One System Being Watched, but the Tropics are Unusually Quiet...

August 28, 2024

The National Hurricane Center is watching one area (technically two, but the other no concern) for development in the tropics. This area has a 20% chance of development over the next 7 days but I really don't think we're going to see much from it.

I think this is the first area of interest since Ernesto. This is, in a word, strange. We are less than two weeks from peak season and the tropics should be going bonkers right now. No complaints, it's not like anyone wants a bunch of storms. Models keep showing activity 7-10 out days and beyond, but each time as the time grows closer short term development disappears. We (meteorologists, I'm only loosely in that camp) keep thinking "here we go!" only to see it fall apart again and again.

The ITCZ (Intertropical Convergence Zone), the belt of storms in the tropics that produces stormy weather and tropical waves, has been displaced a bit more to the north over Africa than usual. It is producing very healthy waves but they are emerging off the coast into hostile conditions and then largely dissipating. It is so far north in fact that the Sahara Desert is about to get a bunch of rain (relative to normal). Dust plumes from the Sahara continue to be strong as well, helping stifle development.

I've mentioned it before, but tropical cyclones need a seed system to form from, they don't just pop up from warm water (and the water remains very warm). This time of year those seeds are typically tropical waves, but they are being planted in the poor soil of cooler water and dry air farther to the north instead of the fertile soil of warm water and moist air where they should be. I don't know enough to tell you why, but there are some other anomalous weather patterns (both atmospheric and oceanic) going on across the globe, perhaps they are connected.

I do think we need to keep an eye on close in development. As we get into fall and cold fronts start pushing through (unusually for August, we've had one or two recently) and leftover energy from these can be seeds for development as well. Both the northern Gulf and the Atlantic just off the East Coast can be hot spots. It may be that this will be the main type of activity we see this year if the deep tropics don't get their act together. As it is I think the forecasts calling for a hyperactive or above average season are likely a bust. I think we will see some storms, but the high numbers look to be overblown.

That's it for today. I said a lot, but really I just wanted to send out a "no news is good news" update since it has been a while.

Have a great Labor Day weekend.

Chris

Tropical Weather Update - Ernesto is not a Concern, Activity Still Expected to Increase Soon

August 13, 2024

The disturbance we were talking about last week is now Tropical Storm Ernesto and unless you're traveling relatively far away it is no concern. The current forecast is below. Ernesto is currently impacting the Leeward Islands and will bring some impacts to Puerto Rico before turning north. After that it will strengthen and may affect Bermuda, perhaps bringing significant impacts depending on the track, and maybe then the Canadian Maritimes later on. If you happen to be along the East Coast in a few days there could be a good swell from it so keep that in mind. 

Otherwise, the tropics are quiet, strangely so given the seasonal forecast and the time of year. It looked like the next two waves after Ernesto would need to be watched but if the models are correct there are virtually no signals for development over the next 7-10 days. Despite the non-existent signal in the models, the forecast for weeks 2 and 3 (August 21 - September 3rd) is for increased activity in the tropics. The expectation is for robust tropical wave activity to increase due to a more favorable background state. I think the models are missing the effect the background state change will have on tropical wave development, but once those waves form over East Africa the signals will return. This also aligns with climatology as we are quickly approaching the climatological peak of hurricane season, which occurs on average around September 10th. 

No concerns at all right now but with activity expected to increase soon there will likely be several systems to watch in the coming weeks.

That's it for today.

Chris

Another Chance of Development in the Tropics

August 9, 2024

Friday morning update on the tropics. The NHC is watching two systems in the Atlantic, the remnants of Debby which is finally exiting off to the northeast and a tropical wave that is about midway between Africa and the Lesser Antilles (orange 'X'). Debby is now post/extra-tropical but still poses some significant inland flooding risks. We now turn our attention to the deep tropics again.

The tropical wave mentioned above has a 60% chance of development over the next 7 days but it looks fairly certain that this system will develop by Wednesday or Thursday next week, if not a few days earlier. Unlike with Debby, there is good model consensus both for development and for the track. Right now it looks like any storm that develops would curve out to sea along the East Coast somewhere. I would say this is a medium to low confidence solution at this point because development is still several days away and because a few ensemble members do have tracks farther west (i.e. the Gulf). Also, the early solutions from the Euro with Debby had it going up the East Coast and that was not correct, although there is more model support from the GFS and Canadian models this time. I think we'll have a better idea early to mid week next week.

Despite Debby, the tropics are a bit slower than I expected them to be for mid-August. I may just be biased/jumping the gun from the expectation of an above average to hyperactive season, but this is typically when activity starts to ramp up. Earlier this week the NHC was watching a wave moving through the southern Caribbean for development but that didn't materialize. Also there are signals that the next few waves coming off of Africa will have to be watched as well, so maybe the switch is flipping on. Both CSU and NOAA issued updated seasonal forecasts recently. CSU dropped the total number of named storms by two, but left the number of hurricanes and major hurricanes unchanged. NOAA's forecast is more or less the same as it was. All the same, for those forecasts to verify we will need to start having very high levels of activity soon.

Here in the Southeast the weather looks to stay mostly warm and dry. A few coastal showers will be possible through early next week with maybe more widespread showers across the Southeast from midweek through Friday.

That's it for today, I'll probably send another update early next week.

Have a good weekend.

Chris

Update on TD 4 - Big Bend Landfall Late Sunday Most Likely

August 3, 2024

Taking a look at Tropical Depression Four this morning, the forecast has thankfully been consistent for a while now. Future Debby is expected to make landfall in the Big Bend region of Florida late Sunday or early Monday. The official forecast is for the storm to be nearing hurricane strength at landfall, but I think there is some room for that to increase a little bit as there is not much to inhibit strengthening other than its passage over Cuba and relatively fast transit over the Gulf.

Based on the way things looked a few days ago I honestly did not think we'd have a high confidence forecast this morning but thankfully we do. There were a few slight westward adjustments overnight due to the storm being located a bit to the south of the expected track, but I think that has settled out now. The storm has started its northerly turn and there is no reason to think that it will not continue to do so. Models are and have been in good agreement on a track towards the Big Bend for a while now. For what it's worth, the Canadian model is a bit more towards the west, over near Apalachicola, but I think it is an outlier. I will say that future Debby's future once it crosses Florida is much less certain, but as of right now I don't expect any further impacts to the Western Panhandle once it leaves the Gulf.

Barring any big changes, this will be my last update on this storm, but if you have any questions please ask. In a few days we will need to turn our attention again to the deep tropics. There is a robust tropical wave approaching the Windward Islands that is showing signals for development once it is in the Caribbean later this week. More to come.

Keep an eye on this storm just in case, but otherwise enjoy the weekend.

Chris

Update - Tropical System Expected in the Gulf Late Saturday or Sunday

August 1, 2024

The situation with the tropical wave the NHC has been watching has changed quickly. About the only thing of any confidence at this point is that it is very likely that there will be some sort of tropical system in the southeastern Gulf of Mexico late Saturday or early Sunday. Development chances are still at 60% over 7 days and 20% over 2 days, so development is not certain. Unfortunately the forecast for this system is very complex with many possible outcomes. It has been designated an Invest (97L), so an additional suite of models have started to produce data. I think recon flights will start soon as well which feeds better data into the models. However, until a low level center of circulation forms, possibly by Saturday, uncertainty will remain high and might continue to remain high for some time after that. No need to get too excited at this point but folks along the Florida Panhandle, especially from the eastern to central Panhandle, need to start thinking about plans and preparations. I'll summarize some scenarios below.

Models are more or less all over the place both from run to run and between each other. I could share them with you, but I think they're going to keep changing for a while so they're not the most helpful yet other than to see the wide range of possibilities. The Euro dropped its idea of a run up the East Coast more or less which is somewhat the cause of the excitement. The future steering environment is complex and there are too many unknowns that are causing wildly different outcomes. The storm will be approaching an environment with a high pressure to the west, another high to the east, and a trough or front in between. The relative strengths and positions of these relative to the storm and its strength are unknown and causing the high model variability as things change slightly from run to run or as different models evolve each in slightly different ways.

In the following, "storm" could mean anything from a messy depression or tropical storm to potentially a strong hurricane. Here are the possibilities, not in any order: 1) Storm landfall in the Big Bend / eastern Panhandle area, with the storm potentially moving off to the northeast if it finds an exit, possibly stalling a bit along the East Coast. This has some trending model support but is by no means a lock. 2) Storm stalls either before or after landfall in scenario "1" and meanders around over land or over the water, possibly for days. 3) If "2" happens and the storm either stays over the Gulf or returns to the Gulf, which are possible scenarios, some solutions have it going west (Texas is technically in play...) before making another landfall, possibly strengthening, possibly skirting the coast or maybe offshore a bit. Some solutions keep this storm somewhere along the northern Gulf for nearly a week before it finally finds an exit to the north-northeast. It could also stall or meander inland for several days. This third scenario, or a few different versions of it, is probably a worse case as it is possible that a much stronger storm could develop than is likely in scenario "1" and/or a stalled/meandering storm could dump rain over an area for many days.

Other than maybe a short term trend for the 1st scenario, it's not really possible to say which is more likely at this point. Maybe something will change and confidence in one general solution will improve but I'm not expecting that for a few days. The next update will be Saturday or sooner if warranted.

Chris