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Did this snow catch you off guard? Here's what happened

The forecast was spot on for D.C. with timing and amounts. What was surprising was how much stuck to the roads.

We've heard from many of you that this was more snow than expected or worse than expected and everything in between. For days, the WUSA 9 Weather Team has been talking about the threat for snow and a wintry mix heading to our area. Here's how the storm shook out.

What We Forecast vs. What Happened

Around Tuesday we started mentioning that we would see a wintry mix around D.C. with a change over to rain by afternoon. We forecasted a wintry mix and a trace to 2 inches of snow around parts of the D.C. Metro area. The forecast was spot on for D.C. with timing and amounts. What was surprising was how much stuck to the roads. The snow came down heavy enough to overcome the warmer ground temperatures and stick to roads.

We actually ended up adjusting our snow maps during the onset of snow. The storm generated more snow in southern Maryland than expected, where a winter weather advisory was not issued. It was eventually added to the advisory. This meant more snow rather than rain for areas south of D.C. like Mechanicsville and Waldorf.

The Complexity of It All

Whenever you have a nor'easter and a wintry mix in the forecast, that spells a complex weather situation. We are waiting for all of the right ingredients to come together for snow to fall. For example, we need air that is moist and this morning it started off rather dry. Think of it this way, we need a glass full of water for snow or rain to fall and this morning it was only about 1/4 of a cup. We have an idea of when the glass will fill up, but more than likely it's going to happen when the atmosphere gets around to it. It has its own schedule and we get penciled in, just being honest.

Here is our forecast of snowfall from 6 PM Wednesday night.

Here is our snowfall prediction from 6 PM Wednesday evening.

Here are some actual totals on top or our predicted snow bands.

On top of our predicted snowbands are the actual amounts.

Snow reports:

National Airport: 1.4"

Dulles: 3.0"

Damascus: 4.4"

Chevy Chase: 1.8"

Thurmont: 6"

Smithsburg: 6"

Winchester: 5.0"

Leesburg: 4.0"

Harpers Ferry: 7.0"

Hagerstown: 6.5"

Chantilly: 2.1"

Frostburg: 7.5"

Martinsburg: 7.0"

Columbia: 2.0"

In Closing:

A lot of physics, and hundreds of thousands of calculations are going into the weather models (GFS, NAM, GEM, EURO, HRRR), but at the end of the day there will always be a little wiggle room with timing or type of precipitation.

By the way, we liked the European model for this storm. It was one the first models to bring the wintry mix over Metro D.C.

Enjoy the snow. It's going to be a busy winter.

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