Quick Update on 98L

No real changes from this morning. At least two reliable computer models continue to forecast the development of Invest 98L, even though it may run into some strong wind shear as it continues its westward movement across the Atlantic. If you look at my earlier post, there’s a graphic of how wind shear cuts off the tops of developing storms.

Heavy rain continues across the midsection of the country. Here’s the Memphis Weathercast.

-Dawn Brown

A New Invest In the Atlantic

Invest 98L (courtesy NOAA) Click to Enlarge

The National Hurricane Center’s hurricane models are trying to develop a tropical wave out in the Atlantic off the coast of Africa. It is currently called 98L. (You can always click on the image to make it larger.) I think it’s a good chance this system could develop into another tropical system based on warm sea surface temperatures and favorable wind shear where it’s currently located. However, as it continues its westward migration, it will run into a good bit of wind shear,

Wind Shear (Courtesy NOAA - Hurricane Research Division)

and that will cause problems for the developing storm. As I’ve mentioned in the past, global computer models have a tough time forecasting the strengthening of a storm, the track forecast is more reliable. And the track forecast has this system turning north in the middle of the Atlantic, if it does develop. With the current weather pattern,  upper level troughs spinning off the East Coast of the United States, these storms are being turned north before they can come close to the United States this year. Tomorrow, I’ll explain what an upper level trough is… and why it’s helped us out this year!

These troughs have also created a cool summer for a good section of the country.

Dr. Jeff Masters from Weather Underground, looked at the climate data from this past summer, and had some interesting information about our summer.

Here’s the script from his blog:

“A cool August and cool summer for the U.S.
For the contiguous U.S., the average August temperature was 0.6°F below average, making it the 30th coolest August in the 115-year record, according to the National Climatic Data Center. The U.S. as a whole was below normal for the summer period (June – August). A recurring upper level trough held the June – August temperatures down in the central states, where Michigan experienced its fifth coolest summer, Wisconsin, Minnesota, and South Dakota their seventh coolest each, Nebraska its eighth, and Iowa its ninth. In contrast, the temperatures in Florida averaged out to be fourth warmest, while Washington and Texas experienced their eighth and ninth warmest summers, respectively.

U.S. precipitation in August was below average, as the month ranked 28th driest in the 115-year record. Arizona had its fourth driest August, New Mexico its fifth, and it was the eighth driest August for Colorado, Utah and Texas. Arizona observed its third driest summer, while both South Carolina and Georgia had their sixth driest. It was the 8th wettest summer on record in the Northeast.

At the end of August, 13% of the contiguous United States was in moderate-to-exceptional drought. This is a drop from the 19% figure observed at the beginning of the year. These extreme drought regions were exclusively in South to Central Texas. However, significant drought relief occurred in this region the second week of September, when a large area of tropical moisture settled in over the region, bringing heavy rains. About 19 percent of the contiguous U.S. fell in the severely to extremely wet categories in August.”

The link for Dr. Jeff Masters Wunderground Blog is on the left side of my screen. I’m sure he’ll have something about Invest 98L later today.
I’ll talk to you tomorrow! -Dawn Brown