March 25, 2013 Storm Summary

March 25, 2013 Rain, Snow

1748The last widespread snow event of the winter of 2012-13 affected the region on March 24-25, producing widespread rain and snow in the Mid Atlantic. The storm was forecast to produce snow accumulations in the NYC area, the second such storm to do so in the second half of March, but instead stayed south with little to no accumulations.




March 25, 2013 Storm Archive

March 19 – Winter Pattern Continues Into Spring
March 20 – Some Snow Tonight, Next Week’s Storm
March 21 – Pattern Likely To Continue Into April
March 24 – Some Snow Tomorrow


Storm History

mar25trackThe system affected the region in two waves; the first was from a low pressure tracking parallel to the coast of North Carolina, then extending offshore, bringing an initial round of precipitation into the southern Mid Atlantic on Sunday, March 24. The second wave moved into the region on Monday, March 25, as the primary low pressure tracked slowly into Ohio while transferring its energy to the coastal low pressure, which redeveloped off the coast of Virginia and continued to track northeast, exiting the region  early on Tuesday, March 26.


Forecasting The Storm

This section will be added soon.


Storm Impact in the Northeast

Regional radar image from 1:48 PM 3/25, from the National Weather Service. Moderate snow fell over southern New Jersey, with a light rain/snow mix elsewhere.

1748The storm affected the region in two waves, the first was a southern low pressure that tracked off North Carolina, which produced moderate snow over southern Virginia on Sunday, March 24. The second wave then affected the rest of the Mid Atlantic on Monday, March 25, as moderate to heavy snow spread into West Virginia and SW Pennsylvania. As the coastal low pressure developed during the day, heavy precipitation spread into southeastern PA and southern NJ.

While temperatures aloft were below freezing, the combination of a stale cool air mass, higher late March sun angle, and marginal precipitation rates resulted in the precipitation type largely depending on the intensity of the precipitation, with light precip falling as rain or rain/snow and heavy precip falling as snow. Widespread snow spread into south-central NJ and SE PA on Monday morning as precipitation collapsed over Pennsylvania. The precipitation shield stalled over the NYC area, where light rain fell, mixing with snow with any burst of moderate precipitation, while most of the region changed over to rain by the late afternoon and evening except for southern NJ, which continued to see moderate snow, and Pennsylvania with scattered rain/snow showers. The storm ended overnight as the coastal low moved offshore.


Storm Snow Totals

Below is an estimated snow total map, based on storm reports from the National Weather Service.

mar25snowAs this storm was in late March, it produced significant snow totals in the Mid Atlantic relative to the time of year; widespread totals of 3 to 8 inches were observed in southern Pennsylvania and Virginia, with higher totals over the higher elevations up to a foot or locally higher. As previously noted, the storm was originally forecast to produce snow in the NYC area, but the heavy precipitation stayed to the south, leading to a light rain/snow mix with little to no accumulations in the area. In New Jersey, most of the snow stayed south of the area, with 1 to 4 inches over central-southern New Jersey, locally higher.

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