January 2004 / February 2004 Experimental Forecast for Pennsylvania

At the beginning of each month, the Pennsylvania State Climate Office presents an experimental temperature forecast for the Commonwealth.  Each week it will be checked with actual data to test its accuracy.

For verification of the January / February 2004 forecast, visit the Verification Page.

December 2003 Conditions

The primary technique employed to produce the predictions below is a mixture of analog methods. First,the 500 mb flow pattern of the previous month by graphing the departure from normal.

Next, we compared the 500mb anomalies in December 2003 with previous December flow patterns using the NCEP reanalysis data set. The following years were close matches for the geopotential height pattern (images below): 1952, 1954, 1962, 1969 and 1995.

Predictions

The following products to guide in predicting the temperature and precipitation anomalies for January 2004 and February 2004 applied a second analog approach. This method compared years in which regional surface temperature and precipitation deviations from normal were similar to those experienced this past December throughout the United States. Using these years (1896, 2002, 1957, 1962, 1930, 1965 and 1999) the composite temperature and precipitation trends of the Januarys that followed were calculated. 

January 2004

The following two images show the analog forecast for January 2004.  The first image predicts how the average temperature for the month may compare to the average temperature for the Januarys of 1895 – 2000.  The second image predicts how the precipitation amounts for the coming month may compare to the long-term average amount.

The January temperature anomaly map predicts that it will be cold throughout the Southeast third of the nation.  Warmer than normal conditions are expected across the country from Oklahoma to Wisconsin and westward.

The January precipitation anomaly map predicts a drier than normal month across much of the nation, except along the perimeter. Above normal rainfall is possible from southern Texas to the immediate Atlantic Seabaord. It may also be moist in the Pacific Nortwest.

Pennsylvania Forecast

Using 15-day medium range forecast temperature guidance and the likely monthly departures based on the analog years, the following is a daily temperature forecast for January and February in western, central and eastern Pennsylvania.  This forecast predicts the daily average temperature departure from the 30-year average temperature.