February 14- 17th 1958
This storm developed over the southern Rockies then tracked along the Gulf Coast states before ejecting northeast up the eastern seaboard. Precipitation started on the night of February 15th and persisted through the 16th. Two surface anticyclones kept the atmosphere cold enough for snow. One high pressure slipped off the mid Atlantic coast the night of the 14th, while the next brought a reinforced shot of cold air as it moved across southern Ontario into New England February 16th and 17th. The track of the low just inland along the eastern United States is a favorable track for heavy snow in the West Virginia Mountains, especially if a strong upper level system crosses. Highest snowfall totals were over a foot in the northern and central mountains with greater than six inches across the southern mountains. Of course, lower layers of the atmosphere need to be below freezing, but that was not an issue since surface temperatures resided in the 20s.
The upper level pattern initially consisted of an intense cyclone exiting New England, with another low progressing across the southern plains of Canada. A ridge was present in the western United States and a trough positioned in the central part of the country. The aforementioned low in south central Canada strengthened as it interacted with lower heights in the central U.S becoming closed off when it reached lower Michigan on the 16th. Strong upper level winds and cyclonic vorticity advection downwind of the trough axis strengthened the surface low as it moved east across Georgia. The surface low continued an eastward movement into the Atlantic Ocean and further intensified. The upper low deepened to 504dm across eastern Pennsylvania at 00Z on the 17th.
The 850mb analysis illustrated a deep trough over the central United States with a closed low across Louisiana at 12Z on the 15th of February. The 850mb low traversed the Gulf Coast states and then intensified as it moved north across eastern sections of North Carolina and Virginia. Temperatures across West Virginia stayed below 0C at 850mb for the entire event. With the cyclone deepening, strong cyclonic flow cooled temperatures between -10C to -15C. Two criteria forecasters key on for moderate to heavy snow prediction are areas where forcing lies between the -2C to -8C isotherm at 850mb.
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