After two blizzards in the span of a week I spoke with John Cifelli, a meteorologist and the author of John Cifelli’s WeatherNJ. John and I talked about his motivations for working in meteorology and the current whitewash outside our windows.

K Exchange: First off, can you tell us why you wanted to be a weatherman?
John Cifelli: I love snow; the Blizzard of ‘96 was something I’ll never forget. As a boy, watching Niko, my German Shepherd who stood over 6 feet on her hind legs, having to bound like a deer through 4 foot drifts  was just incredible. I wanted to know why, and I wanted to know when it would happen again! I’m also terribly competitive, and I love a challenge. As I entered college, I realized that meteorology offered me the opportunity to satisfy my passion for weather, and the chance to compete with my peers in challenging forecasting situations.

KX: Do you consider yourself a scientist?
JC: A meteorologist is certainly a scientist. From a forecasting perspective, the goal is to analyze a wealth of data, decide what is relevant, what is flawed, and present the most likely solution. It is much more subjective than other sciences in the sense that much of what a weather forecaster looks at is open to interpretation.

KX: What causes a big storm like the one we have now? Is it similar to any other storm?
JC: A snowstorm, like all weather systems, is a result of unequal heating on Earth. The equator receives the bulk of the sun’s energy, while the poles receive the least. A storm represents a heat flux in an attempt to balance this unequal distribution of energy.

KX: What’s involved in actually predicting storms like this? We heard anywhere from 6-10 to 10-18 inches for this storm, how do you arrive at these numbers?
JC: Different meteorologists can look at all the information before them in different ways. There are many different computer models- the NAM, GGEM, ECMWF, GFS just to name a few. They are all governed by the “primitive equations” of the atmosphere, which are physical algorithms for the basic properties of everything going on above you- temperature, pressure, humidity, etc. But they have different spatial scales, resolutions, boundary conditions, and data input.

To make matters more confusing, they run all of these models up to 4 times a day. Then they run models that use the solutions of these primary models as input to give more ideas of what could happen. Then they have ensembles of some of these models, where they tweak one of the equations to show what could happen in a slightly different scenario. The GFS, for example, has over 20 ensembles. All of these projections can vary, sometimes to an extreme extent given a certain timescale. The amount of data a meteorologist has at their disposal is overwhelming, and deciding what is or isn’t useful isn’t always easy.

Specifically for a snowstorm, a forecaster has to consider temperature, wind speed/direction, humidity, and then consider those variables at all levels of the atmosphere, over areas with very unique microclimates (consider the differences between Sparta and Atlantic City in New Jersey) and over considerable periods of time. Then, even if the near term forecast was essentially perfect, I haven’t even touched on chaos theory- what happens at hour 36 and 48 if the forecast was just a little off at 12 or 24.

KX: How is it that, as with Saturday’s storm, Southern NJ can be hit by over a foot of snow, while areas 40 miles north get almost nothing?
JC: Last weekends storm ran into a region of strong confluence in New England that reached down into northern NJ. Confluence is the convergence of streamlines- paths of wind- aloft. In order for any precipitation to occur, there needs to be a lift mechanism to transport air from the surface to higher altitudes where it cools, condenses, and precipitates. Air cannot be lifted into a region of confluence very easily. You can visualize the amassing of air aloft where the streamlines converge. How are you going to lift more air into an area that already has too much? As a result, confluence leads to sinking air at the surface, the opposite of what you need for rain or snow. South Jersey didn’t have this sinking air regime, so the gradient of haves to have-nots with regards to snow was pretty tight.

KX: Is it unusual for an area to be hit by two storms of this size in such a short period of time?
JC: To have back to back blizzards isn’t just unusual, it’s historic. These storms, combined with the  snowstorm on December 19th put this season in the highest echelon of mid-Atlantic winters. This winter is already a 1 in 50 years type event for people in the Baltimore-Philadelphia corridor. Tack on a late season snowfall or two, and this could end up being a once in a lifetime winter. Truly, history in the making.

John Cifelli has produced forecasts specifically for New Jersey and surrounding metro areas since 2004. You can join his weather newsletter John Cifelli’s WeatherNJ by contacting him at johncifelli@gmail.com.