National Discussion
An approach to making a prediction for temperatures and precipitation for December 2004 and January 2005 is to analyze the anomalies of both temperature and precipitation over the past November.
November 2004 Temperature Anomaly
November 2004 Precipitation Anomaly
Using the temperature and precipitation anomalies seen in the above images,
years that matched both the warm/cool spots and the wet/dry areas across the
United States were found by entering the regions into our anomaly finding database.
Then, the 500 mb flow patterns for November for years that matched above 50%
were compared to the current 500 mb flow pattern of November 2004. Combining
these two methods yielded 1998, 1978, 1976, 1960, 1952, 1939, 1931, 1922, 1909,
1908, 1904, 1903 and 1902 as the years that coincided well with this November.
After putting together a composite map of these years, several predictions can
be made for December 2004 and January 2005.
Anticipated Temperature Anomaly for December 2004 (Fig 3)
- Very cold temperatures are expected for most of the west and northeastern
sections of the U.S.
- Slightly warm temperatures for southeastern U.S. and parts of Arkansas, Nebraska,
Minnesota, and Montana
- Much of the mid-west is expected to have normal December temperatures
Figure 3 Dec Temp Anomaly Prediction
Anticipated Precipitation Anomaly for December 2004 (Fig 4)
- Most of the country is dry including northeastern, western, mid-west and
southeastern regions
- Very dry prediction for northeastern Oklahoma
- Wet through mid-eastern states, including Tennessee, Kentucky, and parts of
Louisiana, Arkansas, and Texas
- Very wet spots in North and South Dakota
Figure 4 Dec Precip Anomaly Prediction
Anticipated Temperature Anomaly for January 2005 (Fig 5)
- Very cold temperatures for the eastern half of the United States
- Warm to normal temperatures predicted for the west
Figure 5 Jan Temp Anomaly Prediction
Anticipated Precipitation Anomaly for January 2005 (Fig 6)
- More than average precipitation for the northeast and northern mid-west
- Very dry anomalies in Oklahoma, Kansas, and Missouri
- Dry in southern regions and also up through the Great Lakes region
Figure 6 Jan Precip Anomaly Prediction
As far as Pennsylvania goes, a very cold and dry December is expected. This
analysis predicts continued cold temperatures through January, but with a normal
to slightly above normal precipitation amount.
Pennsylvania Temperature Forecast
Using 15-day medium range forecast temperature guidance and the likely monthly departures based on analog years, the following is a daily temperature forecast for May and June 2004 for western, central and eastern Pennsylvania. This forecast predicts the daily average temperature departure from the 30-year average temperature (dotted line) and the five day running mean of the temperature departure (solid line).
