Warm high pressure will steadily build over the Eastern U.S. starting Monday. By Dec. 24, temperatures in the Mid-Atlantic and Northeast could be running 30 degrees above average for this time of year. A bit farther north in Montreal, temps could exceed 40 degrees above average.
In Washington, D.C., the forecast models have been in pretty good agreement that temperatures will at least exceed 65 degrees in the days leading up to Christmas. The European model has been forecasting a high in the low to mid-70s for all three D.C. area airports on Christmas Eve. The GFS has been wavering, but recently seems keen on a high of 70 degrees for Reagan National, and highs in the upper 60s for Dulles and BWI.
The record highs for the Washington, D.C., area on Christmas Eve are low-hanging fruit — if the current forecast plays out, these records will be toast.
National – 69 degrees (1933)
Dulles – 66 degrees (1982)
BWI – 65 degrees (1990)
Records for Christmas set the bar a bit higher, and it’s still uncertain whether temperatures will surpass the 70-degree mark next Friday. It all depends on the timing of a cold front that’s scheduled to pass through on Dec. 24 or 25. If the cold front is much later than models are predicting, Christmas day could turn out to be the warmest day of the week, in which case record would be in jeopardy on the 24th and the 25th.
National – 72 degrees (1964)
Dulles – 71 degrees (1964)
BWI – 72 degrees (1964)
Though the streak will likely be broken this weekend, average temperatures have been above normal every single day this month at National. We’ve had five days with highs of 65 or greater, and the record is eight in 1998 and 1982, which was also a strong El Nino year.
When it comes to freezes, D.C. has only seen one this season and it came in November. National should see one or two this weekend, but that still puts this December in the company of the lowest number of freezes in the month of December on record. December 2014 — also abnormally warm — set the target with just four freezes.
The warm days are adding up, and now this month is challenging the warmest December on record in Washington, D.C. Through Thursday, Washington, D.C.’s average temperature for the month was a remarkable 50.4 degrees. The record warmest December was 45.6 degrees, which was tied between 1889 and 1984. It’s arguable the December record of 45.6 degrees has been due to be broken. January and February, the coldest months of the year in D.C., have record temperatures that are warmer than December’s record.
Even with this weekend’s cool-down, this month will challenge that record thanks to the very warm head-start and the potentially extreme temperature rebound next week. So far, this December is 8.9 degrees above average, and ranks as the 3rd-warmest month to-date behind 1998 (51.1 degrees) and 2001 (51.8 degrees).
Temperature records at National and BWI go back to 1872, though both locations changed the site of the sensor once. Records at Dulles go back to 1963.
Up and down the East Coast, the days leading up to Christmas seem likely to challenge records.
Dec. 24 record high / NWS forecast / European model forecast
Richmond — 71 degrees (1988) / 73 / 72
Philadelphia — 64 degrees (1990) / 67 / 70
New York City — 63 degrees (1996) / 63 / 70
Boston — 61 degrees (1996) / 62 / 62
In the New York City area, 51 temperature records were broken from Dec. 10 to 15 — 23 record highs, and 28 record warm lows. In that same period, the average temperature in Central Park was 64.8 degrees, which the National Weather Service says most closely resembles the average high in mid-October.
New York City is also challenging its December record. Through Dec. 17, the average December temperature in Central Park was 52 degrees — 12.4 degrees above normal. Central Park’s warmest December on record was 44.1 degrees in 2001. Records at Central Park go back to 1869.
Through Friday, Boston has had 13 December days above 50 degrees, and their record is 16 days. “That’s the most since 2006, and there are plenty more 50F+ temps to come,” writes WBZ meteorologist Eric Fisher. “Our current forecast calls for at least 4 more through Christmas.”
Boston’s warmest December happened back in 2006, when the average temperature at Logan Airport was 41 degrees. So far this month the average temperature has been 46.8 degrees, almost 10 degrees above normal. Fisher estimates that given the strong warm pattern that’s expected to take shape over the next two weeks, Boston is bound to see this December fall in the top five warmest on record, and a “strong candidate” for the warmest.
Records in Boston go back to 1872.