Historic Warmth, Thursday, December 24, 2015

Record breaking warmth would not typically warrant an analysis in a monthly summary. However, the warmth which occurred on Christmas Eve 2015 was exceptional as high temperatures surged into the upper 60s to lower 70s with dewpoints climbing to 60° in a set up that was almost identical to the set-up which lead to a similar day of record warmth on Saturday, January 6, 2007, when temperatures last surged into the lower 70s during meteorological winter, which are the months of December, January, and February.

Records @ Albany
High Temperature: 72° at 2:20pm - Sets a new record high for the date, previous 57°/1941

Highest December Temperature on Record, previous 71°/December 29, 1984

Highest Temperature on Record for Meteorological Winter (Dec, Jan, Feb), previous 71° January 6, 2007, December 29, 1984, and January 13, 1932

Record High Minimum of 43° Tied, previous 43°/1931

Record High Mean Temperature for the date of 57.5°, previous 47.5°/1931


Noteworthy: Christmas Eve. 2015 was warmer and more humid than the 4th of July 2015 when the temperature at Albany only reached 70°

With December 15, 2015 included , the temperature to date has only reached or exceeded 70° four times in recorded history at Albany during meteorological winter. The only other three times this has occurred was on January 6, 2007, January 13, 1932 and December 29, 1984, when the temperature at Albany climbed to 71° on each of those days.

Set Up
A unique but not unprecedented and readily identifiable set of circumstances came together on December 24, 2015 to allow for spring like warmth to occur.

First, the air flowing into and over the region was not in any way cooled, as it often is in late December, by a snow pack on the ground. The exceptionally mild fall continued through December with no snow falling in the Capital Region or for that matter anywhere in the Northeast outside of the Lake Ontario and Erie lake effect regions. Further, temperatures in the two days preceding Christmas Eve. climbed into the 50s in a pre-existing very warm air mass for the time of the year setting the stage for the record warmth on the 24th.

Second, a warm front, preceded by a period of rain from the 23rd through the early morning hours of the 24th, moved north across the region prior to daybreak putting eastern New York and New England in an even warmer sector of air. (Temperatures at 850 mb climbing to 13° to 15° C) The approach and passage of a dry weak cold front/wind shift line during the early afternoon (approximately 2-3pm) allowed deeper mixing of the atmosphere to develop and a subsequent wind shift into the west, southwest. (A southwest wind downslopes into the Capital Region-Hudson valley off the Catskills which causes some compressional warming and drying of the air resulting in decreased cloud cover and warming.) The result of the wind shift and increase in sunshine due to the cloud deck rapidly thinning out by the late morning and the early afternoon, coupled with the deep mixing, was a surge in temperatures into the upper 60s to record smashing lower 70s. Albany's record high of 72° occurred at 2:20pm during this period. Dewpoints also climbed, peaking right at 60° at Albany between 11am and 2pm giving the day a true spring like warm and muggy feel. Only gradual cooling occurred through the afternoon with low 60s by 5pm, then low 50s by 6pm, and finally the upper 40s by 11pm to the low of 43° at 11:59pm.

Warm weather continued through Christmas Day with partial sunshine and highs climbing into the upper 50s.

NOTE: The antecedent mild conditions throughout the fall which continued through December across the region were largely due to a dominant -PNA pattern (Pacific North American), along with a +NAO (North Atlantic Oscillation) and +AO (Arctic Oscillation) jet stream pattern, where a colder and stormy low pressure trough prevailed across the western United States with a warm ridge of high pressure dominating the east. Contributing to the degree of warmth was likely the occurrence of the exceptionally strong and ongoing El Nino, ranked among the top three strongest on record in the equatorial Pacific. Although the jet stream pattern in December did not closely match a "Typical" El Nino jet stream pattern, as a ridge across the western United States has been shown to be more favored with weak and shallow trough across the east, the strength of the El Nino (meaning the high degree of above average ocean temperatures) likely was responsible for transferring additional heat from the ocean to the northern hemisphere atmosphere influencing and increasing the level of warmth, warmth which likely would have occurred regardless of whether there had been an El Nino in progress or not. And the warmth in December was considerable as most climate reporting stations in the Northeast measured their warmest Decembers on record.

Temperature, Dewpoint, Wind Plot For Albany, Thursday December 24, 2015

TIME
TEMPERATURE
DEWPOINT
WIND DIR/SPEED- Weather
12am
54
51
South 8 mph - Lt. Rain, Fog
1am
54
52
South 3 mph - Drizzle, Fog
2am
54
52
SE 6 mph - Drizzle, Fog
3am
53
51
Calm - Fog
4am
53
51
NE 5 mph - Patchy Fog
5am
53
51
East 3 mph - Drizzle, Patchy Fog
6am
57
55
South 8 mph - Patchy Fog
7am
58
56
South 14 mph - Fog
8am
61
58
South 16, G 26 mph - Fog
9am
63
59
South 17, G 24 mph
10am
65
59
South 16 mph, G 24 mph
11am
67
60
South 13 mph
12pm
67
60
South 13 mph
1pm
68
60
South 15 mph
2pm
69
60
South 7 mph
3pm
71
49
West 14 mph
4pm
68
45
West 10 mph, G 21 mph
5pm
63
45
Variable 5 mph
6pm
51
44
SW 7 mph
7pm
57
44
SW 6 mph
8pm
47
41
Calm
9pm
56
40
NW 10 mph
10pm
53
32
West 7pm
11pm
49
30
NW 3 mph