June 2003 Pennsylvania Experimental Forecast
At the beginning of each month, the State Climate Office will present a 30-day experimental temperature forecast for Pennsylvania. Each week it will be checked with actual data to test its accuracy.
For verification of the June 2003 forecast, visit the Verification Page.
May 2003 Conditions
The primary technique employed to produce the predictions below is an analog method. First, we compared the 500mb anomalies for the 29 days preceding May 29 (seen below) with previous May and June flow patterns using the NCEP reanalysis data set. We found that the May of 1979 and June of 1975, 1981, and 1999 were the most similar to this past May's geopotential height pattern.
The next 4 images show the 500mb heights and the 850mb temperatures for the 4 analog years we selected above.
Predictions
The following two images show the analog forecast for June 2003. The first image predicts how the average temperature for the summer of 2003 may compare to the average temperature for the summers from 1895 – 2000. The second image predicts how the precipitation amounts for the coming summer may compare to the long-term average amount.
These map products that predict the temperature and precipitation anomalies for June 2003 are a compilation of the weather conditions in the Junes that followed those years with similar Mays.
The temperature anomaly map predicts that this June will have below average temperatures in the Northwest and Texas, above average temperatures in the Southwest, South Florida, and Northeast, and around normal temperatures in the rest of the country.
The precipitation anomaly map predicts a wetter than average June in most of the Midwest, Great Plains, and Texas regions and drier than normal in California, the Rocky Mountains, and East Coast regions.
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:
