My Final Snow Map


Rain and/or Sleet will change over to heavy snow between 6 and 9 AM in DC (earlier across the NW suburbs and later in the SE suburbs).  Road conditions will deteriorate rapidly throughout the day on Thursday.

Snowfall rates will occasionally reach 2″ per hour between the morning and afternoon rush hours.

I think everyone will receive 5 to 6″ inside and around the Capital Beltway with 6 to 10″ in the northern and western suburbs. Even locations in the eastern and southern suburbs (away from the urban heat island of Alexandria, south Arlington and Downtown DC) could pick up 7 or 8″ of snow.


Short Range Models 101: Probability of 6″ of Snowfall Accumulation


SREF Probability of receiving greater than 6″ of Snowfall. Image courtesy, Weatherbell.


In the weather world, you have long-range, medium-range and short-range forecast models.  You also have control runs and ensemble runs.  If you needed surgery for a medical condition, you would probably want a second, third or fourth opinion on your treatment options.  In the  weather forecasting world you want to look at the ensembles as they give you multiple opinions for the same run (with slightly different initialized inputs).  Here are the latest SREF snowfall probabilities at the three main airports for tomorrow’s storm:

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How Much Snow Will Fall in Your Neighborhood?

Latest European Forecast Model; Image courtesy Weatherbell.

Latest European Forecast Model; Image courtesy Weatherbell.

Here’s the model data… now you decide. How much snow are you going to get in your neighborhood? “But Tim, they all say something different”. Welcome to the world of weather forecasting. Add angry commuters stuck in gridlock (as your viewers) on ice packed roadways (as Boston makes fun of you for being snow wimps) … and it gets a little intimidating doesn’t it.

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