Idalia to Make Landfall in the Big Bend Area Wednesday Morning as a Major Hurricane

August 28, 2023

Tropical Storm Idalia has started its journey north and as of the 10 a.m. CDT advisory it is nearing hurricane strength. The storm will continue north for the next few hours and then will start making a gradual turn to the northeast. Wind shear is currently limiting intensification but that will subside soon and allow Idalia to strengthen more or less all the way until landfall somewhere in the Eastern Panhandle, Big Bend, or maybe the Tampa area Wednesday morning as a major hurricane (category 3, maybe stronger). As of this forecast no significant impacts are expected west of Apalachicola but that could change if we see a more northly track. This link from the NHC along with info from local meteorologist are your best source for expected impacts. If you want specific info for a given area just let me know and I'll get that to you.

 

Because of the storm's more easterly launching point it looks like locations west of Apalachicola are clear from a direct strike. Most of the model guidance has been locked into the Big Bend area for days with only a few ensemble members showing tracks west of north. While those kind of tracks are technically possible I haven't seen any indication in any of the recent discussions that the steering flow could take the storm west. So think of a straight north track as being the worse case to the west with a curve to the northeast or even the east being most likely. As late as yesterday morning the NHC mentioned that the track was still of low confidence but that was the last time I have read that kind of language.

As far as strength goes, rapid intensification of the storm is almost certain at this point. That means that we are likely to see a category 3 storm at landfall with category 4 strength a possibility. Devastating to catastrophic damage (more details at the link) from winds and storm surge will occur for those areas near and to the east of the storm center.

Unless there is a track shift to the west this will likely be my last update on this storm. With that said, I want to take a moment and discuss how the forecast evolved from a "max cat 1" on Friday and Saturday to where we are now. First, the original forecast had Idalia forming either right over or very near the Yucatan Peninsula. The expected land interaction was going to prohibit any organization and strengthening until the storm moved north-ish over open water. Instead TD 10 developed (sooner than expected I should add) over open water and then did a counterclockwise loop over water to where it is now. This has allowed it to strengthen and to have a launching point into the Gulf father south than expected. So now we have a fairly well organized storm (currently only limited by some northerly wind shear) that will track over very warm water for a longer distance. Also, it was thought that dry air and wind shear along the expected track of the storm would slow development. While some wind shear does look to impact the storm in the near term, dry air does not look to be much of a factor anymore and the upper level environment is poised to help exhaust (favorably vent, not tire) the storm and aid in intensification. As I have mentioned in the past it is these types of things that can cause a forecast to be highly uncertain until a low level center actually forms and that is where we are at now.

"I" named storms have been retired more than any other letter (somewhat by coincidence) and it looks like we may see another name retired after all is said an done. This is going to be a very impactful and life changing event for those in the storm's path.

Folks in the Panama City area should keep an eye on the track for the next day or so in case there are some shifts to the west (I would expect any to be slight). The rest of us farther west are safe I think, but personally I'm always a little nervous when there is a strong storm close to me until it has made landfall.

Chris

 

TD 10 Forms in the Caribbean - Landfall in the Northeastern Gulf Expected Tuesday or Wednesday

August 26, 2023

The NHC began advisories on Tropical Depression 10 at 4 p.m. CDT today. The forecast cone is below and you can see that the center of the cone has the storm making landfall in the Big Bend area of Florida as a category 1 hurricane late Tuesday or early Wednesday. The storm is expected to be almost stationary for the next day or so and to slowly strengthen before moving north and then northeast while continuing to strengthen. 

As a reminder, the forecast cone represents the possible location of the eye and is based on 2/3rd's of the historical forecast track errors falling within the cone. In other words, "the entire track of the tropical cyclone can be expected to remain within the cone roughly 60-70% of the time (source)." It is noteworthy that the cone does not represent the forecast uncertainty for any particular storm. In this particular situation I am not expecting a landfall outside of the cone, but since this is the first storm of the season I wanted to let you know that this is always possible.

Below are a couple of different ways of looking at the models for this storm. The first is a density plot of four different ensemble suites. Depending on what models are available when this is made it could represent over 100 different ensemble members. It provides a good idea of how much uncertainty there may be. This particular graphic is from this morning's runs which have since shifted a little to the east but the spread is still pretty wide nonetheless. I think there is a medium amount of confidence that a landfall somewhere near the Big Bend area is the right solution but I don't think we'll know for sure for a few more days. You can find these plots here.

This second graphic is the spaghetti models from around noon today, I'm sure you've all seen these before. They are a group of (mostly) track only models and you can see they are favoring the eastern to central Panhandle as well.

Finally, here is a plot showing the model intensity forecasts. The official forecast is calling for a category 1 storm but you can see there is quite a bit of spread in the solutions below. At this point in time the two green solutions above a cat 3 are outliers, but I think we need to pay attention to the cat 2 solutions as a real possibility. When I was first looking at this storm a few days ago it looked like there could be some wind shear or dry air present that could impede intensification. That doesn't look to be the case anymore so I think it is possible that we could see a storm stronger (just maybe quite a bit stronger) than what the official forecast is showing.

That's all I have for today. I'll keep you updated on major changes the best that I can, but the official forecast from the NHC along with local meteorologists are your best source of up to date info. Let me know if you need some links, etc. Tropical Tidbits on Youtube is always a great resource and I would expect to see a new video from him today or maybe tomorrow. Depending on what changes we see tomorrow I might wait until Monday for my next update.

People in the Panama City area definitely need to pay attention and start thinking about making preparations. If it comes your way there will not be much time, especially if it is a strong storm. Those of us a bit more to the west need to keep an eye on it and be prepared to take action. I think people in the Pensacola area are likely safe but don't let your guard down just yet.

Have a good rest of the weekend.

Chris

Tropical Development Possible in the Southern Gulf Next Week

August 24, 2023

Synopsis, there is a 50% chance of development in the Caribbean or southern Gulf early next week. Lots of forecast uncertainty exists, but a track to the north or northeast looks likely if a storm does develop.

The National Hurricane Center is watching an area in the Western Caribbean for tropical development. Models have been hinting at development here for over a week and just yesterday became more bullish. In the late spring and towards fall we sometimes see what is called a Central American Gyre (CAG) setup which can sometimes spit out an area of rotation that becomes a seed for tropical development. I'm not sure if that is the case here (it sort of doesn't matter), but the NHC is forecasting a 10% chance of development through 48 hours and a 50% chance through 7 days in the area where we see a CAG. This area showed up on the 7 Day Outlook yesterday evening and went from a 20% chance of developing to 50% in 12 hours. Based on that and what the models are showing, it is something we need to watch.

Development could happen as early as Sunday or Monday in the Western Caribbean or later into Tuesday in the southern Gulf with a potential storm probably tracking to the north or northeast. For the rest of this discussion take it with a grain of salt. The track and strength of a tropical cyclone is difficult to forecast before the system forms. Once a low level center forms and that data is being fed into the models they start producing much better solutions. Before that time the models are more or less guessing where and when the center will form (if it does) and that can make a big difference for the forecast beyond that. With that said, a track to the north-northeast across the Gulf with a landfall somewhere along the Florida Gulf coast looks to be the most likely solution. The solutions are sort of centered on the Big Bend area, but really anywhere from the Florida/Alabama line to Fort Myers is in play (maybe beyond that to the west and the east). Storm strength is fairly uncertain also. Right now I'm not seeing many solutions that are producing a really strong storm but that doesn't mean it isn't possible. The Gulf is plenty warm enough so given enough time and the right environmental conditions a strong storm is possible. That being said wind shear and some dry air may be a bit of an issue but models differ on this so it's hard to know what environment a potential storm may see. What is interesting is that between the ECMWF (Euro) and GFS (US) operational models the ECMWF is much more bullish on development while also forecasting what looks like a more harsh environment. For whatever reason the GFS isn't showing any development at all (as of this morning) even though the environment it forecasts is better. Both the ECMWF and GFS ensembles have similar solutions as the operational models with maybe the main difference being that the mean solution for the Euro ensembles shows a better environment than the operational Euro by itself. This is notable because within the model suites of each the operational model isn't producing an outlier solution which tends to increase confidence in that solution (other model solutions notwithstanding). It is also interesting that the GFS is so quiet on this, especially because it often has a bias where it develops storms where there shouldn't be one. For what it's worth the Canadian model (which can be too aggressive at times) has a similar solution as the ECMWF. We'll see if the Euro backs off on this in future runs or if the GFS picks up on it and starts showing stronger chances for development.

That's probably more info than you need at this point but I wanted to point out the forecast uncertainty and what I'm seeing. I do think it is more likely than not that we'll see a storm develop in the Gulf next week. That being said if nothing came of this it wouldn't be the first time this year when expected development didn't occur. I think we'll have a better picture of what the possibilities are this weekend.

Looking at the rest of the Atlantic there are no other concerns right now although the high level of overall activity is continuing. Franklin doesn't look to be a threat to the East Coast, but it may try to sneak in close to the Northeast US around midweek.

That's it for today. If you've been slacking (like me) on your hurricane kit this would be a good time to get some supplies.

Chris

The Tropics Are Very Busy But No Significant Threats to the Gulf or East Coast

August 20, 2023

Here's a quick update on the tropics this Sunday afternoon. There are five systems on the 7-Day Outlook at various stages of development. The good news is that other than Invest 91L in the Gulf that will bring some impacts to the Texas/Mexico border area later this week there are no other threats to the US (not in my email: I should have said that there are no significant threats to the Gulf or East Coast of the US, Hillary is bringing significant impacts to the Southwest). I've included some forecast cones for completeness.

Franklin's Forecast

Emily's Forecast

TD 6's Forecast

So again no big concerns despite all of the activity. The Southwest Caribbean may need to be watched towards next weekend but that is still fairly uncertain right now and may just be noise in the models.

Have a great week!

Chris

Tropics Starting to get Busy But No Concerns at the Moment

August 17, 2023

Below is the 7-Day Tropical Outlook from this afternoon. Even though the tropics look busy there are really no concerns right now. There are a couple of tropical waves out east that may develop but they are likely to curve to the northwest (or north) and miss the Gulf if not the US altogether. The yellow spot in the Gulf will get your attention but it is not a concern for those of us east of Louisiana. Basically a low pressure system may form in the Gulf early next week (30% chance) from the combination of the northern end of a tropical wave and upper level low moving across the Greater Antilles and Bahamas. As it moves fairly fast to the west a tropical system may try to spin up which would bring impacts to the Texas/Mexico border area around midweek with maybe some impacts (much needed rain) up the Texas coast towards Louisiana. We might see some rain in the Florida Panhandle as the system tracks to our south but this doesn't look very likely right now. 

Other than the above, computer models are sniffing out the possibility of additional activity a week or so from now but it's not anything we need to talk about yet. Expect warmer and drier than normal weather to continue through the end of the month. Into September it will still be warm but maybe not as much so and we should see normal or slightly above normal precipitation return.

The expectation from seasonal forecasts is still that we should see a ramp up in tropical activity later this month and on into September. It remains to be seen if this will pan out but above average activity continues to be the consensus (not unanimous though).

Have a great weekend.

Chris