A powerful disturbance (we call them jet streaks) now a few hundred miles westof Washington and Oregon will bring periods of heavy snow to the northernRockies Thursday night and Friday. Elevations above 7,000 feet can expect afoot or more of snow and travel will be difficult over the passes.Beyond that, all the energy with this system will cascade toward the SoutheastSaturday and force the development of a deep upper-air trough over the lowerMississippi Valley. In most cases, the words "upper-air trough" and "storm" canbe used interchangeably. One is just a reflection of the other. After all, theatmosphere is three-dimensional and there are no gaps between surface andupper-air systems.
In any case, the entire trough, storm or whatever you want to call it, willtrack toward the Northeast later Saturday and Sunday and grow stronger as itgoes. The heavy snow pattern produced by the storm will begin somewhere inMissouri or Illinois then expand toward the Northeast impacting Indiana, lowerMichigan, Ohio, western New York, western Pennsylvania and eventually Canada.
This will be a pretty bad snowstorm for the region with major travel delays andnumerous cancellations.
Story by AccuWeather.com Senior Meteorologist John Kocet.
