Sunday, December 22, 2013

A Mid (Well, Now Late) December's Blog Post: A Warm Welcome for the 2013 Winter Solstice

**Entry updated 2:13PM 12/22/2013 for clarity and new info.**

Spherically-arrayed Christmas light decorations, of a sort, downstairs at Number 9, Washington, D.C., 12:08AM December 22, 2013.


I was a bit of a mess a bit earlier tonight. I had a nice solo dinner at Trio -- where the waitress really appreciated my tip based on the $60 I left on a bill of $47 and change -- and then I went to No. 9, where I had a nice conversation with bartender A. and bartender D. However, it was necessary for me to get home quickly owing to [SEE TRIO / DINNER AT].

Of note, I went to the gym on Saturday and had a full workout, including 1 hour / 5.7 mile jog and nearly an hour of light-to-moderate machine weight-lifting, and a swim (although my swim was 20 min. instead of 30 min.).

However, I was a bit concerned by the fact that my weight suddenly notched DOWN another pound to just about 141.5 pounds. I am down now 42 pounds in the most conservative estimate possible and more like 46 pounds in terms of fat loss. I really don't want to go any lower.

As it is, I won't be at the gym again until at least Thursday owing to the Christmas holiday visit to my mom's place, and possibly not until next Saturday.


The Weather: Record Winter Solstice Warmth

It is an absurdly warm and rather breezy night for late December and first full calendar day of winter under a fast-moving, broken, low overcast with a temp. of 68F at KDCA at the 1AM hour after having set a record maximum temp. on the 21st of 72F.

The old KDCA record high maximum temp. for Dec. 21st was 68F set in 1923. KDCA also tied the record high minimum (that is, overnight low) temp. record for Dec. 21st of 51F set in 1895. Both of these are pre-National Airport D.C. records. The full D.C. record goes back to 1871 with official record-keeping starting at the airport either in 1941 or 1943 (I've never been able to figure out exact date).

Today (Dec. 22nd, 2013 / Sunday) will surely set both a record high maximum and minimum temps at KDCA. The current ones are 72F set in 1889 and 49F set in 1923, so both are pre-airport records).

The 12Z 12/21/2013 NAM showing 2-meter minimum temperatures across 3-hour period centered on hour 18 / valid 6Z (1AM EST) Dec. 22, 2013 for the Sterling (LWX) CWA. The graphical plot was created by WeatherBELL.


KBWI and KIAD also hit record highs on the 21st both on the maximum (daytime high) and minimum (overnight low) ends. KBWI had a high of 71F and a low of 54F on the 21st, respectively (old records were 62F set in 2011 and 52F set in 1895); and KIAD had a high of 70F and a low of 51F, respectively (old records were 61F set in 2011 and 46F set in 1998). (Updated: KIAD has already done so even before I posted this entry with a 69F reading at the 3AM hour -- see below.)

(This was rewritten for clarity as the original version was garbled.) Both KBWI and KIAD are likely to set record high max. and record high min. temps once again for Dec. 22nd.)

For KBWI, these are 70F set in 1889 and 48F set in 1931, respectively. For KIAD, these are 67F in 1984 and 49F in 1990, respectively. The KBWI records are both pre-airport ones. The full Baltimore record goes back to 1871 with official record-keeping at the airport starting no earlier than 1950 when the airport opened.

KIAD records, while only going back to 1960 when the airport opened, have been continuously kept there.

Updated 2:13PM 12/22/2013: So PRELIMINARILY it looks as though KDCA reached 72F, tying the daily record high; KBWI reached 71F, surpassing the previous daily record high; and KIAD reached 71F, easily breaking its old daily record high. These occurred between 7AM and 9AM this morning (!). The issue will now be whether the overnight record high min temps. are broken before midnight. This seems likely. Temps should start getting back to normal tomorrow.

For a broader perspective on how warm it was across the Eastern / Southeastern U.S., see this CWG entry.

The 12Z 12/21/2013 NAM showing 2-meter maximum temperatures across 3-hour period centered on hour 33 / valid 21Z (4PM EST) Dec. 22, 2013 for the Sterling (LWX) CWA. The graphical plot was created by WeatherBELL.


At it is, a strong frontal boundary is ever-so-slowly moving eastward and a pattern change will end this record warmth. Heavy rainfall is progged for Sunday night into Monday morning for the immediate I-95 corridor as an impulse forms along the frontal boundary.

A portion of the U.S. radar mosaic (in composite mode) for parts of the United States including the mid-Atlantic, Southeastern U.S., Appalachians, and Ohio River Valley valid at 0628UTC (1:28AM EST) December 22, 2013.


In fact, as of 4AM -- even before I post this -- a severe thunderstorm watch has been expanded to include the entire Metro D.C. and Baltimore areas. That's rather unusual for late December in the wee hours of the morning. Furthermore, the temperature is 68F at KDCA as of 3AM, which is within 4F of the Dec. 22nd daily record high (see above). As for KIAD, it is at 69F at 3AM -- so it is ALREADY 2F above its Dec. 22nd daily record high.

Updated 2:13PM 12/22/2013: See update above to note preliminary highs so far.

The Sterling (LWX) NWS county warning area (CWA) main webpage advisory map as of 3:14AM EST December 22, 2013 showing the severe thunderstorm watch in effect for much of the region.

I'm not exactly sure why a severe thunderstorm watch was issued. As the 8:30PM EST LWX discussion noted, "THIS REMAINS A LOW CAPE AND HIGH SHEAR EVENT SO WE DON'T ANTICIPATE A LOT OF SEVERE WEATHER WITH THIS SETUP." I think they issue these watches as an extra layer of precaution.


Of note, both the 18Z Dec. 21st and 0Z Dec. 22nd NAM and GFS models suggest some snow flurries / snow showers in our area for Christmas Eve. The new 6Z Dec. 22nd NAM also shows it. I'll believe it when I see it.

Left: The 6Z 12/22/2013 NAM at hour 66 / valid 0Z Dec. 25, 2013 (7PM EST Dec. 24, 2013) showing 6-hour precip., MSLP, and 850mb temps.

This scenario would definitely produce a dusting of snow (the -10C 850mb isotherm is well to the south of the region) and there is at least 0.01" QPF.


Speaking of Christmas snow, Sterling / LWX has a very good write up about the history and climatological odds of a "white Christmas" in the Washington and Baltimore areas -- with the numbers focused on KDCA (and its pre-airport records) and KBWI (and its pre-airport records).

Map of the Lower 48 showing the historical probability of a "white Christmas" based on 1981 - 2010 data. The different color shades indicate different probabilities (percentages).


Oh, yes, FYI, one last item about the current warmth: Below are the all-time warmest December readings (I don't think we will reach those tomorrow):

KDCA: 79F - Dec. 7th, 1998 (source here)
KBWI: 77F - Dec. 6th and 7th, 1998 (source here)
KIAD: 79F - Dec. 6th, 1998 (source here)

I don't have the all-time record max low temps for December, but we may very well break those.

Let me just say that no matter how warm it gets during the day in the DJF period, it still gets chilly at night, and one needs a jacket.

Furthermore, these really warm days at this time of year result in the pavement getting wet at night as water vapor condenses out of the air in the layer immediately above the asphalt as the air radiates away its heat.


Winter Solstice and the Length of Day ...

So yesterday (Dec. 21st, 2013 / Saturday) was the actual winter solstice, the "shortest day" of the year in terms of sunlight. However, the actual earliest sunsets in our part of the world (i.e., at our latitude / 4:46PM EST for Washington, D.C.) occur about two prior to this and the latest sunrises (7:27AM EST for Washington, D.C.) occur about two weeks later.

A table of the latest sunrise and earliest sunset times in Washington, D.C., in the three week period on either side of the winter solstice. This table was taken from the CWG entry linkted below and was put together by Justin Grieser .


Conversely, the earliest sunrises precede the summer solstice by about two weeks and the latest sunsets follow it by about two weeks. It's just that the net difference is the shortest and longest, respectively, on the solstices.

For an overview of this, see this CWG entry (link embedded): Winter Solstice 2013: Shortest day of the year, but sunset already creeping later.

Sunrise and sunset times and the length of day (i.e., duration of daylight) for selected cities arranged by latitude on the day of the Northern Hemisphere winter solstice.


And for a more technical discussion of reasons involving elliptical orbit of the Earth (i.e., Kepler's Laws of Planetary Motion) around the Sun and the approximate 23.5 degree tilt of the Earth on its axis (obliquity and resulting significant changes in right ascension) that alters the Equation of Time offset, see this Atlantic Monthly article (link embedded): The Astronomical Hijinks of the Shortest Day of the Year.

Schematic diagram showing the axial tilt or obliquity of the Earth.


OK, that's all for now. I'm feeling less of a mess now.

I'm going to try to update this blog tomorrow, but I have a lot of work to do on the big Hawaii project, so I may not actually update it. In that case, I would not update the blog until Monday night. As for the planned visit to the National Zoo's ZooLights with Chris H. and possibly Gary, I'm kinda doubtful that is going to happen based on the likely weather.

The ZooLights display the entrance to the National Zoo, Washington, D.C., 6:32PM December 20, 2010.

I last went to ZooLights with my former friend K. back in December 2010, she of the Hippograms blog with her late boyfriend, Rick. I wrote about the ZooLights trip in this entry.

Oooh, she turned on me something terribly in Aug. or Sept. 2011. For starters, it was difficult being her friend given how instantly argumentative she was. It just didn't mix well with my own personality, and though I made every effort to appease her and be her friend, eventually I got angry at her in a phone call, a fact that she eagerly used as an opportunity to demonize and turn on me. Regardless, I'm still glad that I was able to be her friend -- to be there for her, to the extent that I could -- in the immediate aftermath of Rick's death.


OK, that really is all for now. My next update will likely be on Monday night. G'night.


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