Expected Temperature and Precipitation Departures from Normal for July and August 2004 by PA Climate Division

Temperatures recorded in Pennsylvania greatly exceeded normal values this past May, as it was the 5^th warmest May on record.  Using this anomaly as a basis, the PA Climate Office has produced a forecast of expected departures from normal for temperature and precipitation in July and August by climate division.  The PA Climate Office made predictions using the methodology below:

1)      Identify 10 warmest Mays (prior to 2004) on record.

2)      Obtain temperature and precipitation departures from normal in July and August for each of those years with warmest Mays.

3)      Calculate the average temperature departures from normal for all ten years.

4)       Calculate the precipitation departures from normal for all ten years.

5)      Results represent expected temperature and precipitation departures from normal for July and August.

Predictions for July:  The overall trend for PA suggests temperatures slightly above normal (.56 °F) with precipitation below normal (-.81 inches).  Climate Region 5 (Middle Susquehanna Valley) demonstrates the greatest temperature departure (+1 °F) with a precipitation departure of -.97 inches.  Climate Region 7 (Central Mountains) demonstrates the greatest precipitation departure of -1.39 inches, but a temperature departure of only .02 °F. 

Predictions for August:  The overall trend differs from July with temperatures significantly above normal (1.36 °F ) and precipitation remaining around normal.  Again, Climate Region 5 experiences the greatest temperature departure of 2.18 °F, more than double the expected departure in July.