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Early long-term forecasts indicate we may be in for another of our trademark Texas summers this year.
That is not much of a surprise, as most summers in Central Texas are hot and relatively dry. With the summer sun high in the sky, the jet stream moves north, taking most of the storms with it.
On occasion, a few storms from the Gulf of Mexico will interrupt the dry and hot conditions for a couple of days of cloudy, wet weather. Then it's back to more hot and dry weather. Summer high temperatures are generally in the 90s, with about 10 days of readings at or above 100 degrees. Rain is usually hard to come by between late June and the middle of August.
Early forecasts for the upcoming summer indicate that weather conditions will be fairly typical -lots of hot summer days with only a few days of rain.
Flux in Pacific waters
The reason? Waters in the tropical Pacific are in a state of flux between El Niño and La Niña. In late 2002 and early 2003, a phenomenon known as El Niño developed in the tropical Pacific.
An El Niño is characterized by the unusual warming of ocean waters between the west coast of South America and the International Date Line. El Niños typically bring our region wet and cool autumns and winters followed by dry and hot summers. On the other hand, a La Niña develops when these same waters turn unusually cool. La Niñas will often bring our region cold and dry winters along with hot and slightly wet summers.
Last year's El Niño faded during the spring as water temperatures cooled. In fact, water temperatures continued to cool over the summer and into fall. For a while, it appeared that the waters would become cool enough to produce a La Niña by late fall or winter. But by late fall, the cooling stopped and water temperatures actually began to warm.
Since then, the waters have remained slightly warmer than normal, and the latest long-range forecasts indicate that they will remain somewhere between unusually cool and unusually warm through summer. This "neutral" state should allow the development of typical summer weather across Central and South Texas.
High pressure dome will keep rain away
With little influence from the Pacific Ocean, a large dome of high pressure is expected to build over Texas in early summer and remain in this general location through August. This dome of high pressure will strengthen and expand to cover most of the western and central United States, keeping most of the storms away from Texas. As a result, we can expect a mostly dry weather pattern to develop in June and continue through August.
The large high-pressure system that develops over Texas will not only keep our weather dry, it will also cause periods of very hot temperatures. In fact, if the weather stays dry, it will be easier to produce some long streaks of hot temperatures.
As in most summers, the one big wild card in the weather will be the tropics. This year, hurricane forecasters are already seeing some factors in the oceans and atmosphere that indicate this may be another busy tropical weather season with an above-average number of storms.
It is certainly not out of the question that a storm or two could make landfall along the Texas coast, possibly bringing heavy rains into Central Texas. Keep in mind that tropical systems are often fickle, with some storms producing flooding rains while others are barely wet. With the forecast for a dry summer, tropical weather systems may be the only way our region sees rain this summer.
Bob Rose is LCRA's chief meteorologist. Got a weather-related question? Write him at bob.rose@lcra.org.
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