 Don't let this week's bone-chilling temperatures fool you. After a very hot summer and warm autumn, temperatures are expected to be slightly above normal this winter, somewhat similar to the relatively mild winters Central Texas has experienced over the past few years. While the atmosphere and oceans are giving few clues about the upcoming season, a combination of long-term trend and historical data suggests generally mild and dry weather conditions for the upcoming winter. Calendar year 2005 has been warm one. After a mild winter, spring and summer were hot, with more than 20 days having temperatures at or above 100 degrees. And the month of September turned out to be the hottest September on record. This warm trend shows few signs of weakening as we head toward winter and is a big factor in the forecast for a relatively mild winter. Active hurricane season a clue
Note that in this year, the Pacific Ocean is giving few clues for the upcoming winter as water temperatures near the equator are near normal. As a result, the weather phenomena known as El Niño and La Niña will not be around. But one clue for this coming winter may come from, of all places, this year’s extremely active hurricane season. When the hurricane activity in tropical Atlantic becomes as extreme as it was this year, the oceanic conditions that caused the activity are likely to influence atmospheric weather patterns even into winter. Climate records indicate that in winters following very active hurricane seasons such as 1933, 1969 and 1995, the coldest temperatures generally develop across the eastern United States, while relatively mild temperatures develop across the central United States. If this hurricane season connection holds true, it is another strong clue for slightly above normal temperatures this winter. Keep in mind, this doesn’t mean there won’t be at least a couple of periods with really cold temperatures. However, overall readings should average above normal. Drier conditions, too
Rainfall is likely to be below normal through most of the winter as well. The drier than normal trend that has persisted most of the year is expected to continue through the winter. With little to influence from the Pacific Ocean, the current long-term dry trend is likely to show little change. Once again, a climate connection with previous active hurricane seasons provides a clue for this winter. Climate records indicate that in winters following active hurricane seasons, the jet stream typically stays northeast of Texas, keeping most storm systems away from the state. This typically keeps rainfall somewhat below normal. Although this winter is shaping up to be relatively mild and dry, Mother Nature always has a few surprises in store for Texas weather. A White Christmas two years in a row will be tough to accomplish, but 90-degree temperatures in February won’t surprise me. Bob Rose is the chief metereologist with the Lower Colorado River Authority. |
