier, will continue to freeze, producing patches of ice just underneath the snow. Driving will become increasingly difficult and dangerous.

8:30 PM Sunday

Snow begins to taper off, having piled up 1.5″ to 2″. Temps will be in the middle 20s. The snow won’t be going anywhere. Although travel is discouraged everywhere, untreated roads in outlying areas will be especially slippery and hazardous.

8:30 PM to Midnight

Periods of light snow may continue, adding another 0.25″ of snow. Total on the ground: 2″. The temps will drop to 18, with wind chills in the single digits. Many roads will be slick and hazardous.

Monday

Roads are expected to remain snow covered and slippery through Monday as temps fall into the single digits. A few sun rays may peek through the clouds, but that would not be enough to improve road conditions.

NWS concludes: