A quiet Atlantic persists but for how long? And more about the GFS scareicanes!

In brief: Today we explain why the Pacific should be more active than the Atlantic through the next 7 to 10 days and when that could theoretically change. We also talk more about the GFS model’s phantom storm bias.

We’ll keep this fairly brief today. The Atlantic is quiet, so I don’t want to go fishing for speculative information. Plenty of other sites do that. That said, we know people want to know how long the generally calm conditions will persist.

Pacific or Atlantic?

The atmosphere over the eastern Pacific and western Atlantic right now appears to be entering a phase that is indeed favorable for tropical development. If we look at what is called a “Hovmöller” plot, we can identify areas in the tropics that are favorable or unfavorable in terms of where rising air is located.

A Hovmöller diagram can indicate where rising air in the tropics is located. Currently and for the next 10 days, it will be over Central America or on either side. (ECMWF)

So over the next 10 days, we have an area of rising air, indicated by the blue/green colors above. This is actually showing what we call “divergence” in the upper atmosphere, which typically correlates to “convergence” in the lower atmosphere. For air to rise, you want converging winds. For tropical systems you want rising air. So that’s firmly in place near Central America for the next 10 days.

Here’s where the models have actually been somewhat useful. Recall, the GFS model has been going bonkers with a Gulf system almost every day this month and several days last month. But also notice how it’s never advancing in time. It’s always been on like days 10-15. More on that in a second. But if you look under the hood on the GFS and European models, you have also seen a decent signal for Pacific tropical activity.

Odds of tropical development in the Eastern Pacific are quite high over the next few days. (NOAA NHC)

When we look at European model guidance, we can clearly see this Eastern Pacific area that will move out into the Pacific. But we can also see perhaps 1 or 2 other areas by day 10 that may develop close to the Central American or Mexican coast.

The European ensemble shows a busy eastern Pacific but a mostly quiet Caribbean and Gulf. (Weathernerds.org)

Now, the focus is clearly on the Pacific here, but there are elements of interest on this model very close to the east coast of Mexico in the Bay of Campeche. In theory we could see something like that later next week, but the proximity to land would likely hinder its organization significantly.

So I think over the next 10 days, while that area of rising air is in place over Central America, the odds will heavily favor Pacific systems over Atlantic ones, though the odds of a Gulf or Caribbean system may begin to increase after the 12th or so. That said, there’s no reliable model guidance showing anything of real concern in the Atlantic over the next 10 to 12 days.

The GFS phantom menace

I’m not going to belabor the point about the GFS model, but no matter how often we say it, it still seems people get spooked by this model still showing storms in the Gulf. Again, that is virtually always incorrect. And by virtually always, I cannot recall a major June storm in the Gulf in the last 10 years but I can recall dozens of instances of GFS refrigerator material every single year. In fact, as some others have shown recently, this signal of phantom storms actually stands out in verification metrics.

All my X’s live in the Caribbean. (Florida State University)

On the image above, each X indicates a time where the GFS showed something developing last year and it never formed. The majority of the X’s on that map are in the Caribbean (and likely in the early and late season), exactly where the GFS has been showing all the hubbub so far this season. The real tell though is when the storm is perpetually stuck in the day 10 to 15 day purgatory and never advances forward in time. It’s a dead giveaway that this model is up to its old tricks again.

Some people may say the GFS model is useless then, but reality is more nuanced, of course. The model has made improvements in skill over the years, including handling some tropical systems after they’ve formed. But as a forecaster, it’s important to recognize the model bias when you see it, and that’s certainly what we’re seeing right now.

Wee chance of tropical development near the Southeast coast the next couple days

In brief: There is a very small chance that a weak tropical system could develop near the Florida or Georgia coasts over the next couple days. Any development would be on the lower end of the intensity scale, and the primary impact will be some heavy rainfall.

A very, very low chance of tropical development exists from a system off the Southeast coast the next couple days. (NOAA NHC)

Un-Sunshine State

A weak disturbance is crawling up and just offshore of Florida’s east coast. The odds of this thing actually developing as it comes north are pretty low. Currently the NHC holds the odds around 10 percent. No real model solutions suggest that this will formally organize. Perhaps there’s a slightly higher chance of development as it turns the corner past the Carolinas and heads out into the open Atlantic. Whatever the case, in terms of a formal tropical entity forming, the chances are very low.

That being said, there will be impacts from this system as it comes north, and it will primarily come in the form of rainfall. South Florida took on a good dose of rainfall yesterday.

Monday’s rainfall in Florida was on the order of 3 to 4 inches in Miami, with higher amounts in Big Cypress (NWS Miami)

A flood watch is in effect for Fort Lauderdale, Miami, the Everglades, and Naples today. While official rainfall forecasts are on the order of another 2 to 4 inches of rain, some model guidance does hint at maximum totals in isolated areas hitting upwards of 6 inches or even a bit more. That would be most likely to occur south of Alligator Alley, which is to say in a less populous part of South Florida. Additional rains are likely tomorrow.

2 to 4 inches of rain in South Florida, with locally higher amounts are likely the next day or two. Additional heavy rain will occur up the Peninsula as well. (Pivotal Weather)

The actual disturbance we’re tracking will be up near Jacksonville by tomorrow evening. As it comes northward, it will spread some locally heavy rain up the coast. You can see from the map above how anywhere from 1 to 3 inches of rain is plausible across central and northern Florida. Some sort of weak low will probably come ashore between Savannah and Charleston tomorrow night, bringing more locally heavy rain up the coast there as well. Since this is likely to just sort of track along the coast and move inland from there, the heaviest rains will remain offshore, but anywhere from 1 to 3 inches is possible along the coast from Jacksonville through Myrtle Beach.

About 1 to 3 inches will locally higher amounts will be possible along the coast from Jacksonville through Myrtle Beach. (Pivotal Weather)

From there, the disturbance will turn right and exit the Carolinas out to sea where it will make another attempt at low-end development.

Bottom line? Whether this is unnamed or gets tagged as something formal, the impacts will be the same with locally heavy rain and flash flooding possible on the coast of South Carolina, Georgia, and North Florida, as well as across South Florida.

Elsewhere

Meanwhile, the GFS model has Mariah Carey’s “Fantasy” on repeat. It continues to show a fantasy (read: phantom) storm in the 10-to-15-day portion of the model. It remains alone, as it often is this time of year. No other model support exists. So we will continue to disregard it as fantasy. Broadly, conditions become a tinge more favorable next week in the Caribbean or southern Gulf, but we don’t see any specific systems of note at this time.

First Monday of Atlantic hurricane season brings mostly calm conditions

In brief: No tropical development is expected in the Atlantic this week. Next week looks modestly more interesting, but there are no real serious signs of anything specific to be concerned with. We also talk about a potpourri of notes at the end.

Atlantic update for the week ahead

No tropical development is expected in the first full week of June. At this time, the Atlantic looks mostly under control. We continue to see standalone GFS operational model runs blow up tropical systems in the Gulf. As we noted on Saturday, this is frequent, common May and June bias of the GFS model and typically never verifies, certainly not as shown.

No tropical development is expected this week in the Atlantic. (NOAA NHC)

At least at this point there remains no ensemble agreement from the European model (or the GFS really) and no operational model agreement from the Euro, ICON, or AI modeling. So the GFS operational model, as it so often does this time of year, stands on its own with whatever it’s showing.

Looking ahead

Heading into next week, I do think things will look at least marginally more interesting, however I’m not sure that it’s going to end up on the Atlantic side of Mexico. Modeling seems to be hinting at some sort of gyre-ish pattern (not sure that it’s a true gyre though, so we’ll call it quasi-gyre lite) over Central America. When this happens, as it often does in June, we can start to generate sloppy storms in the Gulf or storms in the Pacific. Which side of the continent these storms form in is always a challenging question, depending on a lot of things.

The best ingredients next week may end up over Central America or in the Pacific rather than in the Caribbean or Gulf. (Tropical Tidbits)

This time around, my gut feeling is that it may be the Pacific that cashes in with activity, just given model signals and where the best upward motion in the atmosphere may locate itself. Of course, as noted, this is always a challenging problem, so it’s not like we’ll just ignore it and call it a day. It will bear some watching, but at this point, no reliable model guidance is latching onto significant, organized development risk in the Atlantic heading into next week. So we have no real concerns at this point.

Other notes

A couple miscellaneous items that I’ll bring to your attention today.

Colleague and friend Michael Lowry wrote a particularly poignant op-ed this weekend in the New York Time about the risk of the rampant cuts to NOAA and the National Weather Service. While the newly released budget from Friday shows a small increase in funding to the NWS proper, don’t be fooled. Parts of the agency that are critically important to grow our understanding, improve forecasting, and increase our knowledge of meteorology are being absolutely gutted in that budget proposal. And to this point, there has been no sign that anyone in this administration wants to seriously do anything to get the NWS staffed back up to adequate levels today. This is not political, it’s common sense.

On a more positive note, I wrote a piece that I may ultimately republish here next year. But it is about which Major League Baseball stadiums see the most frequent postponed games due to weather. A few locations truly stand out, with a couple interesting surprises thrown in.

Finally, Arizona and northern Mexico had quite the soaking yesterday as Alvin’s remnants were shoved northward.

Rain totals across southern Arizona ranged from a few hundredths to an inch or two. (NOAA)

Some of the rain totals were fairly impressive with a few spots seeing north of 1.5 inches. We even had a flash flood warning just northwest of Phoenix this morning. Showers today will expand to the northern part of Arizona, as well as portions of southern Utah and western Colorado. All mostly welcome rain to be sure, but as is always the case in the West, localized flooding can occur with relatively small rain totals.

Long-range forecast scareicane season has arrived for the eastern Gulf

In brief: With the GFS model showing its first real scareicane of the season, we take a look at the facts and discuss the real potential of tropical development in the second week of June. Verdict? You don’t need to get too worked up.

Hurricane season hasn’t even officially opened in the Atlantic yet, and we’ve already got foreboding headlines about the first possible threat. A colleague of mine pointed out a Newsweek article referencing an AccuWeather outlook that suggests tropical development is possible between June 6th and June 13th. Seek it out if you wish, I am not linking to it in here.

We’ve also seen the GFS model show some solutions for tropical development in the Gulf over the next 10-12 days or so. As you can see from the last 10 runs of the GFS model forecast for 00z Tuesday the 10th (evening of Monday the 9th), there is zero consistency on where this goes or how strong it will be.

The last 10 GFS operational model runs for 10 days from now showing some potential tropical development but zero consistency on placement or intensity. (Tropical Tidbits)

In fact, this is very, very normal behavior for the GFS operational model this time of year. Notoriously, the GFS tends to flex in May and early June with numerous threats, not to say it isn’t periodically correct! But in reality, this is what we refer to as a model bias. In other words, the model likes to frequently exaggerate threats this time of year.

So in this case, is there merit to the potential of tropical development in about 8 to 10 days in the northwest Caribbean or southern Gulf? Maybe but not significantly so at this time. The GFS ensemble is showing some support for a possible northwest Caribbean system. The European ensemble has little support for this. The other operational guidance that can see out past 7 days is generally benign, including the ICON (through 180 hours), the European AI model (AIFS), and the European operational model. No signal shows up on any of those for anything organized.

Several things can be simultaneously true:

1.) It is normal for tropical systems to develop in the western Caribbean and southern Gulf in June.
2.) The models do show some semblance of moisture and weak “spin” in the atmosphere in that region in about 6 to 8 days.
3.) The GFS model has been eager about development, but it has historically had a poor track record this time of year in this exact spot and situation.
4.) No other model support really exists for organized development at this time.
5.) You do not need to worry about tropical development at this time.

European model setup next Thursday night shows possible Pacific development but no sign of any real organized Atlantic development. (Tropical Tidbits)

Interestingly, when we deal with these sorts of scenarios, where Pacific development occurs not too far off the coast of southern Mexico, models can sometimes struggle to resolve exactly what or where the system develops. In the GFS’s case, it seems to be wrapping a secondary vorticity maximum (spin) around the east side of the broader circulation in the Pacific, which is what it homes in on to develop in the eastern Gulf. The GFS solution is unlikely to verify as shown. However, the overarching theme does seem to favor more unsettled weather in the Caribbean later next week. I’m not quite ready to say that there is a good chance of tropical development, merely perhaps a slight chance.

I want to remind folks that hurricane season is a six-month slog. It’s not a marathon; it’s an ultra-marathon. News organizations are going to jump on the first iteration of anything they see this season, as they usually do. Even if the reporting is tame and mostly accurate, as it is in this case, there is an implication in the headlines that a serious threat exists, and there is a tendency to bombard people with that. It can get exhausting. One of our goals is to give signal to the noise. Why do we think what we think? Being from Houston, we know firsthand how badly disasters can mess with you mentally when new threats emerge and how important word choice is ahead of storms. This is partially why we want to cover the rest of the Atlantic and U.S. as a source you can trust ahead of hurricanes or extreme weather. Hopefully this does just that for storm-weary Florida folks now.