Cold and Colder…and Not That Cold

Merry Christmas and Happy New Year!

Laura readers, ever notice that she hardly ever talks about being sick?  Other than a near-fatal bout with diphtheria in The First Four Years and the “fever ‘n ague” (malaria) in Little House on the Prairie, and the scarlet fever illness that was implied between On the Banks of Plum Creek and By the Shores of Silver Lake, Laura never talked about getting sick.  Maybe all of that isolation in cold, remote houses limited the family’s exposure to germs.  Maybe she had a whopper of a constitution (she did live to age 90, after all).  Or maybe she just didn’t talk about boring colds in her books.  If only I had her fortitude, either to not get sick or to not talk about it!  Well, at least this cold has me sitting still long enough to write a little.

Our temperatures today in Omaha only reached the 30s, with lows in the teens last night and again tonight.  This is the coldest weather we’ve had in a few weeks, and it’s still only just getting down to normal temperatures.  I wrote a little web story about why the weather on the Plains has been so warm for much of the winter, but I’ll give the cliff’s notes here, too.

One reason for the warmth is that the snowpack across the Plains remains scarce.  In fact, there simply isn’t much snow at all from North Dakota to Texas and from the Colorado plains to the Great Lakes.  When there is snow on the ground, the sun’s energy is reflected more easily… and what is left of the sun’s energy goes into melting that snow.  Without the snow on the ground, the sun’s energy can go right to heating up the ground and the air.

Another reason for the warmer weather has been the persistent weather pattern, with the jet stream running pretty much west to east instead of dropping out of Canada.  This is related to a pattern called the North Atlantic Oscillation (or NAO).  When the NAO is positive, the flow across the central and eastern US into the Atlantic Ocean tends to be more straight east to west, and those areas tend to be warmer than normal.  In a negative NAO, the opposite is true: a low pressure area sets up in the eastern US, with flow out of the northwest in the central and eastern US, which dumps cold air into those areas.  The last two winters (2009-10 and 2010-11) were dominated by negative NAO (in fact, the winter of 2009-10 was one of the strongest negative NAOs since the mid-1800s, if not the strongest).  This winter, so far, we’ve been dominated by positive NAO.

By the way, in case you’re wondering (and I was!), the Long Winter of 1880-81 was dominated by a strong negative NAO.

So even though it’s not too cold, it feels cold… and I have a cold, which makes it feel colder.  But I also have a warm fire, a lovely Christmas tree that is about to come down, and what remains of the chicken soup I was smart enough to make yesterday when I first got a scratchy throat.  And the cold was kind enough to hold off until after our New Year’s Eve festivities.  The mild winter continues in the heartland, and forecasts indicate it will continue for at least the next week.  Better make hay while the sun shines!