9:50 AM | *The amazing blizzard of March 1958*

Discussion

Overview

March is known to feature some crazy and surprising weather and the 1958 blizzard that occurred in the Mid-Atlantic region between March 18th and 23rd was indeed rather unexpected. In general, forecasts on the morning of March 18th had no mention of snow. This was in an era before computer forecast models were being utilized by weather forecasters and even before satellite imagery existed which could aid in the forecast. By afternoon on that particular day, the light rain had changed into huge, wet snowflakes and - for the next few days - history was being made.

Details

This was a relatively warm storm and it was quite a struggle for the precipitation to fall in the form of snow. However, as low pressure intensified off of the Mid-Atlantic coastline, heavy, wet snow began to pile up. Under the weight of the heavy, wet snow, it didn’t take long for trees to start snapping in the Mid-Atlantic region and power outages spread as electric power lines started coming down. In addition, many houses suffered severe damage to roofs, porches and sheds as incredible amounts of heavy wet snow piled up.

[Surface map on March 20th, 1958]

The most striking characteristic of this storm was its slow-movement resulting in substantial accumulations over a several day period. Also, as is often the case in March, the snow accumulations during this event became extremely dependent upon elevation whereby significant differences occurred at differing elevations. A couple degrees of difference on the thermometer between lower and higher elevation locations made huge differences in snowfall totals. One of the most amazing results occurred in Morgantown, PA at an elevation of 750 feet in which an astonishing 50 inches of snow accumulated during the March blizzard - still the highest ever for a single snowstorm in southeastern PA. In fact, snow piled up on ridge tops all the way from southeastern to northeastern PA with an incredible five feet of snow (60 inches) covering the ground by March 23rd in the small Poconos village of Gouldsboro – still the greatest amount ever in the state of Pennsylvania for a single snowstorm. Other notable snowfall measurements included 35 inches in Stroudsburg, PA, 33 inches in Mount Airy, MD, and 20 inches in Allentown, PA.

[Snowfall totals for the period of March 18-21, 1958; courtesy NOAA]

In lower elevation location such as in the city of Philadelphia “only” 11.4 inches fell as slightly milder temperatures and the lack of orographic enhancement (i.e., precipitation being “squeezed out” of the atmosphere due to rising air on windward-facing mountains). Other urban centers were hit as well with this late season snowstorm including Washington, DC at 4.8 inches, Central Park, NY at 11.7 inches and Boston, MA at 6.7 inches. This storm was not the only snowstorm in that great winter of 1957-1958 as just four weeks earlier another major event occurred in much of the same region.

Similarities between the winter of 1957-1958 and 2014-2015

There are many similarities in global patterns between the winters of 1957-1958 and this winter with perhaps the most important being relative to the sea surface temperature (SST) anomaly pattern in the all-important Pacific Basin. The comparison map below shows the SST anomalies in February 1958 (left) and February 2015 (right) with many striking similarities. Specifically, very warm water existed in both cases off the west coast of Canada and the US. Also, colder-than-normal water existed in both years across the north-central Pacific Ocean. Finally, in both cases, the central part of the tropical Pacific Ocean featured warmer-than-normal waters (i.e., a "centrally-based" El Nino).

[Sea surface temperature anomalies in the Pacific Basin during February 1958 (left) and February 2015 (right)]

All indications suggest that a winter-like pattern will resume here in the Northeast US following our current “spring break” and this transition back to colder-than-normal could begin as early as next week (http://vencoreweather.com/2015/03/10/930-am-winter-like-pattern-to-resume-after-spring-break/). While it is a long shot to get a blizzard in this region this late in the season (or frankly at any time of year), the amazing storm of 1958 proves that it indeed can happen.