I’ve been doing tropical weather updates for my friends and family for years. It occurred to me that I might as well post them over here. A quick intro: I’m an amateur weather geek, but I’ve been following this stuff since the 90s.
My friends and family depend on my updates because - while I’m not trained, I put together the best information from the best sources. And while television meteorologists have gotten better in recent years, there’s a LOT of hype out there, and a lack of information. People are surprised by things they shouldn’t be surprised by, and that upsets me.
I will always post my sources and the information I have learned from people smarter than me. So let’s get going!
PTC 18 currently is expected to gain tropical characteristics and become a tropical storm on Monday 4 Nov, so the NHC has started issuing advisories on the system.
This is the current NHC forecast track. It is important to remember that this represents where the CENTER of the system is currently predicted to be - somewhere within that space. While the center of the space is the best guess, anyone near the cone should keep an eye on the system, depending on the forecast strenth - we’ll get to that in a moment.
This is the current spaghetti - or as I refer to it, the “spag”. You can get that from here:
However, I use Mike’s Weather Page to get there:
https://www.spaghettimodels.com/
Mike has the best (imho) single source of graphics, although he gets a bit hype focused, so while I appreciate his enthusiasm, I mainly just get graphics from his collection (which themselves come from elsewhere). Not to disparage him, he’s a good guy and definitely an enthusiast.
What is the spag? It’s the latest run of a number of hurricane models. When the spag is tight, it means that the forecast track is more confident at that point. It can always change, and it will always shift a bit.
In this case, there are two things to notice:
First, the spag is tight for the next few days, meaning that it’s currently likely that we’ll see this system out in the Gulf to the west of Florida and north of Cuba.
Second, while some models show a Louisiana landfall, others don’t make it that far. This is because they’re forecasting different speeds for the system, and the models only go out a few days. That’s one reason to take the Louisiana landfall with a bit of salt for the moment. I’ll get to another shortly.
This is the SHIPS intensity forecast. It shows various hurricane models as they predict the strength of the system over time.
It’s genereally wise to discount the outliers and concentrate on the bulk of the models. I would say at this point that it is likely that this system will be a tropical storm or category 1 hurricane at its peak, and it will weaken in the Gulf before any US landfall.
This is the EURO model for Thursday around noon. Specifically, this is the 850mb Height + MSLP centers. What that translates to is windspeed aloft, not at ground level.
Green is tropical depression force wind. Yellow is tropical storm force wind. Red is gale force (50 knot sustained) wind. And purple - not shown here - is hurricane force wind.
The EURO is one of the two models I tend to concentrate on, as it seems to me that’s what the forecasters also do. The EURO and the GFS are the best models out there, although other models are useful in their own way.
The EURO currently takes the system to around here, then it heads west and stays in the Gulf as it dissipates, ending up here in another couple of days:
You can see that the winds have essentially died down and it has basically dissipated as a tropical system.
You can get to that model here:
ECMWF Model - Tropical Tidbits
And now here is the GFS model, around the same time as the first EURO I posted. Notice now that the GFS is forecasting a hurricane - that purple is hurricane force wind. It’s forecasting a track off the western coast of Florida, and a landfall in the panhandle as a tropical storm:
The difference in the location between the EURO and the GFS for the next few days doesn’t bother me. This is normal. The models make different predictions, and can have different starting positions and conditions entered into them that can affect those things.
But the difference after that is a bit more striking, and tells me there’s a bit of uncertainty in the forecast.
Because this is not likely to be a strong system, I wouldn’t put much worry into it. Certainly not yet.
And it can be safely ignored for a few days. I’d say around Wednewday to Thursday, as the system is likely to leave Cuba behind - the models should have a better picture of the forecast strength and track, and around then is where I’ll be looking to see for possible US landfall locations and intensity.
So I’ve put in extra information to welcome my new friends from Imgur, and the last thing for this post will be to post my three main sources that I open up first:
- The NHC website. I always read the Forecast Discussion (see screenshot above).
- Mike’s Weather Page. Always a great selection of graphics
ECMWF Model - Tropical Tidbits
- Tropical Tidbits. This is where the models live. That link goes to the 850mb winds, which I consider the most important, but I’ll cover more models and options later. Also notable - when Dr. Levi Cohen releases an update, he posts on https://tropicaltidbits.com/ itself (the homepage) - and I ALWAYS watch those. He explains everything in an accessible way. No hype, and in depth. It’s okay not to understand it all, he explains in a way that still helps, and I’ve learned so much from him. I recommend watching his videos for the best possible information.
I hope this helps! And as always, I’ll answer any of your questions that I can.
I’ve also posted this update to imgur here: https://imgur.com/gallery/ptc-18-expected-to-form-gulf-of-mexico-CKlGiXa