While we have not yet reached June 1 and the official start of the 2018 Atlantic Hurricane Season, it looks like nature may be poised to jump the gun by a few days. Models have been hinting for about a week that something might try to form near the Yucatan Peninsula and move into the Gulf of Mexico late this week into the Memorial Day Weekend. The most consistent indicator of a developing system has been the European Model, which also happens to be arguably the best model for tropical systems. The US based GFS model has also hinted at a developing system but had a tougher job nailing down what it might do. Things have become a bit clearer over the weekend though as we now have several models pointing to development in the central to eastern Gulf by mid- to late week and some sort of system moving inland over the Memorial Day weekend.
The European ECMWF Model is still the most solid, showing a 996 mb system with winds near 40 knots approaching the Louisiana coast mid-weekend. There are a couple items of interest in this image of the 0000 UTC run of the Euro. The familiar bulls-eye of a surface low centered just about due south of Atchafalaya Bay is pretty obvious. But note the rain pattern. The heaviest rains early Sunday morning would be from the mouth of the Mississippi River to the north shore of Lake Pontchartrain, as well as over much of Florida. This is due to the fact that the system will likely not become very organized until it nears the coast, where waters are much warmer. Until then it is just a disorganized low with lots of rain mostly on the east side and with much less to the west.
If we move ahead with the Euro, we see that early Monday morning, the system is a little better organized, even with its proximity to land, showing a more concentric pattern, lower pressure of 994 mb, and winds over 40 knots. By early Tuesday morning, the system is now near Lake Charles with a central pressure of 993 mb and winds still near 40 knots. It is only on Tuesday, image to left, that the rain from the system separates from the moisture plume over Florida. It is this quirk, a sort of double system which seems to be giving the GFS problems. However, as of this morning, the Canadian “CFS” and the US Navy “NAVGEM” models. are both showing a similar system, though those models lie a bit east of the Euro, from the mouth of the Mississippi to the Mississippi Gulf Coast. But all then move it westward along the coast through early next week.
So what does all this mean? Keep a close eye on the weather as the week progresses and you make plans for the weekend, especially Sunday. It is still way to early to know if or where a system may form. Regardless, there is a strong likelihood that the Northern Gulf Coast and Florida will very likely get some rain and wind for the second half of the Memorial Day Weekend into early next week. As the system is projected to be a slow mover to the west, there will likely be heavy rainfall in certain areas, along with gusty winds and heavy thunderstorms in the impacted parts of the coastline. As with most early season systems, it is the rainfall which is likely to be the biggest problem. Also, expect these landfall projections to change as the week progresses. Everywhere, from Key West to the coastal bend of Texas could see some impacts from whatever forms. For the moment we are sort of in the center of things is about all we can say for now.
Finally, the way this system is projected to develop: that being a disorganized system which gets stronger as it approaches the coast is also what most of the major hurricane prognosticators are projecting for this hurricane season. We will likely see fewer storms form way out in the Atlantic and track for days across the ocean. This is due to cooler waters in the eastern and central Atlantic. However, waters in the Gulf, northwestern Caribbean and along the Atlantic seaboard are projected to be warmer than normal. So we may see more homegrown systems in the Gulf, NW Caribbean and western Atlantic. That may keep overall numbers down, but mean more system which do form impact the US. Time will tell? For now all eyes to the Gulf this week as we see what plays out. I will update mid-week or sooner as conditions warrant.