Saturday, December 1, 2012

Yet Again, Weatherless in Washington, D.C. -OR- Keep On Dreaming of a White Christmas

Lighted Christmas decorations fill a yard in the 1600 block of 16th Street NW, Washington, D.C., 5:14PM, December 1, 2012.

I'm not sure if this is some sort of inn or bed-and-breakfast place, or if it is associated with the Church of the Holy City. There are frequently decorations in the yard for various holidays including Halloween and Thanksgiving, too. There also is always a lot of activity in the place. There is no sign nor any address number, though it is the 1600 block.


Saturday night and I'm home, eating some dinner, watching TV and quite tired but planning to go to No. 9 and/or Nellie's tonight.  But this entry is dedicated to the weather ...

We continue to be in a dull, nothing "no weather" weather pattern here in Washington, D.C., and environs. It has been this way ever since Hurricane / Superstorm Sandy, which just gave us a lot of rain but no wind-induced damage.

Screen capture image of the NWS radar mosaic (composite mode) for the Lower 48 United States, 0238UTC (9:38PM EST) 02 Dec. (1st), 2012. Click on image for larger version.


Now before I continue, let me be clear that when I complain about the lack of "weather," I don't mean that I want violent storms -- Hurricane Sandy-like destruction, tornadoes, lethal cold, or flooding rains.

NWS/NCEP/HPC 12 hour surface forecast map for the Lower 48 United States, valid 12Z (7AM EST), Dec. 2, 2012.


Instead, I simply mean that I desire a variety of weather -- a gusty and showery day, a snowy night (accumulations of several inches), a sunny morning followed by a rainy afternoon, and so on. But as I said, the current pattern features mostly sunny days and chilly night, temperatures average climbing to slowly above normal. There might be some fog (ooooh...)

Also, we are way below normal on precip. this year -- presently -7.38" at 29.42" at KDCA or 20.0% below the  year-to-date normal of 36.80". We would be about 12" inches (1 foot) or -32% below normal but for the 4 to 8" deluge areawide from Hurricane Sandy.

More generally, the weather in Washington, D.C., sucks most of the time regardless the time of year. In summer, it's disgustingly hot and gross (with the stench of a swampy sewer), suffocatingly humid yet no rain for the most part, except punctuated by a short-lived, violent outburst of storms about every 2 to 4 weeks (that usually manage to miss KDCA in terms of "official" precipitation). In late fall and through the winter for multiple years at a stretch, it is bland, blah, dull, partly cloudy, and somewhat above normal temperatures with no snow.

Part of it has to do with the city's location -- too far inland for nor'easters, in the lee of a mountain range that downslopes (squashes) any "weather" from the west or northwest, and a bit too far south. The only worse large metropolitan area in the Eastern United States in this respect is Atlanta, a dreadful city in many other ways as well.

Unless the Gulf of Mexico or, less frequently, the Atlantic Ocean "opens up" with deep-layor advection of moisture, Washington, D.C., and its environs, basically just get the leftover bits of "weather" that have crossed the continent. Or as someone once remarked (I can't recall who), our area is forever "chasing the weather."

Global Land-Ocean Temperature Index, 1880 - 2011 (source here).


The other part has to do with global climate change and the slow but steady disappearance of winter in the past 25 years punctuated by the odd years when some combination of negative North Atlantic Oscillation (NAO) and negative Arctic Oscillation (AO) or Northern Annular Mode and warm ENSO (to supply the necessary moisture) can create a cold and snowy winter here (as in 2009 - 2010).

Note: The NAO and AO can rarely be out of phase. See below.

Highly stylized schematics of the Negative and Positive Phases of the North Atlantic Oscillation (NAO).


Schematic of the Positive Phase of the Arctic Oscillation (AO) and its associated stronger  (colder) Arctic polar vortex.

(Yes, "Arctic" is misspelled in this diagram.)


500mb geopotential height anomalies associated with a positive AO.


Schematic of the Negative Phase of the Arctic Oscillation (AO) and its associated weaker (warmer) Arctic polar vortex. 


500mb geopotential height anomalies associated with a negative AO.


Side-by-side comparison of a positive and negative AO situation (from 2010).


Side-by-side comparisonof positive and negative NAO (from 2010).


The AO and NAO are frequently (anywhere from 75% or more of the time) "in phase" -- positive / positive and negative / negative. But there are rare instances where they are not. In order for that to happen, the polar vortex must be "knocked off" from being centered on the geographic North Pole and is "pushed" into either the eastern hemisphere (over Siberia) or the western hemisphere (over northern Canada) and thus the AO is "out-of-phase" with the NAO.

The Australian Embassy at Massachusetts Avenue and 16th Street NW, Washington, D.C., 5:21PM, Dec. 1, 2012 with its very Aussie Christmas decorations. Of note, the "Santa" lighted had on red velvet short as he was "mushing" his "herd" (troup?) of kangaroos.

To bad Fifi doesn't come around this blog anymore. She might have an interesting observation to make.

I was walking to the gym this evening when I took that picture and the entry lead one.


I am guessing that the winter of 2012 - 2013 will be similar in the mid-Atlantic region to last winter when there was one major storm around Halloween (this year, that would be Hurricane / Superstorm Sandy) and then another around April 1st, and NOTHING in between.

Looking ahead for the next 7 to 10 days, the main operational GFS model that I view (I can't access the high-resolution ECMWF "European" model) always shows fantasy storms at day 8, 9, or 10 that always vanish once within the 6 day timeframe.

Here is the 18Z 01 Dec. 2012 GFS run valid at hour 276 -- that is, 11-1/2 days from now and thus all-but-useless as an actual forecast -- at 6Z (1AM EST) Dec. 13, 2012 showing what would be an impending tremendous Arctic outbreak over the eastern U.S.
Note the -30C closed isotherm at 850mb over west-central Ontario.  


The current dull, mild pattern always thrills the local weather-casters, in particular the Sue Palka-cabra creature, the bad-tempered Ms. Snake Eyes herself.

"And you know what, Morris? Good news. I now this that it's looking like the weekend will be dry, sunny, and warm.

Here is the Palka-cabra's dream climate.


Furthermore, the vocational NWS forecasters at Sterling LWX mostly chime in with the same sentiment. If the Mount Holly PHI crew make the weather excessively dramatic (though it does tend to be a lot more interesting in their county warning area), the Sterling crew suck the joy and happiness, indeed, the life itself out of "the weather." I rarely read their discussions anymore.

Then there are the Accu-Weather and Weather Channel corporate-run outfits -- the former based on the free market in its perfect libertarian form graduate student indentured servitude; and the latter a sort of perpetual motion machine of contrived frenzy, but always in an American family values and Republican Party-friendly way with suitable commercial breaks.

Oh, and as for Yuletide season snow, invariably we're going to have to do a frickin' hokey pokey dance about "the odds of a white Christmas" -- and Sterling, of course, will get in on the act.

A map showing the probability of a white Christmas (i.e., with 1" or more of snow on the ground) on Christmas Day.

In short, we ain't gettin' no snow on Christmas. There isn't the SLIGHTEST chance of a "white Christmas" in Washington, D.C. -- so keep on dreaming.

If you want snow on Christmas, you have to go find it in a snowier / colder climate. End of story.

Of note, there hasn't been an actual "snowy day" (as in a heavy, sustained snowfall) on Christmas day proper in the Washington, D.C.,  area since Dec. 25, 1969 when 4.3" fell at KDCA. I was but 1 month old in New Jersey -- and it snowed heavily there as well.

OK, that's all for now.



Nikita said...

Can you explain to me in simple terms the cause of polar vortex? It's difficult for me to understand.

Nikita said...

Can you explain to me in simple terms the cause of polar vortex? It's difficult for me to understand.