2:20 PM | **”It ain’t over till it’s over”…cold pattern continues well into April and snow still a threat**
Paul Dorian
12Z GEFS 850 mb temperature anomalies averaged out over the 5-day period from March 30th to April 4th (days 4-8); map courtesy NOAA/EMC, tropicaltidbits.com
Overview
There will be a noticeable warm up over the next few days in the Mid-Atlantic region, but it looks like this will be just a temporary spring tease as colder-than-normal conditions are likely to return for the first ten days or so of April and some signs point to a colder-than-normal pattern continuing much longer than that - perhaps even into May. In addition to the cold, there will likely be some close calls with respect to snow in the I-95 corridor in April and it is just too early to give an all clear on that particular front.
12Z GEFS 850 mb temperature anomalies averaged out over the 5-day period from April 3rd to April 8th (days 8-12); map courtesy NOAA/EMC, tropicaltidbits.com
Discussion
Temperatures will climb noticeably in the Mid-Atlantic region during the Wednesday-to-Friday time period of this week – likely to 60+ degrees for highs in DC, Philly and NYC – but this warm up will be accompanied by occasional showers. At the same time the eastern US warms, a much colder-than-normal air mass will be building across central Canada. It is from this source cold region that cold air outbreaks will originate over the next few weeks before they drop to the south and east and likely result in numerous days around here with below-normal temperatures. Not every individual day will be colder-than-normal in this upcoming pattern, but the average over 5-day periods during the month of April are quite likely to be below-normal in the DC-to-Philly-to-NYC corridor (three example 5-day periods shown). A cold frontal system will push through the region this Friday and usher in the first wave of colder air for the upcoming weekend and then another blast may arrive early next week and then a third one late next week.
12Z GEFS 850 mb temperature anomalies averaged out over the 5-day period from April 7th to April 12th (days 12-16); map courtesy NOAA/EMC, tropicaltidbits.com
April 6-7, 1982 and upcoming threats for snow
Can we get accumulating snow in the Mid-Atlantic region during April…sure, and one such example took place on April 6-7, 1982. This particular event turned into an all-out blizzard for New York City and the baseball season was delayed a week in many cities from Baltimore-to-Boston. This storm resulted in significant snow of more than a foot in many places from Pennsylvania-to-New England and winds gusted to 70+ mph in spots during the storm. Also, record cold poured in on the back side of the storm with many places falling to 25 degrees below normal for early April shortly.
There will be at least a couple different systems to monitor next week as our pattern turns colder and snow cannot be completely ruled out with any of them. One threat of snow may arrive early next week (Monday time frame) and another one is possible at the end of the next week after the arrival of a very chilly air mass from central Canada and this one would just happen to coincide with the anniversary of the great April (6-7) snowstorm of 1982. It looks like there may be an impressive digging trough in the eastern US and there will be cold air around - stay tuned.
Meteorologist Paul Dorian
Vencore, Inc.
vencoreweather.com