It is significant that the latest El Ni�o is forecast to slowly wane this year. This raises the likelihood that, as the summer wears on, the weather pattern for North America in general, and the U.S. in particular, will return to some semblance of normal. No one area of North America is expected to be stuck in an anomalous weather pattern for the entire season. Rather, summertime cool fronts should make regular passage across the northern and central tier states. Also, summertime high pressure areas are forecast to come and go over the southern tier of the states and a weak summer cool front or two is not out of the question. This should have a tendency to support slightly cooler than usual temperatures in and near the Upper Great Lakes region. Slightly hotter than normal temperatures are expected in the Tennessee Valley and the Middle Mississippi Valley, as well as out west from the Colorado Rockies to the Great Basin of Nevada. We expect precipitation anomalies to occur in two general areas. Somewhat more than the normal amount of rain is forecast for an area extending from Oklahoma to Illinois and eastward to Pennsylvania. Drier than normal conditions are forecast for an area from western Colorado and the Sierra Nevada Mountains. The southern tier states can expect near normal occurrences of rain events, whether the result of tropical weather systems or the seasonal monsoon. Since high pressure systems are not expected to sit in any one spot all season, no one area should be blocked from getting summer time rain systems throughout the warm half of the year. Any dry spells are expected to be limited and will likely be followed by a return to normal summer activity.

2003 Mid-Year Global Weather Outlook

World-wide effects of this year�s El Ni�o will wane as the sea surface temperatures in the equatorial Pacific Ocean return to near normal levels during the remainder of this year. Large portions of Australia have been having drought conditions for the past 2 years, though some relief arrived in February. As the El Ni�o event slowly weakens and dissipates, the rainfall activity in and around Australia should return to normal. There are likely to be fewer low pressure systems moving across the Mediterranean Sea. This means more summer time high pressure and more favorable conditions. Europe, western Russia and the Middle East could see a few unseasonably strong cold fronts into early summer and then a more normal pattern is expected to become established with more consistent weather in the subtropical latitudes of the Eastern Hemisphere. El Ni�o typically suppresses the development of tropical cyclones in the Western North Pacific (WNP) Ocean region. In past El Ni�o years, 24-28 tropical cyclones have been noted versus the normal 32. This year between 28 and 32 tropical cyclones are forecast for the WNP region. Above normal rains in tropical South America should ease off to near normal levels for the second half of the year. Wintertime precipitation is expected to be near normal across Chili, Argentina, southern Brazil and other nearby countries, with temperatures averaging near or slightly cooler than normal. A cool pattern with a mixture of dry and wet weather is forecast for South Africa, though the northern and eastern parts of South Africa will be warmer than usual at times. 

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