Philadelphia

Will the Cold Stretch Continue in April?

NBC10 First Alert Weather meteorologist Glenn Schwartz looks ahead to April.

A LONG COLD STRETCH IN MARCH
After Monday the 26th, we have now reached 22 STRAIGHT days with below “normal” temperatures in Philadelphia. That’s an incredible streak, especially considering that only two of those days were REALLY cold. It takes a consistent type of weather pattern to accomplish this. And, in an era of overall warming, that makes it even more impressive.

Below is a map showing average temperatures compared to normal for just the past week alone:
 
[[477993953, C]]

COLD APRIL-AT LEAST TO START
We surely will see temperatures warm during April, right? After all, the sun angle is so much higher than in February or March. But, how did March end up colder than February? And that happened for the 2nd year in a row!

Here is the temperature pattern based on an “ensemble average” for next Friday, April 8th. That looks even colder (compared to normal) than the current pattern!
 
[[477994023, C]]

That is a huge area with below normal temperatures. There may be a warm day or two in the first half of April, but the overall picture is a cold one.

Here is the comparison of February and March (so far), along with the averages for April:
            

              Average temp    “Normal”    Snow    “Normal”
February        41.6            35.7        1.4”       8.8”    
March            38.3            43.5        15.2       2.9”
April                ???            54.0        ???        0.5”

So, even if April averages waaaaay below normal temperatures, it still has to be a LOT warmer than March has been. But notice that our “normal” April has 0.5” of snow. It’s not that unusual to get some flakes. Just 2 years ago, we had 0.3” on April 9th. Our record for April is an incredible 19.4” on Easter Sunday, April 3, 1915. Can you imagine that? The latest date of measurable snow on record was April 27, 1967. And the latest date with even a trace of snow was May 8, 1947.

COULD WE EVEN SEE FLAKES THIS APRIL?
We could, especially with the upcoming pattern. Take a look at the upper-air pattern predicted by the European model (the world’s best overall)

[[477994103, C]]
 
Those areas of dark blue in Southern Canada represent pressures Waaaaay below normal. And the red and purple colors in Alaska and Northern Canada show above normal pressures. Those blues mean another visit by the dreaded “Polar Vortex” close to the Canadian border. It is very unusual to have a pattern this extreme in April.

Any snow would not come this Easter Sunday, but the pattern later next week could be more favorable. At least we know it’s not unprecedented.

Glenn “Hurricane” Schwartz
NBC10

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