After one and possibly THE hottest summers in US history, several of you are probably hoping for a change for this Fall and possibly Winter, too, I know I am. I have been working for the last several days to put together my Fall 2012 (August-October) and preliminary winter 2012/2013 (November-February) outlooks. Today, I am ready to release the 2012 Fall Outlook and will follow up within a day or so with the Preliminary Winter Outlook.
Beginning last autumn, the tropical waters of the Pacific cooled to the level in which a La Nina was present. The La Nina conditions existed throughout the Winter of 2011-2012 and continued into the Spring of 2012. Since late Spring and through this Summer, conditions have warmed and have been categorized as Neutral. Warming conditions are expected to continue through the next several months and continue right on through both this Fall and upcoming Winter seasons. In fact, conditions are expected to warm enough to be classified an El Nino. The El Nino conditions will play a bit of a role this Fall but will become a "major" player for this Winter. I will discuss this further in the winter outlook discussion.
For this Fall, I expect very little change to the overall weather pattern. Unfortunately, that means more drought and heat conditions across the center of the nation. This will likely lead to an expansion of the aerial coverage of the extreme and exceptional drought conditions. Much of the Mid-Mississippi Valley is already experiencing extreme drought with some exceptional drought experienced in spots. By the end of Fall much of Missouri and Illinois could be increased from extreme drought to exceptional.
Some drought relief is possible for portions of the Southeast and Southwest ; however, as I anticipated precipitation to be slightly above normal in these locations.
The general weather pattern won't be changing much month so more heat to the locations that has seen it all summer long. A bit of cool down, finally, will try to set in from the Ohio River northward encompassing much of the northeastern quarter of the U.S. in September. This is expected as a result of a pattern change developing to allow a trough to redevelope over the northern and northeastern U.S. The heat will be squashed into the Southern Plains and Rockies. By October, the expansive coverage of above and much above temperatures is expected to take hold again. In comparison to normal, October is forecast to be the warmest of the three months (August, September, October) of this outlook.
Regarding the Tropics
The tropics have been very quiet this season, overall. However, we did get off to a quick start with Tropical Storms Alberto and Beryl in May an d Hurricane Chris and Tropical Storm Debby in June. But there were no tropical cyclones in July and August likely won't see much of an increase. There is a disturbance across the eastern Atlantic. This disturbance may form into the next tropical storm of the season over the next 3-5 days. Overall, I only expect 5 more tropical systems this season with 2 forecast for August, 2 for September and 1 for October. While that will only yield 9 total storms for the season it is likely that one will still reach "Major" hurricane status of category 3 or higher based on conditions and analog year comparisons. The area of the Atlantic coast that would have the highest potential of seeing landfall of additional tropical systems this year would be from the mouth of the Mississippi River to the South Carolina coast.