The calendar said spring arrived last Thursday, but mother nature showed complete disregard delivering 1-4 inches of snow and record cold this week. Dulles Airport recorded its two coldest days so late in the season Tuesday and Wednesday (highs of just 33) and plunged to a record-shattering 15 degrees Thursday morning.

But, objectively looking at the weather maps, we can fairly safely say – starting today – we’ve turned the corner. Winter is dead.

How do we define the end of winter in our region?

* No identifiable threat of accumulating snow in long-range forecasts that could remain on the ground for 12 hours or more
* No identifiable threat of a cold weather lasting more than 48 hours when we define cold weather as highs in the 40s (or colder) and lows below freezing in Washington, D.C. (as measured at Reagan National Airport).

If you like spring, the forecast for next week – once we get beyond the poorly-timed rainy weekend (Sunday afternoon/evening may be quite raw) – is a thing of a beauty.

Here’s the output from the GFS model (below) – highs in the 60s to low 70s throughout the work week with lows well above freezing:

Take a look at forecast highs across the region next Wednesday afternoon (below). They look pretty inviting:

When we examine simulations of the GFS model 16-days into the future for Reagan National Airport we see highs mostly in the 50s and 60s.  The chart below is complicated (and busy) but just focus on the red line toward the bottom, which represents freezing, and the black line which is the temperature forecast (from the operational GFS model).  Notice how black line indicating the temperature forecast stays above the red line for the entirety of the next 16 days (although there are a couple of outlier simulations from members of the GFS “ensemble” that touch freezing as indicated by the long blue line segments or “whiskers”).

Before we get carried away with spring fever, two caveats:

1) The European model ensemble shows the potential for a brief bout of chilly weather around April 6
2) CWG’s Matt Rogers, who specializes in long-range forecasting, sees a return of colder than normal weather in mid-April with a chance of having a day or two in the 40s for highs and can’t even rule another chance for conversational (non-accumulating) flakes (20 percent chance). “I believe it will be a “slow spring” but you can safely say we’re departing winter now!,” says Rogers.

After the winter we’ve had – including 16 days with measurable snow, the first on December 8 and the last on March 25, I’m sure many of us will take a “slow spring” in a heart beat.

[polldaddy poll=7921781]

(Note: This is the first announcement in what we intend to make an annual tradition of announcing the end of winter in Washington. Hopefully, over time we’ll build a nice dataset)