April 2003 Pennsylvania Experimental Forecast

At the beginning of each month, the State Climate Office will present a 30 day experimental temperature forecast for Pennsylvania and each week, it will be checked with actual data to test its accuracy.

For verification of the April 2003 forecast, visit the Verification Page.

The Current Forecast:

The primary technique employed to produce the predictions listed below in the line graphs were mainly analog methods. The first compared the 500mb anomalies for the 30 days preceding March 22 (seen below) with the previous March flow patterns using the NCEP reanalysis data set. The years 1948, 1950, 1954, 1955, 1964, 1974 and 1976 were most similar to this years pattern and have been chosen as our 7 analog years. When these were composted, the average April temperature and precipitation are seen in the second and third figures.

Using the 15 day medium range forecast temperature trends and the likely monthly departures based on the analog years, the following distribution of daily temperature departure from normal is expected for each third of Pennsylvania.