The following is an excerpt of research conducted by Jeffrey D. Schultz, Chief Climatologist at Weather 2000. This case study was originally compiled in 1995, and has been updated each year.
November average temperatures (departures from normal) for Washington, DC National Airport (DCA) are compared to Winter average temperatures (departures from normal). Climatological Winter is defined as December/January/February, normal is the 1971-2000 average, above normal is any positive anomaly, below normal is any negative anomaly, and exactly normal is no anomaly, ie 0.0 degrees.
| Season | November | Departure | DEC-FEB | Departure | |
|---|---|---|---|---|---|
| 1948-49 | 51.4 | 1.9 | 42.2 | 3.8 | |
| 1949-50 | 48.1 | -1.4 | 42.8 | 4.4 | |
| 1950-51 | 47.9 | -1.6 | 37.8 | -0.6 | |
| 1951-52 | 44.1 | -5.4 | 40.9 | 2.5 | |
| 1952-53 | 48.2 | -1.3 | 40.7 | 2.3 | |
| 1953-54 | 48.1 | -1.4 | 40.1 | 1.7 | |
| 1954-55 | 45.2 | -4.3 | 36.8 | -1.6 | |
| 1955-56 | 45.5 | -4.0 | 36.4 | -2.0 | |
| 1956-57 | 46.1 | -3.4 | 39.5 | 1.1 | |
| 1957-58 | 49.5 | 0.0 | 35.7 | -2.7 | |
| 1958-59 | 49.8 | 0.3 | 35.6 | -2.8 | |
| 1959-60 | 46.8 | -2.7 | 39.5 | 1.1 | |
| 1960-61 | 48.4 | -1.1 | 33.0 | -5.4 | |
| 1961-62 | 50.2 | 0.7 | 35.1 | -3.3 | |
| 1962-63 | 44.8 | -4.7 | 31.9 | -6.5 | |
| 1963-64 | 49.8 | 0.3 | 34.7 | -3.7 | |
| 1964-65 | 51.0 | 1.5 | 36.7 | -1.7 | |
| 1965-66 | 49.5 | 0.0 | 36.7 | -1.7 | |
| 1966-67 | 49.5 | 0.0 | 37.5 | -0.9 | |
| 1967-68 | 45.0 | -4.5 | 35.2 | -3.2 | |
| 1968-69 | 50.0 | 0.5 | 35.9 | -2.5 | |
| 1969-70 | 47.2 | -2.3 | 34.4 | -4.0 | |
| 1970-71 | 49.3 | -0.2 | 36.7 | -1.7 | |
| 1971-72 | 48.1 | -1.4 | 40.1 | 1.7 | |
| 1972-73 | 46.7 | -2.8 | 39.4 | 1.0 | |
| 1973-74 | 51.6 | 2.1 | 41.3 | 2.9 | |
| 1974-75 | 50.8 | 1.3 | 41.5 | 3.1 | |
| 1975-76 | 54.4 | 4.9 | 40.4 | 2.0 | |
| 1976-77 | 43.0 | -6.5 | 33.2 | -5.2 | |
| 1977-78 | 51.8 | 2.3 | 33.9 | -4.5 | |
| 1978-79 | 52.2 | 2.7 | 35.5 | -2.9 | |
| 1979-80 | 54.4 | 4.9 | 39.0 | 0.6 | |
| 1980-81 | 48.5 | -1.0 | 38.8 | 0.4 | |
| 1981-82 | 51.3 | 1.8 | 34.9 | -3.5 | |
| 1982-83 | 51.8 | 2.3 | 40.8 | 2.4 | |
| 1983-84 | 50.3 | 0.8 | 37.3 | -1.1 | |
| 1984-85 | 46.0 | -3.5 | 38.0 | -0.4 | |
| 1985-86 | 54.3 | 4.8 | 35.7 | -2.7 | |
| 1986-87 | 46.5 | -3.0 | 37.1 | -1.3 | |
| 1987-88 | 49.8 | 0.3 | 36.6 | -1.8 | |
| 1988-89 | 49.9 | 0.4 | 38.8 | 0.4 | |
| 1989-90 | 47.9 | -1.6 | 38.9 | 0.5 | |
| 1990-91 | 52.0 | 2.5 | 42.0 | 3.6 | |
| 1991-92 | 48.8 | -0.7 | 40.6 | 2.2 | |
| 1992-93 | 48.8 | -0.7 | 37.9 | -0.5 | |
| 1993-94 | 48.8 | -0.7 | 34.4 | -4.0 | |
| 1994-95 | 53.3 | 3.8 | 39.3 | 0.9 | |
| 1995-96 | 43.1 | -6.4 | 35.2 | -3.2 | |
| 1996-97 | 44.1 | -5.4 | 41.5 | 3.1 | |
| 1997-98 | 46.2 | -3.3 | 42.5 | 4.1 | |
| 1998-99 | 50.3 | 0.8 | 41.1 | 2.7 | |
| 1999-00 | 53.1 | 3.6 | 40.0 | 1.6 | |
| 2000-01 | 46.6 | -2.9 | 36.1 | -2.3 | |
| 2001-02 | 54.8 | 5.3 | 43.2 | 4.8 | |
| 2002-03 | 47.1 | -2.4 | 34.0 | -4.4 | |
| 2003-04 | 53.1 | 3.6 | 35.9 | -2.5 | |
| 2004-05 | 51.0 | 1.5 | 38.5 | 0.1 | |
| 2005-06 | 50.2 | 0.7 | 39.3 | 0.9 | |
| 2006-07 | 50.7 | 1.2 | 38.6 | 0.2 | |
| 2007-08 | 49.8 | 0.3 | 40.9 | 2.5 | |
| 2008-09 | 46.6 | -2.9 | 37.2 | -1.2 | |
| Condition | Number of Times | Percentage |
|---|---|---|
| A cold Nov is followed by a cold Winter | 17 | 27.9% |
| A warm Nov is followed by a warm Winter | 16 | 26.2% |
| A cold Nov is followed by a warm Winter | 13 | 21.3% |
| A warm Nov is followed by a cold Winter | 12 | 19.7% |
| A normal Nov is followed by a cold Winter | 3 | 4.9% |
Thus, in
the above analysis, we see that 54.1% of the time, an above normal Nov is followed by an above normal
winter and below normal Nov is followed by a below normal winter, while 41.0% of the time, above is followed by a below (and vice versa).
The following graph shows the departures from
normal for November and Winter average temperatures, plotted against each other. The numbers were sorted in ascending order of
November departures, to see if there was any type of grouping or correlation.
The correlation coefficient is 0.2216, which is not statistictly significant enough to use as a forecasting tool.
|
|