Snow forecast for D.C. area was a bust. Here's why.

[elleng]

Sometimes, despite our best efforts, it’s just not possible to get it right

'Weather forecasting has come a long way since the 1970s and is among the greatest science success stories of our time. Forecasts are generally quite accurate, even as far out as five to seven days into the future, and have improved enormously since the 1970s. They save countless lives, and their economic value is estimated to be over $30 billion annually (that estimate is from 2009; the value has probably grown considerably since).

But they’re not perfect, and that’s especially true when it comes to snow. Forecasters, like ourselves, obsess over every detail in snow forecasts and still sometimes struggle to get it right. That was clearly the case with Friday night’s forecast. We’re not wrong for lack of trying; the tools we have just aren’t quite good enough yet. Ask forecasters in Boston how they feel about predicting 7 to 13 inches of snow last Monday when only 0.1 inches was ultimately measured. There was sound logic and effort for that forecast, but the storm subtly shifted.

A similar dynamic played out here Friday night, in a less dramatic way.'>>>

https://www.washingtonpost.com/weather/2024/02/17/dc-snow-forecast-bust/?

Our Capital Weather Gang forecast called for about 1 to 5 inches of snow across the Washington region from south to north. Just trace amounts to a few inches fell. The forecast wasn’t wrong everywhere, and it’s not the worst miss we’ve ever had, but it is among the more notable ones in the last few years.

Here how much snow fell in some select locations:

Damascus, Westminster and Elkridge: 3.0 inches
Gaithersburg: 2.8 inches
Lovettsville: 2.5 inches
BWI Marshall Airport: 2.2 inches
Rockville and Laurel: 1.8 inches
Crofton: 1.5 inches
Silver Spring: 1.4 inches
Herndon: 1.2 inches
Dulles Airport: 1.1 inches
Fairfax: 1.0 inches
Northeast Washington: 0.8 inches
Springfield: 0.5 inches
Reagan National Airport: 0.1 inches

So why did we get it wrong? In short, the models we used as tools to make the forecast simulated too much precipitation and the heaviest amounts shifted to the north. On Friday morning, when we analyzed about a half-dozen different models, they all supported the forecast we made.

But trouble started to appear in the afternoon. Ironically, about 15 minutes before the National Weather Service issued a winter storm warning for our western counties, the European computer model — which has the highest skill score of all models — suggested no location in the region would see warning-criteria snowfall, which is 5 inches or more. Its forecast suggested that if every flake stuck, amounts would range from about 1 to 4 inches from south to north.

We were reluctant to scale back our forecast based on the European model by itself. Even though it’s the most accurate model on average, it’s not the best-performing in every single storm. And its snow forecast was only slightly lower than other models. But it presaged a steep decline in amounts in the other models during the afternoon and evening.

A big warning sign was that the high-resolution NAM model — which is among the more reliable in the short term — cut its predicted snowfall by 50 percent between its simulations released Friday morning and Friday evening.'.>>

https://www.washingtonpost.com/weather/2024/02/17/dc-snow-forecast-bust/?fbclid=IwAR1R-uo7VUZCCo2GXdWRgH3s8xYdD-LS0ceUHv2EewsIK0eooyvZ7pe5joE

[bucolic_frolic]

1. You lucked out.

Here in SE PA we had a forecaast for 2-4 inches. What we got was 12-14 !! It was the lightest snow ever, it could be whisked away with the flick of a shovel, but still. they really missed it.

[elleng]

2. Got NUTTIN here in southern MD!

[IronLionZion]

3. I love light snow and miss it from when I grew up in Western PA

DC area gets wet sticky snow which is the worst for driving

[unweird]

4. Forecast here was 2-4"

And neighborly consensus was a good 6” here on the Pittsburgh Northside.