October / November 2003 Experimental Forecast for Pennsylvania
At the beginning of each month, the Pennsylvania State Climate Office will present an experimental temperature forecast for the Commonwealth. Each week it will be checked with actual data to test its accuracy.
For verification of the October and November 2003 forecast, visit the Verification Page.
September 2003 Conditions
The primary technique employed to produce the predictions below is an analog method. First, we compared the 500mb anomalies for the 26 days preceding September 26th (seen below) with previous September flow patterns using the NCEP reanalysis data set. We found that the September 1959, 1982, 1983, 1990, 1991, and 1992 were the most similar to this past September's geopotential height pattern.
The next 2 images show the temperature and precipitation anomalies in October when the data of those 6 similar September months are compiled.
The next 2 images show the temperature and precipitation anomalies in November when the data of those 6 similar September months are compiled.
Predictions
These following map products that predict the temperature and precipitation anomalies for October and November 2003 were formulated by finding the years that had Septembers the most similar to September 2003 and then comparing the temperature and precipitation trends of the October and Novembers that followed. These years were 1896, 1902, 1924, 1934, 1950, 1961, 1966, 1974, 1975, 1979, 1989, 1993, 1996, and 1999.
October
The following two images show the analog forecast for October 2003. The first image predicts how the average temperature for the month may compare to the average temperature for the Octobers of 1895 – 2000. The second image predicts how the precipitation amounts for the coming month may compare to the long-term average amount.
The October temperature anomaly map predicts that it will be cool in the East, especially, the Northeast and southern Alabama. Warmer than normal conditions are expected in the Central Plains, Rocky Mountains, and Northwest.
The October precipitation anomaly map predicts a drier than normal month throughout most of the country. Only along the Pacific coast, Pacific Northwest, Florida and southern Alabama, and along the Atlantic Ocean in New England are expected to be slightly wetter than normal.
November
The following two images show the analog forecast for November 2003. The first image predicts how the average temperature for the month may compare to the average temperature for the Novembers of 1895 – 2000. The second image predicts how the precipitation amounts for the month may compare to the long-term average amount.
The precipitation anomaly map predicts a wetter than average November along the Pacific Coast, in the Midwest, the Ohio Valley, and the Mississippi Valley. A drier than normal month is predicted in eastern New England along the Atlantic Ocean, Florida to central South Carolina, the Central Rocky Mountain area, and the Southwest.
The temperature anomaly map predicts that this November will have below average temperatures in the Northwest and North and Central Plains and above average temperatures in the South, southern Central Plains, and Northeast.
Pennsylvania Forecast
Using the 15-day medium range forecast temperature trends and the likely monthly departures based on the analog years, the following is a daily temperature forecast for October and November in Western, Central, and Eastern Pennsylvania. This forecast predicts the daily average temperature departure from the normal average temperature.
