D.C.’s unusually warm start to November has quickly
become a distant memory following a particularly cold week. Yesterday’s high of 41° made for the coldest
day in the Nation’s Capital since March 28 (40°). Following another cold day today,
temperatures will start to moderate and reach the 50s by tomorrow. Highs for much of the upcoming Thanksgiving
holiday weekend will be near average in the mid-50s for the Nation’s Capital. That will feel balmy compared to the
January-like chill that’s enveloped so much of the eastern United States over
the last week.
These large fluctuations in temperature can be attributed to a shift in the
position of the jet stream. According to
the National Weather Service, jet streams are “…relatively narrow bands of
strong wind in the upper levels of the atmosphere. The winds blow from west to
east in jet streams, but the flow often shifts to the north and south. Jet
streams follow the boundaries between hot and cold air.” The major shift from warmer than average
weather when the jet stream was well north of the D.C. Metro Area changed to
cooler than average when a “dip” in the jet stream occurred that allowed the
colder than average weather to move south.
It’s been so cold in the Nation’s Capital that D.C.’s average monthly November temperature (combining daily high/low temperatures) went from being 10.8° above average for November 1 – 12, to being 3.4° above average as of November 20. A drop in monthly average temperature this great over the course of a week is dramatic and underscores how unusually warm the first 12 days of November were in Washington, D.C.
Given that NOAA’s temperature outlook is for near
average temperatures in the D.C. Metro Area for the rest of the month, November
2022 should finish as a warmer than average month. Some may wonder whether November weather
trends can foreshadow what the upcoming winter season will be like. There have been some winters when November’s
weather in the Nation’s Capital did, in fact, do that. Such was the case during the 1995-1996 winter
season. November 1995 was 6.5° colder
than average in Washington, D.C. with 0.5” of snow. As longtime Washingtonians may recall,
1995-1996 was D.C.’s third snowiest winter on record with 46” – roughly triple
the seasonal average of 15.4” at the time.
That winter was also 2.9° colder than average and featured a moderate
episode of La Nina.
On the other hand, November 2009 was 2.6° warmer than average in Washington,
D.C. and gave way to what became D.C.’s snowiest winter on record. A total of 56.1” of snow fell in the Nation’s
Capital during the 2009-2010 winter. The
2009 - 2010 winter was also 2.4° colder than average. However, unlike the 1995-1996 La Nina winter,
it featured one of the strongest El Nino’s on record. Thus, while November’s weather can sometimes
foreshadow what the upcoming winter season will be like, there are too many
variables to rely solely on November weather as a predictor.
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