Now we all know that models are nothing more than numerical predictions and they get less accurate the farther out we go. But there are some things we can look to when determining whether a given model output has any merit. For instance, when several of the major models have the same or similar outputs, you begin to wonder. It can also have to do with the actual model making the prediction. For the most part, the two top models in the world today are the European (ECMWF) and the United States GFS. Of the two, the ECMWF gets the nod much of the time today as it is the first four-D model. But the GFS is integrating the change to four-D and will be running head to head with the ECMWF in the near future. And the GFS does already have its moments, so I am not maligning it in any way. So what is all of this about? check out this image.
This is the ECMWF output for 1220 UTC on Thursday 17-September, about 7 AM next Thursday. It clearly shows a 1000 mb, 29.53 inHg, tropical system gaining strength in the southwestern Gulf and heading to the northwest. The given pressure levels would easily support a mid-sized tropical storm and with the model showing pressure falls of about four millibars per six hours it would be intensifying quite steadily. A heading of northwest would put the Louisiana coast line in the path of the system, whatever it becomes. The formation of the system is a logical one for this time of year. A cool front will approach the area around the 12th of the month and as normal stall out in the Gulf before falling apart. We often see Gulf originating tropical systems form on early fronts such as this.
But as we have noted above, one model does not a sound prediction make. But in this case, the GFS is also seeing a system. It is not yet got a handle on development speed, but that is not unusual this far out. A check of other global models, which do not forecast quite as far out as the previous two are also in support. Both the Canadian (CMC) and NAVGEM models are showing the initial formation of an area of low pressure in the northwestern Bay of Campeche about a week from today. This coincides with both the ECMWF and GFS model runs early initialization of the system.
Does this mean you need to start packing and hoarding bottled water and batteries? No! While the models discussed are quite good at what they do, they cannot predict a system with accuracy a week out. It could not form at all. Or it could form farther to the east, or west. It could move in a different direction. We just don;t know yet?? But if future model runs hold with the given scenario, I would guess we will have a tropical system trying to get it’s act to together in the southern Gulf early next week. If that happens we all need to keep a careful eye on the Gulf and be ready to protect life and property should the threat materialize. I’ll follow the future model runs and update as needed.
