Ice Tonight

9:30AM Update:
Obviously, some schools canceled today, including Moco due to the ice. Temperatures have risen above freezing across most of the area. Expect melting an improving conditions. The winter Storm warning is set to expire at 10:00 AM so that's all folks. The rest of the day will have temps rise the mid to upper 40s lower 40s and rain with clearing later.

10:20PM Update:
Light freezing rain and rain has overspread the area. Areas to the north and west have the freezing precip, but those close to or inside the beltway have just plain rain as temps are hovering just above freezing. We can expect these temps to drop below freezing eventually. The NWS has raised ice totals slightly along the eastern edge. The radar is rapidly filling in as the primary low approaches from the southwest.

8:45PM Update:
Dewpoints are quite a bit lower than forecasted, meaning evaporative cooling may lower temperatures more than expected, prolonging the cold. This also might indicate that the high is stronger than expected, once again, pushing more cold air in. Precip is approaching from the south.

SPC analysis shows the freezing line across Moco at 8:00PM. The purple line denotes below freezing temperatures and there is a 2 degree difference between the lines. The tan lines are the same except for temperatures above freezing. 

The wet bulb temperature is the temperature that the air could be cooled to by evaporative cooling if the air was completely saturated such as by evaporation of precip. Red is above freezing and blue is below freezing.

8:10 PM Update:
If you think we had it bad with the polar vortex and all this winter, take a look at Slovenia. 2+ inches of freezing rain is no joke. It was estimated that 25% of the population was without power and 40% of its forests damaged.

More pictures here.
7:00 PM Update
Surface are approaching freezing if not already below. The 18z model runs have not come in any different than previous runs so the previous forecast will remain unchanged. Temperatures will continue to drop before rising early in the morning in response to a surge of warm air from the south. Something to note is that there seems to be a weak low pressure system developing off the Carolina coast. The effects, if any, of this new secondary low is yet to be seen.

Main low is working NNE to the west, weak baby low is off the Carolina coast

Original Text:
The winter storm watch has been updated to a warning, calling for .25 inches of freezing rain and up to an inch of sleet. The sleet accumulation will be mostly confined to the far north and west. While the northern half of the county is in for an icy mess, the southern half is less certain. Models show a surface low moving from the gulf north towards us and passing us just to the west. The NAM and CMC also show a secondary low developing off the coast while the old low dissipates. This will keep a northerly component to the winds for a longer period of time, keeping it cold. The GFS, on the other hand, keeps the primary low strong, eroding out the cold air much faster than forecasted. Temperatures should rise above freezing from southeast through northwest mid tomorrow morning as the temperatures rise in response to southerly flow from the approaching low.

The NWS scaled down totals to the south and east, likely in response to warmer temperatures and higher uncertainty in the forecast. We shall watch the temperatures and depending on how far we can drop, adjust the forecast accordingly. If this forecast were to verify, we would likely have no school but due to the uncertainty of the forecast, I think that Moco will delay the decision until as late as possible, forcing us to wake up to check tomorrow at 5:00AM. 

Thanks for reading!

-Alex