Appreciating the Complexity Winter-time Coastal Storm Forecasting (credit: NOAA GOES-16 Satellite)
DISCUSSION: During the course of a given Winter season, there is always a decent chance for snowstorms to occur depending on how different oceanic and atmospheric parameters do or do not come together. When it comes to predicting how a given Nor'easter may or may not unfold during a given period of time, it is important to consider a few specific factors. First off, one of the first aspects to consider when anticipating the likelihood of a given Nor'easter developing is whether there happens to be a sufficient horizontal temperature gradient between coastal as well as semi-inland sections of the Northeast and the far western Atlantic Ocean. This horizontal temperature gradient is what provides the critical baroclinic zone (i.e., a horizontal zone of rapid temperature change at the surface which effectively creates a horizontally-oriented Winter-time atmospheric instability. It is typically acknowledged as a native Winter-time atmospheric instability based on the fact that you only ever find a sufficiently strong horizontal temperature gradient during the Winter since this is when the ocean is still relative warm (due to a greater net heat capacity) and the land is much colder due to periodic bursts of colder (sometimes Arctic) air which descend out of southern and southeastern Canada.
The other major factor which is directly tied to anticipating the likelihood of there being sufficient upper-level support which has to do with the strength of upstream atmospheric dynamics (namely the amplitude of a given trough). A trough is effectively a "bowl" of much colder air in the upper levels of the atmosphere which will dive down into the central and/or eastern United States during more favorable Nor'easter set-up scenarios. As a result, depending on the given amplitude of the incoming trough, this often dictates the amount of corresponding energy associated with a upper-level jet features which act as upper-level support for a surface/mid-level extra-tropical cyclone.
When all of these things come together, you can quickly find a blossoming Winter-time coastal storm develop and consequently observe (via various high-resolution satellite imagers such as NOAA's GOES-16 satellite imager) very complex convection pivoting around the eastern, northern, and western periphery of the developing surface low. Such an example is reflected by the animated visible satellite imagery above which captures intense convection coming ashore into coastal sections of New Jersey and New York earlier in the day on Wednesday (March 7th, 2018).
To learn more about other high-impact weather events occurring across the Atlantic Ocean and Caribbean Sea, be sure to click the following link: https://www.globalweatherclimatecenter.com/atlantic-ocean-and-caribbean-sea!
© 2018 Meteorologist Jordan Rabinowitz
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