February 20 2019

So far the snow reached or exceeded expectations in most areas. Now we are on to phase 2 which is all about the ice. The storm is far from done. So don’t be tricked by the lull. This is the part I had been trying to bring to your attention. As I wrote last night and this morning, the storm generated more cold air as we waited for the snow to saturate the dry air. Now we have a deeper column of cold air that will be harder to move.

The net result is that warm air will reach the clouds, but cold air will hold longer here on the ground. As a result, we will have an extended period of sleet and freezing rain with up to 1/4 inch of ice. This on top of an average of 4 to 6 inches of snow is not good!

Winter Storm Warning

Extended to 10 PM in central Maryland the normally colder areas west of I-95. Extended to 1 AM Frederick County MD and west.
Winter Weather Advisory along I-95 including Baltimore and Annapolis and Washington to 7 PM, VA south of Washington until 10 PM

Temperatures at 2 PM

Anything falling is still freezing. After 4 PM, when the sun angle gets lower, there will be more ice developing.

Many areas are still below 30ºF in the extended Winter Storm Warning Zone.
It is between 30ºF and 32ºF along I-95 through Baltimore and Washington.

Baltimore Weather Conditions at BWI 2 PM

Temperature = 30ºF
Dew Point = 28ºF
Relative Humidity = 92%
Wind: E at 10 mph

Doppler Radar at 2 PM

Storm Simulation

There is more freezing rain than sleet as of 2 PM. This model has overdone the sleet. Think of most of that as freezing rain.
We are better off relying on nowcasting that the models at this point. This NAM 3 Km Model did not match up with the lull this afternoon. But, I do trust the lull will fill in.
I am showing this more for where the ice line will set up. This matches the extended warning area.

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How Much Ice?

Between 0.10″ and 0.25″ are possible. This is on top of the heavy wet snow in place

Temperatures… Three things to consider:

Cold air is stubborn and may not warm as soon as this model shows.
Even if there is a thaw, it will drop below freezing in these spots by morning.
Ice does not melt as soon as we warm above freezing. It can last for hours, even then fall off of trees, power lines, etc.

There will be leftover impact Thursday morning in the zones that get the most ice (warning area)

Temperatures Tonight

Temperatures Tomorrow

How Did My Snow Forecast Hold Up?

Zone A:

5″ to 8″ of snow. The white circled region can get up to 12″.
The highest snow may be where it begins earlier allowing for more stickage before late morning.
This Zone will have the most snow and heaviest icing Wednesday night

Zone B: