April/May 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 April/May 2004 forecast, visit the Verification Page.

Predictions

The following products to guide in predicting the temperature and precipitation anomalies for April 2004 and May 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 March throughout the United States. Using these years (1945, 1925, 1918, 1910, 1907, 1911, 1967, 1985, 1963, 1938, 1921, 1905, 1968, 1935, and 1986) the composite temperature and precipitation trends of the months that followed were calculated. 

April 2004

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

The April temperature anomaly map predicts that it will be cool throughout the western half of the US.  Warmer than normal conditions are expected throughout the Northeast, and Southwestern Texas and Louisiana.  The Midwest should expect temperatures to stay near normal. 

The April precipitation anomaly map predicts a slightly wetter than normal month across south-central and north-central US.  However, the Ohio Valley and southern Florida should experience dry conditions.   

May 2004

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

The May temperature anomaly map predicts that most of the US, especially North Dakota and Minnesota, will experience slightly below normal temperatures.  Washington will be the only state to experience normal to slightly above normal temperatures.

The May precipitation anomaly map predicts slightly above normal rainfall across regions the Ohio Valley.  The rest of the US should experience near normal conditions.   

Pennsylvania 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 April and May 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 (solid line).