Why so cold? Blame the North Atlantic Oscillation


I received this question in a reader comment a little while ago. Seemed like a fair one:

"Why so cold this year Frank?  Jet stream - El nino?  Any indication that it will continue?  Wasn't planning a break but with these temps may break up the winter with a trip to the Keys."

Check before you fly off to the Keys. The forecast there for Sunday calls for a high of 57 degrees and a low of 46. I've been there in that kind of weather. It ain't no picnic.

As for why it's been so cold, I sent the question to Chris Strong, at the National Weather Service Forecast Office in Sterling. Here's his reply:

"The North Atlantic Oscillation is the reason for recent cold. It is a cycle that to a large extent governs how cold we are here at any given time.

"Unlike the El Nino/La Nina cycle which happens over years, the NAO cycles over weeks.  Here is a link to the recent trend on the Climate Prediction Center's webpage... http://www.cpc.noaa.gov/products/precip/CWlink/pna/nao_index.html

"However, I would caution that we are grading 'cold' on the skewed scale compared to our relative mild weather over the past several years. A few thoughts:* November was over 4 degrees above normal (very mild), which will also alter people's impressions going into winter.

* Looking at Dec 1-Jan 7, we are 27th coldest in Baltimore's records with a 33.7 degree avg. 1876-7 was coldest at 26.0 degrees, but more recent colder were 1989-90 27.8 (#3) and 2000-01 at 29.5 (#5).

* December was a few degrees below normal, but was just our 36th coldest on record.

* The first week of Jan has been cold, but as the first week of January goes, it was just the 24th coldest on record.

* Another important point....no temperature records have been broken this winter in Baltimore."

So, maybe it's not so cold, after all. And if it feels cold, just figure the NAO can change over a period of weeks. It can't last forever.

(AP PHOTO/Steve Ruark/Jan. 8, 2010)

Copyright © 2018, The Baltimore Sun, a Baltimore Sun Media Group publication | Place an Ad