Probably to no one's surprise around here, after our fourth wettest August on record, we have already reached our normal yearly rainfall.
We average 50.14 inches a year, and we passed that mark sometime in the morning hours of Aug. 21, which was also our wettest day of the month. Measurable rain fell on 19 of the 31 days last month and there were only eight days when no rain fell. And, as one might expect, all the rain and clouds helped bring about a slightly cooler than normal month. So whatever rain falls from now to New Years Eve is bonus rain for 2020.
As a whole the summer was slightly wetter and cooler than average. So I give myself a B- for my summer forecast (good June and July, bad for August). Will we end up breaking our all-time wettest year set just two years ago in 2018? It is partly dependent on the rest of the tropical season, which has been very active so far and shows no signs of slowing down anytime soon. The African monsoon season has been very strong and the eastern and central Atlantic have potential storms lining up like jets waiting to land.
My weather source in West Africa told me that they have had a very strong system go through their area in the past two days (Saturday), and to watch this one particularly. As I am writing this, the National Hurricane Center gives it an 80 percent chance of development. So the tropical season seems to have lots of energy left. But, as we found out last month, it's a matter of if and where they affect the U.S.
While Laura smashed southwestern Louisiana with 140 mph winds and flooding late in the month, I doubt you even heard much about Nana and Omar, both of which went far away from our shores. Of great interest to those of us who watch the weather is the very strong front now poised to crash the heat wave in the Rocky Mountain states. Temperatures near 100 degrees in Denver as of this writing are forecast to drop into the 30s in a couple of days with snow. This will likely dig a trough into the central U.S. which is forecast by the long range models to reload at least once over the next two weeks.
What does this have to do with the tropics? A deep trough in the central states usually pumps up a ridge along the eastern seaboard, which often turns Atlantic tropical storms out into the Atlantic, keeping them away from the U.S. If this pattern can hold for the next two weeks or so, it might just turn all these African systems away from our area. But if the pattern weakens, then anywhere along the eastern seaboard could receive a direct hit.
If I lived in the Carolinas I would especially be on my guard. What we would have to watch for is anything developing in the Gulf of Mexico, since a central U.S. trough would likely steer it right up toward the Florida panhandle. The long-range outlook is for continued slightly cooler and wetter than normal through the next two weeks. With the now apparent reality of a developing La Nina in the Pacific (more on that in a later article), we will likely slowly transition to a drier and mild regime for Fall at some point. We may just have to weave and bob our way through another half-dozen or so tropical systems to do it.
Weather averages for August 2020: Avg. low: 69. Avg. high: 87. Lowest : 63. Highest: 93. Mean: 78.0 (-0.7). Rainfall: 8.46" (+4.46"). 2020 rain total to August 31: 52.67".
Mark Jenkins is Madison County’s cooperative weather observer.