Sunday, November 3, 2024

Initial Advisory for Potential Tropical Cyclone 18

November 3, 2024

The National Hurricane Center has started issuing advisories on Potential Tropical Cyclone 18. The system doesn't yet have the characteristic of a tropical depression, but given that it is expected to gain these soon and be near Jamaica when it does so, advisories have been started. The track forecast confidence is fairly high for the first few days but then lowers significantly by about midweek. This is a good time for a reminder that the forecast cone does not represent the uncertainty for any given storm, but is based on historical track error for the past 5 years so the real spread is probably a bit wider than shown. Regarding strength, the storm is expected to strengthen to hurricane strength but then weaken in the Gulf. Most likely, the main impact in the US from this system will be much needed rain and maybe some coastal effects if it retains tropical storm force winds by landfall. It may be a few days before we have a better idea of the final track. I posted a few model graphics for reference. The hurricane spaghetti models (first plot) look fairly clustered but you'll see quite a bit of spread in the ensembles (second plot) once the system gets to the middle of the Gulf.





That's it for this evening. Again, I really don't expect major impacts along the Gulf Coast but it'll be a few days before we have a better idea on the landfall location and forecast.

Chris

Friday, November 1, 2024

Tropical Development Possible in the Caribbean - Northern Gulf Impacts not Favored This Time of Year

November 1, 2024


TL;DR It's possible a tropical cyclone may develop in the Caribbean in a few days. While there are some model solutions you may have seen showing otherwise, and yes there is still some uncertainty, it is not expected that a tropical storm or hurricane will cross the Gulf this time of year and bring significant impacts to the northern Gulf Coast.


Getting to the full discussion, I hope everyone had a good Halloween. It's hard to believe that it is November. Also, the time changes this weekend and I am not ready for that. Anyhow, it is still hurricane season for the rest of this month and there is an area in the Caribbean we need to keep an eye on. After Milton there were two other named storms, Nadine and Oscar, but they were not a concern for the US. All the same the tropics are expected to be active at least through the middle of the month. That may sound unusual, but historically the first part of November sees about the same level of activity as the end of July. One key difference is that a lot of the storms this late in the season stay away from the US as I will explain in a moment.


First, let's take a look at the 7 Day Outlook. There are three areas being watched but the only thing we're concerned about is the red area in the Caribbean. There's nothing going on right now but over the next few days an area of low pressure is expected to develop which will probably further develop into a tropical cyclone. The NHC is currently forecasting a 70% chance of development through 7 days and a 30% chance through 3 days with the expectation that a tropical depression will form this weekend or early next week. Beyond that the future of this system is uncertain but I think it is fairly unlikely that we'll see major impacts along the northern Gulf if it heads this way.



Getting into the details, the NHC first highlighted this area for development last Saturday. I haven't mentioned it until now for a few reasons. One is that some of the model solutions were exhibiting biases, that is generating storms in a manner that doesn't make sense given what we know about development in this area this time of year. There also hasn't been a lot of consistency in timing or location of development. Originally the NHC was expecting development of a previous area of disturbed weather that has since dissipated. So this has been another case of kicking the can down the road. As of yesterday there was finally a strong and consistent enough of a signal to start paying more attention despite the fact that you may have seen scary looking posts on the internet for a week now.


So what happens if this does develop in a few days? As mentioned above, that is uncertain at this point but I'm not too concerned. There have been model solutions on and off that show a strong storm in the Gulf at some point with various tracks towards land but the strong solutions are in the minority. Also, it is fairly rare to have significant tropical impacts in the northern Gulf this late in the season. I know it hasn't been cool for the most part, but we are in the time of year when regular cold frontal passages create strong wind shear in the Gulf and especially the northern Gulf. So while conditions in the Caribbean are still able to produce tropical cyclones, they typically will not survive if they move north. The steering winds are also typically such that they get blown off to the northeast instead of being pulled to the north. I like pictures so I'm going to illustrate this with a few below. The first shows historical development locations and tracks for the first 10 days of November. You can see there's been plenty of development but only a few tracks north. The second image shows the number of named storms that have passed within 150 nautical miles of a location over a 100 year period for November. The entire Gulf Coast is in the less than 10 category. We could argue that due to a warming climate or whatever and the fact that it's only November 1st and not halfway through the month that we are really in a more "October-like" climate. Even then you'll see in the third image for October that the majority of storms avoid the northern Gulf and the same pattern we see in November showing development in the Caribbean with storms moving northeast is present. All this is to say that history is no guarantee of the future but when we see model solutions for the first week of November showing a strong storm in the Gulf we take it with a grain of salt unless there is a compelling reason to believe otherwise and currently we are not compelled. This is something we should watch but it is fairly unlikely we will see any impacts other than rain (which would be welcome) if it did move to the north and not somewhere else.






In other news I have been getting a lot of questions about when we will get rain and when it will cool down. The short answer is that I don't know. A front moved into the area yesterday but stalled just short of us. Still, there have been some showers the last few days and while this will continue through today and maybe tonight the accumulation amounts will not be significant. Another front will move through Tuesday, Wednesday, and Thursday and while precip chances will increase most of us will not see more than half an inch. Short of anything tropical, it looks like it may be pretty dry and warm probably through the end of the month. Maybe something will change and the pattern will break, but right now that looks to be well in the future. I know people that prefer cool weather aren't crazy about prolonged warmth, but the weather has been amazing, the dryness notwithstanding. Enjoy it if you can.


That's it for today. If it looks like the storm in the Caribbean may be a threat I'll let you know.


Have a good weekend.


Chris

Thursday, October 17, 2024

No Tropical Threats to the US Expected for the Foreseeable Future

October 17, 2024


Hi everyone, a quick update on the tropics. The National Hurricane Center is still watching the same two areas for development. However, neither of these are expected to be concerns for the US. The reason is that wind shear across the Gulf and in the Atlantic off the Southeast coast is very strong and forecast to remain that way throughout the life of these systems. You can see this is the second image. I missed seeing this when I sent my last update, I apologize for that. Steering level winds are in the same direction as the wind shear which would also make it difficult for a storm to approach the US. So no concerns here.



Not considering wind shear, the overall environment in the Caribbean is expected to stay supportive of tropical storm development for several more weeks. Due to this the Climate Prediction Center is forecasting a 20% chance of tropical development through the first week of November. It remains to be seen if the wind shear will die down enough for this to happen and if there is some sort of seed system available for s storm to form, but if so there may be one or two more systems to watch.


Other than that there's not a lot going on, the next significant chance of rain might not be until we get close to Halloween.


Have a good rest of the week and a good weekend.


Chris

Monday, October 14, 2024

Two Areas Being Watched in the Tropics

October 14, 2024

The tropics have quieted down a little since the recent active period, we have to go back to Saturday since we last had a named storm (Leslie). Currently there are two areas being watched for development as shown below.



First, another CAG-like system may form in the Caribbean towards the end of the week. Current chances of development are 20% through 7 days and 0% through 2 days. Satellite data indicates an area of thunderstorms is starting to loosely organize in the southwest Caribbean. Models have hinted at development in this area since before Milton made landfall. The GFS model has been the most aggressive but since it can have a bias towards false development in this area there has been uncertainty whether this would occur or not. There has been some ensemble support as well from the GFS, Euro, and Canadian models so this combined with the consistent GFS runs and recent satellite presentation has caused this area to finally show up on the 7-Day Outlook. Track options are all over the board so we'll have to wait a bit for a better feel for that.

The orange area is a tropical wave that tried to develop but just didn't make it. This area will continue to the west or west-northwest and and may make another run at development as it nears the Lesser Antilles and Greater Antilles later this week or through the weekend. Development chances are currently at 60% through 7 days and 10% through 2 days. No promises but I think this will get pulled to the north before it threatens the US, something to keep watching though.

Here in the Southeast it looks like the weather will remain dry for most of us through the weekend with the exception that folks in Eastern Tennessee may see a few showers tomorrow. We'll also see a few cooler days Wednesday through Friday with a few nights in the 30s in TN and North AL and some upper 40s all the way to the coast. Daytime highs will be very fall-like!

That's it for today, more info in a few days as we know more about this system in the Caribbean.

Chris

Sunday, October 6, 2024

Sunday Evening Update on Hurricane Milton

October 6, 2024

The situation has changed very quickly since my last update on Friday. Milton became a tropical depression on Saturday and a tropical storm soon thereafter. Currently, Milton is a strong category 1 hurricane with 85 mph winds. Milton is forecast to make landfall along the Florida Peninsula on Wednesday somewhere in the vicinity of Tampa, +/- 50 miles or either side. The storm is forecast to be a 145 mph category 4 hurricane 48 hours from now and the NHC warned this may still be a conservative estimate. Milton is forecast to weaken somewhat before landfall but just how much is uncertain. It is currently a small storm but as it weakens it may grow much larger, with the wind field expanding over a much larger area.



This is going to be a very bad situation for those along the West Coast of Florida and for a large part of the Peninsula. Those along the coast have barely started recovering from Helene and for some people it is about to get much worse.

This to me was a bit of a miss. We knew there could be another storm in the Gulf before Helene made landfall. Originally it looked like development would happen in the middle of the past week, but as that got closer those chances faded and moved out in the future. The update I wrote on Tuesday the 2nd did mention development was possible over the weekend but the strongest signal was for development around Tuesday or Wednesday. On top of that there weren't very many strong solutions early last week. Then this past Thursday and overnight into Friday everything changed, with every major model forecasting development. Less than 48 hours after the NHC had a 30% chance of development in the Gulf we had a named storm. The intensity has taken a lot of people by surprise as well. Even when development of Milton was imminent several forecasters I trust were only calling for a strong tropical storm or minimal hurricane at most, now we're looking at a category 4 or 5 storm in the Gulf in a few days. We've all seen that October storms can be very strong, so in that respect this is no surprise, but I don't think anybody was expecting this a few days ago.

This will be my last update on Milton, but please let me know if you have any questions. I do post more frequently on Twitter (X) and Facebook, so you're welcome to follow me there. Beyond Milton we may need to keep watching the Caribbean for development of maybe two more systems before the end of the month.

Have a good week.

Chris

Friday, October 4, 2024

Tropical Development Likely in the Gulf - Landfall Will Probably Be Along The FL Peninsula

October 4, 2024

Good news: it's Friday night. Bad news: I have to tell you that there may be another hurricane in the Gulf in a few days. Good news (for us in the Panhandle anyways...): it is probably going to hit the Peninsula. Now that that's out of the way...As recently as yesterday the spot in the Gulf was down to a 30% chance of development. Ever since midday yesterday all the models have quickly come on board with development of a tropical cyclone. The National Hurricane Center now has this area (recently labeled Invest 92L) at 70% through 7 days and 30% through 2 days. Development is more or less certain and landfall looks to be around Wednesday. It is too early to know what the intensity will be with solutions ranging from a tropical storm to strong hurricane depending on whether the storm is located in a favorable location relative to the trough providing the steering influence. The trough may shear the storm and inhibit development or it may help vent the storm (as we saw with Helene) and aid in strengthening.



When a few models first started jumping back on board with this system yesterday I initially didn't pay too much attention, I thought they were just flip-flopping as they have been the last week or more. But overnight, every major model started indicating development. In addition, satellite images are showing the beginnings of organization so these aren't just spurious model solutions. The really good news (as I said, for us in the Panhandle anyways) is that the majority of models have tracks that take this system towards the Florida Peninsula, I've shared a super ensemble image below. None of us need a storm, but some of those areas in the Peninsula are still recovering from Helene. As always at this stage of the game there is some uncertainty but the steering pattern seems to be well established. We need to keep a watchful eye on any system in the Gulf, but I don't think this storm will be a concern for the Panhandle.



That's it for tonight. I'll send out another update once the forecast consolidates better in a day or two, but I don't expect any big changes.

Have a good weekend.

Chris





Wednesday, October 2, 2024

Development Chances in the Tropics a Little Lower

October 2, 2024

Some good news. At least for the short term, development chances have decreased in the Gulf of Mexico and northwestern Caribbean (which I misspelled in my title in last update...). The NHC is now forecasting a 40% chance of development through 7 days, down from 50%. A few days ago it looked like we might see development start today or tomorrow and now that looks to be delayed until at least this weekend or next week, if at all. The situation is a bit complex, which is code for "we think something will probably happen but we don't know when or where." There is an area of disturbed weather in the Bay of Campeche that will expand to the north and increase rain chances along the coast through the weekend. This area may try to spin something up but that looks unlikely in the short term (3-5 days), or at the most it would be broad and disorganized. As we get into the weekend and early next week this area may have a better chance to consolidate or combine with energy from a front that will push south Monday through Wednesday. Overall the development signal is weak to moderate at the most (30-40% chance). Also, other than a few low probability solutions, there isn't a high likelihood of seeing a strong storm from this system.

I should have said it last time, but the other things out there are no concern for us. We'll need to watch the red 'X' to the southeast of Kirk for a few days, but I think it will likely recurve into the open Atlantic way before it gets close to us. Kirk is going to curve away for sure.



Outside of the tropics the weather will be mostly dry for maybe a week or more except near the coast as mentioned above. From now through the weekend expect temps to be at or a little above seasonal norms. Once the mostly dry cold front pushes through early next week we should all see a few days of below normal temps giving us our first taste of fall.

I'll keep you posted on the tropics if something changes. Have a good rest of the week and a good weekend.

Chris