Columbia County Surprise Snow : 11/26 – 11/27/21

While many of us saw our first dusting to a half inch of snow on Sunday… anyone who lives in Columbia County (especially eastern Columbia County), or the extreme NE corner of Dutchess County, is probably yawning about Sunday’s dusting. That’s because they received a bit of a surprise snowstorm on the back side of Friday’s rain event.
As the coastal low pressure intensified and lifted into New England, the strong NW flow on the back side of the storm pulled cold air into the region. But the wind direction also was perfectly aligned to enhance the precipitation over the eastern most portion of Columbia and Renssalaer Counties.  If you look at the elevation map of New York, you can see the boxed in area starts with low elevation near the river, with the high elevation near the NY/CT border.
The rise in elevation causes the air to rise as well.  That lift in the air, causes air to cool and condense… which results in enhanced precipitation rates.
Everything comes together in a situation like this, to cause a localized heavy snow event over a rather small geographical area.  The higher elevations saw in excess of ONE FOOT of snow from this difficult to predict event.  Guidance suggested that a coating to 2 inches was likely in eastern Columbia county… but the actual result was dramatically different.  The combination of available moisture, cold NW wind in just the correct direction, resulted in elevation enhanced snowfall.  Part of what makes the Hudson Valley a unique area to experience unique weather events.

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