Historic Warmth, Saturday January 6, 2007

Record breaking warmth would not typically warrant a mention here in a monthly summary. However, the warmth that occurred through the morning and early afternoon of Saturday, January 5 was exceptional and deserves some attention as the records that were broken were significant.

Records
Temperatures soared through the morning and early afternoon to a high of 71° at 1:14pm at Albany New York with 70° readings widespread throughout the mid and lower Hudson valley with mid to upper 60 degree readings elsewhere. The 71° temperature at Albany not only smashed the daily record high of 60° set back in 1929, but more importantly tied for both the highest maximum temperature on record at Albany in the month of January as well as during all of meteorological winter which is defined as the months of December, January, and February.

With January 6, 2007 included , the temperature has only reached or exceeded 70° three times in recorded history at Albany. The only other times this has occurred was on January 13, 1932 and December 29, 1984, when the temperature at Albany also climbed to 71°.

Set Up
A unique set of circumstances came together to allow for the spring like warmth to occur.

First, the air flowing into and over the region was not cooled, as it typically is in January, due to a snow pack on the ground, which generally covers much of if not the entire Northeast. The exceptionally mild season to date had precluded any significant snow, which meant no snow pack to cool any air masses entering the region.

Second, the air over the Northeast was already exceptionally mild, by January standards, in the days preceding the 6th, with daytime high temperatures from the 1st through the 3rd in the 40s, then into the 50s on the 4th and 5th. And temperatures remained and even climbed through the 50s right through the morning of the 6th due to strong southerly winds in advance of a cold frontal system that was producing a widespread rain.

Third and most importantly, a southwest downslope flow of air developed in the region prior to a cold frontal passage and after the passage of the rainfall, during the early to mid morning of the 6th. The air essentially flowed over the Catskills, sinking and compressing on its trek into the Hudson valley, a process called downsloping. Downsloping winds cause the air to warm and dry through compression. So the combined effects of warming and already very warm air mass due to downsloping along with a period of strong sunshine which developed due to the clouds breaking up as the air dried, and the lack of any snow on the ground anywhere in the Northeast, allowed the temperatures in the Hudson valley to spike to around 70° just prior to the cold frontal passage which occurred between 1pm and 2pm in the Capital Region.

Gusty winds along with scattered showers and only a slow drop in temperatures into the low 50s by evening occurred with the passage of the cold front.

An Interesting Note
Accompanying the unusually high temperatures was a period of unusually high dewpoint temperatures which ranged from the lower to middle 50s. Dewpoints in the 50s indicated an unusual amount of boundary layer moisture (humidity) for the time of the year which resulted in the 70° weather feeling quite balmy. Typically, when it does get warm during the cold season, the air remains very dry, which feels cooler. This is why a temperature of 65° in April feels much cooler than 65° does in June, when the humidity, or dewpoints, are generally higher.