Matt Lanza

One-sentence summary

The near-term is quite quiet, and while there are a couple things to watch beyond the weekend, there’s nothing of any serious concern at the moment.

Happening now: Really nice for August

Things are quiet, and they’re expected to remain so over the next 3 to 5 days, with no areas of any real concern, and nothing rogue on any modeling. If we look at satellite this morning there are at least a couple areas that stand out. Certainly the storms over Missouri are notable. There is storminess off the Southeast and Mid-Atlantic coast, a disturbance north of Hispaniola, and another tropical wave entering the Windward Islands.

None of these areas looks particularly menacing though from a tropical development sense, and we expect the next five days to be storm-free.

The medium range (days 6 to 10): Next candidate for development emerges off Africa

The next period should start with a tropical wave in the Bahamas that will likely scoot toward Florida and the Gulf around day 6 (next Monday or Tuesday). A rather aggressive shot of dry air dropping south into the Southeast should act to really inhibit any development of that wave.

My guess is that tropical wave will either be dragged northwest into the coast in between the Bermuda high and the Texas heat dome, or it will get shunted off to the south and west toward Mexico. Or it may just end up getting dismantled. Regardless, no development is expected.

Behind that wave, we should see another one moving into the Antilles without much organization. Behind that wave another one should be emerging off Africa this weekend, and we’ll see where we are at the end of the medium-range period. The Euro ensemble (50+ runs of the same model with various tweaks), as it has been much of summer with main development region (MDR) waves is rather aggressive in developing this as it comes across the Atlantic, reaching about half to two-thirds of the way across by day ten. The operational Euro is emblematic of this, and you can see that on its day 9 forecast it shows modest development just east of the Lesser Antilles. This map shows what we call vorticity at 700 mb, about 10,000 feet up in the atmosphere. Vorticity can tell us where atmospheric disturbances are or how “robust” they are. You’ll periodically hear this referred to as “energy in the upper atmosphere” by some meteorologists.

Anyway, this shows that on day 9 there is one wave gradually approaching the Caribbean islands and another emerging off Africa.

The Bermuda high is expected to weaken a good deal by days 8 to 10 or so, which might imply the escape hatch out to sea will be open. Still, it’s 10 days out so we have a world of time to watch this evolve, should it even develop at all. As noted, the Euro has had an aggressive history this summer in the MDR, and it has not exactly worked out, so I’m not as confident as that particular model is in development.

Fantasyland (beyond day 10): No signs of anything specific for now

The good news about the fringe forecast period is that there is no real sign of anything specific showing up in modeling that we can point to and say “we might need to watch this.” Maybe, maybe that next wave off Africa has a chance to be the next one to watch. Maybe. You choose your words carefully this time of year, so we’ll keep watching.

One-sentence summary

While we continue to keep an eye on a couple robust looking tropical waves in the Atlantic, there has been no added support or reason to believe these are any likelier to develop this week than it appeared last week, which is to say chances are low.

Happening now: Do the wave

Looking at satellite this morning, we have two pretty distinct features in the Atlantic. If you did not know better, these might look somewhat likely to develop.

But you read our site each day, so you do know better! And what I can tell you about things today is that these remain just some relatively bulked up tropical waves. No development of these waves is expected over the next 5 days as they continue marching to the west. The leading wave should arrive in the Antilles by Wednesday, bringing bulked up rain chances with scattered showers and thunderstorms to many of the islands. The trailing wave may or may not make it to the Caribbean.

Wind shear is going to remain rather hostile across many key points across the basin, including in the Caribbean, Gulf, and southwest Atlantic.

This should act to keep any development chances of these waves very much in check over the coming days.

The medium range (days 6 to 10): Development odds remain somewhat squelched

There are a couple things to watch in the medium range but none that I think are particularly likely to develop. First, the wave entering the Caribbean early in the period that will struggle may have some potential to try and organize itself as it comes west if it can escape some of that shear above. But honestly, that’s entirely based on history. Because the models are not having it. Here’s a map that roughly shows how much uncertainty there is in the Euro ensemble (50+ runs of the same model with tweaks) forecast of sea level pressure with this wave as it moves toward the northwest Caribbean and Gulf.

There’s not much there. If there were higher uncertainty (in this case, a meaningful cluster of individual ensemble members showing development), these colors would pop more. To me, this indicates that within the ensemble spread of the 51 members from the Euro, there is not a ton of volatility. If a tropical system were likely, you’d expect volatility here. Since we don’t see this, it’s indicative that modeling senses a hostile environment toward any tropical development. So, yes, keep an eye on it, but odds seem to favor nothing over anything else.

There may be an additional wave off Africa to look at or perhaps the trailing wave in the Atlantic in the near term can try something, but all of these features are likely to have some headwinds inhibiting their organization.

Fantasyland (beyond day 10): I guess we can keep an eye on the Atlantic?

Trends this season have been very, very clear cut in modeling. A system shows itself as possible around days 10 to 13 or so, it holds in the modeling, a development area gets highlighted, and then it finds a way to fail. Now that we’re pushing through mid-August and toward late August, I don’t want to get lulled to sleep. But admittedly, I can’t help but wonder if we’re trending toward that potential again. There are some signs of a wave forming in the Atlantic in the 11 to 15 day period, but exactly how and where are up for debate within models.

So for now, we’ll say that development odds in the “fantasyland” portion of the forecast are maybe a little higher than in the medium or near-term, but I would not classify the odds as “high” by any means yet. That is good news in mid-August.

One-sentence summary

While there are a few things to keep tabs on heading into later next week, there is nothing currently expected to develop over the next three to five days.

Happening now: Central & Eastern Atlantic popping off

One look at satellite over the Atlantic, and you’ll probably ask how many storms we may see develop over the next few days. The answer is probably none.

Yes, we have several beefy looking tropical waves out there, but the combination of shear and dry air will probably inhibit these waves from developing. That doesn’t mean they can’t develop. Stranger things have happened, but over the next five days or so, there is evidence enough to believe they will not develop. So let’s enjoy a quiet August weekend in the tropics!

The medium range (days 6 to 10): What will that wave do?

Where things get a bit more interesting is the medium range. What will these waves do? As they comes west, they’ll eventually run into the Caribbean. From there there are some options. We could see something go into the Caribbean, in which case it may struggle due to wind shear. It could go across the islands, in which case it may struggle due to land interaction. Less likely but possible, it could track just north of the islands, which, who knows. Either way, none of these scenarios is likely to lead to a significant storm developing at this point. But, if it can maintain coherence through the period, then maybe it threatens to develop in the “fantasyland” portion of the forecast.

Just to emphasize what we’re talking about, here is the GFS model forecast on day 9, which show three distinctive areas of possible development, ranging from the Gulf to the southwest Atlantic. None of these are likely to develop by this point, but they are worth watching.

Any of these is a development candidate beyond day 10. Maybe.

Fantasyland (beyond day 10): Behind this wave is _____?

The bulk of our fantasyland period will be dictated by the wave in the medium range as noted above. Aside from that, it actually looks kind of quiet beyond day 10, which is somewhat surprising. There seems to be a fair bit of wind shear and dry air still holding court across the Atlantic, which may keep further development in check. The best “forcing” for tropical development may remain in the Pacific, which is actually pretty standard for El Niño. We will see how it all shakes out in the days ahead.

One-sentence summary

No tropical development is expected over the next few days, but there is some chance that a tropical wave coming west across the Atlantic will make an attempt heading through next week.

Happening now: All noise, no substance for now

Looking out over the Atlantic’s main development region (MDR) this morning, there is definitely some thunderstorm action but there is nothing near organization.

I’m not sure that I would assign a zero percent chance to this developing, but over the next 2 to 4 days or so, there is surely nothing imminent from the slop out there. Either way, look for storms to gradually work west or west-northwest across the Atlantic basin.

The medium range (days 6 to 10): Same story, same places

As we watch the Atlantic’s MDR over the next several days with these emergent waves, I don’t think the medium range will offer a whole heck of a lot different: Keep watching the MDR. There are no signs right now of anything close to home, and the north Atlantic looks quiet at this point. So we’ll keep watching between the Cabo Verde Islands and the Caribbean. If anything were to really get going from this stuff, it would probably wait until it got closer to the islands or the Americas.

Let’s briefly talk about what is expected out around day 7 or so. If we look at the forecast upper level map from the European ensemble mean (an average of about 50 different European model runs), we can see two areas of high pressure. One is over Texas and Mexico; another is over the Atlantic, southeast of Bermuda.

What this setup should do is take the tropical wave, assuming it doesn’t develop, and steer it west toward the Caribbean islands. So I would anticipate some better rain chances in that region by midweek next week. Beyond that, the pattern should allow for the wave to continue west toward the Gulf, unlikely to develop still by late in the period.

Fantasyland (beyond day 10): Nothing coherent, but stay tuned

If you believe the GFS operational model, the wave discussed above will develop at some point in the Gulf. I’m skeptical that will happen, surely as shown by the GFS, but given this is 10 days or more out there’s enough reason to keep watching the progress of this wave.

Overall, there is certainly more persistent “noise” in the extended forecast right now, but beyond monitoring that one wave, there is little else specific for us to really latch onto. So the moral of the story at this point is to just keep watching. We’ll almost certainly have something to talk about before the end of the month.