By Alex Sosnowski, AccuWeather.com Senior Meteorologist
March 31,2016; 9:44PM,EDT
Following a very warm start to spring over the eastern United States, why is cold air returning in April, when temperatures typically trend upward?
During much of March and long stretches of the winter for that matter, arctic air had been locked up across central and northern Canada.
"Persistent high pressure aloft near the Atlantic coast prevented cold air from moving southward out of Canada and into the eastern United States," according to AccuWeather Senior Meteorologist Brett Anderson.
The pattern allowed a west to east flow of air to dominate across the nation much of the time.
The vast majority of the nation had temperatures averaging 2-6 degrees Fahrenheit above normal during March.
In parts of the Plains, Midwest and South, temperatures were 6-8 degrees above average.
"Starting this weekend and into part of next week, high pressure aloft will shift to the western United States," Anderson said.
The polar vortex will also shift its position a bit farther south and will open the doorway for cold air to be scooped southward and into the Upper Midwest and Northeast.
"April sunshine, a lack of snowcover and many ice-free areas on water bodies along the way will modify that air as it move southward," according to AccuWeather Senior Meteorologist Brett Anderson.
"However, the cold, dry nature of the air, combined with gusty winds will pack a sting at times."
Some lake-effect snow and snow showers will occur.
"There will also be a couple of clipper storms that move through with areas of general, steady snow," Anderson said.
Since the anchor for the cold air will hover near Hudson Bay and pivot, the cold blasts will be limited mostly to the northern tier and will be brief.
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Two to three shots of arctic air will rotate through the northern tier states into next week with exponentially less extreme cold farther south, where progressively more mild air from the Pacific Ocean will be mixed in, AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.
The first push of arctic air will be the most robust due to gusty winds and will slash temperatures by 10-30 degrees from one day to the next, from Friday to Saturday around the Great Lakes and from Saturday to Sunday in the Northeast.
As the arctic air approaches and sweeps in, winds could be strong enough to cause sporadic power outages.
The waves of arctic air will bring one or more days with highs in the 20s from the upper Great Lakes to northern New York state and northern New England. Nighttime lows in this swath will range from the single digits and lower teens.
Farther south, highs on multiple days will be lower to middle 40s from Chicago to Detroit, Pittsburgh and New York City.
AccuWeather RealFeel® Temperatures will be 10-20 degrees lower than the actual temperature at times.
During the pattern, temperatures can dip to below freezing on one or more nights as far south as Philadelphia and Washington, D.C.
The pattern with the waves of arctic air will break down during the middle of April and will allow more seasonable Pacific air to take over and break the stagnation.
However, typical of April, there may be a back-and-forth fight going on in the atmosphere for a time.
While days with strong April sunshine will bring warmth on occasion, episodes of clouds, rain and flow of air off chilly waters will contribute to below-average temperatures at times.
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Donnie Boston ·
Time to move out of this friggin area, period!
John C. Hitchner Jr. ·
The
long range forecast calls for below average temperatures for the next
six to ten weeks,enjoy today and tomorrow while it lasts because this is
probablty the last we'll see of it until June,this always seems to
happen whenever we have an early easter in March
Claude Ouellette
everyday
the weather trends for 2 weeks, always changes for the worst, & it
pisses me off, going into April 14th and only low single digit for this 2
week period.
Cory Morrison ·
Works at Fortinos
The first half of April 2016 is looking more like 2007 and 2003.
Grant McGuire ·
My
worry is that if the cool & rainy pattern keeps up, it will put a
hinder on our warming. If the sun has to dry out a saturated ground, it
can't warm the air as quickly. Look back at 2015: The warmest periods
(i.e. late spring, late summer), were fueled by a lack of precip.
Grant McGuire ·
And most importantly, it really helped to wipe away the Jan-Mar 2015 temp defecit
Cory Morrison ·
Works at Fortinos
Grant McGuire I hope the Jan-Mar 2016 positive departure is not wiped away.
Eric Bailey ·
I'm not looking forward to a freezing april. I am waiting for a heat wave this summer.
Dani G. Al-Halabi ·
The
best thing is getting a low pressure riding the coast in time for cold
air. If it would hold precipitation such as BLIZZARD '16 that would be a
record crusher .
Works at Fortinos
Hoping that the pattern eases after April 10th-ish.
Rocco Salvemini ·
They said mid-April is when the pattern changes. There are 30 days in April. Tax time is the halfway point
I'm
hoping this year will continue to go in line with 2010, even though
early April is going to be chilly. A cold first half of April doesn't
really mean we have to abandon 2010 as an analog. Just as long as the
overall pattern is similar with that year going forward. No two years
are going to be carbon copies of each other.
And 1983 never failed us as an analog this year. In fact, the winter was very similar to 1982-83. I don't think spring will be as cold as 1983, but we still may see the 1983 resemblance in our spring pattern. Or we could have shades of both 1983 and 2010. It's still early but this is my GUESS based on the current overall pattern, historic trends and analogs: (I really don't have much confidence for May-June)
- cold first half of April, near to milder than average second half
- cooler early May, warm mid-late month.
- slightly warm June.
- hot July-September.
- mild October.
- chilly November.
And 1983 never failed us as an analog this year. In fact, the winter was very similar to 1982-83. I don't think spring will be as cold as 1983, but we still may see the 1983 resemblance in our spring pattern. Or we could have shades of both 1983 and 2010. It's still early but this is my GUESS based on the current overall pattern, historic trends and analogs: (I really don't have much confidence for May-June)
- cold first half of April, near to milder than average second half
- cooler early May, warm mid-late month.
- slightly warm June.
- hot July-September.
- mild October.
- chilly November.
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