In the Southeast you’ve enjoyed a wonderful warm, sunny and dry week here. But to our west, our neighbors in east Texas, Louisiana, Arkansas and Mississippi have been inundated with heavy rain which is locked in place by the combination of a cut-off low pressure area to their southwest and a strong high pressure area here. The resulting wind flow is bringing up very moist tropical air from as far away as the Yucutan peninsula. You can see it well in the 850 mb flow coming up from the south on https://earth.nullschool.net/.
The wind flow carrying all the moisture is called an “atmospheric river” by meteorologists, and they are most commonly seen in California, where they are called the “Pineapple Express” because the moisture there comes from near Hawaii. In the Southeast, they are sometimes called the “Maya Express” because of the flow from the Yucutan, where the Maya lived. You can read more about it at Forbes.com here.
