Matt Lanza

Despite some gnarly weather model runs, the situation in the Gulf of Mexico looks more wet than whirly

Headlines

  • Flood watches now in Florida with 5 to 15 inches of additional rain on the way to the south through Saturday.
  • Some slightly potential that a disturbance can form into an organized system as it moves out into the open Atlantic.
  • Moisture shifts into the central and western Gulf next week with locally heavy rain possible.
  • Continuing to watch the western Gulf next week for potential development next week, but recent GFS “scareicane” runs are likely illegitimate.

Florida focus

The main near-term concern remains the rain in Florida. A flood watch is now posted for South Florida through at least tomorrow evening.

Flood watches are now in effect for South Florida through Wednesday night, including Naples, Miami, Fort Lauderdale, and West Palm. (NWS Miami)

Mostly minor amounts fell yesterday, with the heaviest right near Titusville to the east of Orlando, where radar estimates around 5 inches of rain occurred. Heavy rain also occurred between Bradenton and Fort Myers as well. Heavy rain is pushing into the Southwest coast this morning, and additional rounds of rain are likely through the day. Some localized flooding issues may crop up today. It’s the piling up of rain totals that will eventually shift this from a localized flood risk to a slightly more widespread one.

Additional rainfall expected by the NWS over the next week, with 10 to 15 inches on the southwest coast and 5 to 10 inches elsewhere in South Florida. (Pivotal Weather)

Additional rains of 5 to 15 inches are expected across South Florida from this morning into probably Saturday before things settle down. Locally higher amounts cannot be ruled out.

What’s next for the moisture plume?

We’ve got two aspects of this thing to watch. The first, and perhaps the best chance of tropical development over the next week is this disturbance crashing into southwest Florida this morning. It is expected to cross the Peninsula, emerge north of the Bahamas and may have a window of opportunity to develop into something in the Atlantic as it exits out to sea. This isn’t an especially uncommon early season mode of tropical formation, so this makes sense.

The National Hurricane Center is giving this disturbance crossing Florida today about a 20 percent chance of development as it emerges north of the Bahamas and scoots out to sea. (NOAA NHC)

The NHC is offering up only 20 percent odds of development today with this as it scoots out to sea. This seems to be as good of odds as are necessary at this point, but it is our best development opportunity through the weekend.

The second aspect of the moisture plume is where it actually ends up next. It abruptly shifts off Florida beginning Saturday as high pressure begins to build in from the west. This should help dry Florida out a bit after Saturday.

Sunday evening’s upper air map from the European ensemble shows high pressure building over Florida and an upper-low over the Bay of Campeche. This should allow the moisture “firehose” to get directed toward the Central Gulf Coast initially. (Tropical Tidbits)

This shift will allow the “firehose” to move west and focus on the central Gulf Coast by later Sunday or Monday. This should allow for locally heavy rainfall between Pensacola and New Orleans and at least some localized flash flooding potential.

From here, things get tricky. The European suite of modeling focuses in Texas next week, with its AI model aimed near Houston and the traditional operational model aimed at the Corpus Christi area south into the Rio Grande Valley. It’s tough to get a good signal in the ensemble modeling with a focus on the Louisiana coast within the GFS ensemble and a focus somewhere broadly in Texas or even Mexico on the European. Much, if not everything will depend on exactly how the weather pattern over the U.S. evolves next week. Stay tuned on this.

What of the late period GFS “Scareicane?”

Avid model watchers will note the sub-960 mb low that emerged in the Gulf of Mexico on a couple GFS operational model runs yesterday. Suffice to say there is little to no support for that particular outcome from any other weather model. And, in fact, the last two GFS model runs did not contain that feature. As a reminder, that is a normal GFS June bias to explode tropical systems unnecessarily strong in the Gulf. Bottom line: We offer it little to no credibility.

That being said, there does continue to be support for broad low pressure somewhere in the western Gulf of Mexico next week.

Normalized sea-level pressure anomalies over the western Gulf of Mexico remain low during days 6 through 10, but trying to extract a specific tropical entity from this soup will be a bit challenging. (Tropical Tidbits)

But whether or not we’re able to pull a specific system out of this general unsettled soupy mess of moisture remains to be seen. I think that potential next week is legitimate, but I think the ceiling on intensity is capped. We’ll keep watching this. In the meantime:

  • The GFS operational scare runs from yesterday are likely illegitimate.
  • There is broad support for something potentially in the western Gulf next week.
  • If something does develop, most likely it’s a strung out, sloppy storm and whether it goes toward Mexico, Texas, or to the north remains to be seen.

Stick with us as we watch!

A very unsettled, moisture-filled Gulf of Mexico remains the focal point of the next couple weeks

Headlines

  • Significant increase in rain chances for Florida this week will likely begin to lead to some flooding concerns, mainly for the Peninsula.
  • A firehose of moisture should begin to extend north and west from the FL Peninsula next week.
  • Portions of Florida will likely see 10 to 15 inches of rain or more through next week with chances of double digit rainfall totals expanding to the west in time.

Gulf moisture surge ahead

Put simply: The next 10 to 14 or so days in the Gulf of Mexico will feature a firehose of moisture that is likely to have wide ranging impacts from Florida to perhaps Texas. Ultimately this may serve as a reminder that a system does not need to be a hurricane or even have a name to cause widespread impacts.

Deeper tropical moisture (In green and blue) will focus on Florida this week and then begin to migrate to the west across the Gulf Coast next week (Pivotal Weather)

What’s the meteorology behind this?

Here’s the basic, high level meteorology of how things will begin to unfold. First, a trough of low pressure in the upper atmosphere is digging into the Eastern U.S. this week. What it will begin to do is draw moisture that’s been percolating in the western Caribbean and Central America northward. As high pressure builds east across Texas and into Louisiana, the focus of this moisture plume will be over Florida. Widespread daily rain and thunderstorms will begin to add up across the Peninsula. Eventually, high pressure may flip flop and end up over the Southeastern US, allowing the moisture plume to begin migrating west across the Gulf, soaking the Florida Panhandle, central Gulf coast, and eventually Louisiana or perhaps Texas.

A deep plume of tropical moisture is going to migrate from Florida this week into the central or western Gulf next week. As it does, heavy rain and at least a low risk of disorganized tropical development will go with it. (Tropical Tidbits)

Where is the rain going?

All modeling agrees that the Florida Peninsula will get doused this week. The models split rather drastically beyond this week. Some aim the tropical moisture more at the central Gulf Coast. Others push it to Texas. There’s very little agreement or consistency in the modeling on this aspect of the forecast, so for now the rain focuses on Florida and by next week we’ll be watching elsewhere.

The exact placement of high pressure will help orient the moisture plume, which is why it’s a bit soon to say what the second round of this does. This is in some ways like forecasting where exactly an atmospheric river will make landfall on the West Coast. You know that there will be a whole lot of moisture coming, but is that going to Texas? Louisiana? Mississippi/Alabama? We don’t know yet.

Will we see a tropical storm or worse out of this?

Most likely no, but it cannot be entirely ruled out. Several model runs on several different models, along with multiple ensemble members on various models have been showing some low-end development. The trouble is that the consistency and persistence of it is far too volatile to lend any specific outcome credibility. This is not a total surprise for June; storms in June are most often sloppy. About 70 percent of all named storms in the Gulf in June end up remaining tropical storms, while 30 percent have become hurricanes. As of now, we’ve got no reason to think a well-organized tropical system will come from this.

It’s probably just going to be rain in Florida then, so it’s not a huge deal, right? Incorrect.

Moisture plumes traversing record warm Gulf of Mexico sea-surface temperatures do not exactly make for optimal combinations anytime of year, let alone June. This moisture has some teeth, and we’ve seen this reflected in some of the maximum precipitation forecasts showing up on operational models. These have ranged from 15 to 25 inches in some cases between about Louisiana and Florida. That would be a lot of rain for anyone. Since we want to focus on the next week, looking at Florida tells the story. Maximum rain forecasts are basically 8 to 20 inches in the southern half of the Peninsula.

The rainfall forecast for Florida over the next week shows nearly 20 inches possible for the southwest, Lee Island, and Paradise coasts. (Pivotal Weather)

While there has been burgeoning drought here, anytime you get this much rain, it causes problems. I would expect flood watches and other notifications to get hoisted this week. If you’re planning a trip to South Florida, all we can tell you is to be prepared for more storms than usual and have some indoor plans setup, especially as this week progresses. And have a way to receive weather alerts.

Elsewhere, no other tropical concerns exist at this time and our focus will be entirely on this Gulf mess through the week.

The Gulf of Mexico sees a big influx in moisture next week but development odds remain on the low side

Headlines

  • Weather pattern change over Florida leads to much wetter conditions next week.
  • Model support for any tropical spin up within that pattern change is minimal.
  • The broader Gulf will likely see an increase in moisture after Father’s Day with a minimal chance at development, but all of that is likely to be battling a burgeoning U.S. early summer heat wave

Near term calm continues, but Florida gets soggy!

No tropical development is expected in the Atlantic, Gulf, or Caribbean over the next 7 days.

The biggest change over the next few days will be the increase in moisture over Florida. We noted this a couple days ago as more of a next week thing, and it appears that is on track. A few typical Florida thunderstorms are likely through the weekend, but next week sees a significant change. Precipitable water, or how much moisture is available in the atmosphere surges to about 150 percent of normal. This leads to a more significant dose of rainfall for the dry Florida peninsula.

Rain totals next week of 2 to 5 inches on average seem likely across Florida. Forecasts vary a bit in terms of where exactly the firehose is pointed, but for a decent portion of Florida, it will be a change from recent dryness. (Pivotal Weather)

There continue to be a very small minority of ensemble members or models that try to formally develop a weak, disorganized tropical system within this moisture plume near Florida next weekend. I am not really buying into this being a serious concern, but certainly all this rain in Florida could yield some localized flooding concerns eventually.

Next item in the Gulf? Maybe?

The Gulf is getting a little confusing, and you’ll need to parse this into two separate things. First, you have the Florida stuff and the very low potential for a spin up there next weekend, as laid out above. Secondly, you have this gyre-like feature that looks to sit over or near the southern Gulf, Yucatan, or southwest Caribbean after next weekend. There has been on-again/off-again development, especially on the GFS model, which you expect to see in June. We’ve discussed its poor overdevelopment bias in this region. But there has actually been some modest support for something in this region from the Euro too.

Broad lower than normal sea-level pressures are forecast by the European ensemble across the Gulf during days 11 through 15, with Tuesday the 18th shown above. (Tropical Tidbits)

What will be interesting with respect to this is that as this starts to become a feature, it will have to fight against a burgeoning hot summer pattern expanding across most of the Lower 48, including Texas and the South.

The same European ensemble shows a sprawling upper level area of high pressure from Texas into the Ohio Valley that will produce strong summer heat and will likely exert pressure on the developing slop in the Gulf. (Tropical Tidbits)

Even looking under the hood at things, that high pressure could be even a bit stronger than shown. If we assume that high pressure beefs up like this as shown and you get a drop in pressure with moisture pooling in the Gulf, it creates an interesting scenario where it may just dump over the Gulf or get squeezed into Mexico or coastal South Texas. I would probably lean against any organized development, but coastal areas of the Gulf could see an uptick in storm activity if this pattern comes to fruition, while inland areas bake.

Either way, it’s a story to monitor over the next week or so. But if you’re looking for a truly busy start to hurricane season, you may need to keep looking.

Are model shenanigans in the eastern Gulf next weekend realistic?

We got so many emails in response to our post on Monday, so thank you for everyone’s interest. We are going to work on some solutions for sponsorship or support and get back to those of you who replied as soon as we can. Thank you!

Headlines

  • Quiet persists into midweek next week.
  • The GFS model is bullish on a possible system next weekend in the Gulf.
  • Digging into model data seems to suggest that a weak, sloppy system or just a disorganized plume of moisture is most likely in the central or eastern Gulf toward Florida late next week or weekend.

Quiet through early next week

So, just to kick things off with some clarity, there are no systems expected over the next week. Everything looks quiet through at least midweek next week.

Eyeing up the southwest Caribbean & Gulf next weekend

What’s showing up?

One common theme of June with tropical weather is the GFS operational model getting overly excited about potential development in the Gulf or Caribbean. It is a known model bias. It happens every year, and if we had a dollar for every GFS model run that showed a system that never happened, we’d be able to buy quite a few pizzas. All that to say that it’s at it again today.

The last 8 runs of the GFS operational model with several runs showing some sloppy tropical system hitting somewhere in the Gulf or Florida around next weekend. Inconsistency at its finest. (Tropical Tidbits)

We’ve seen several runs now of the GFS showing a storm around next weekend in the Gulf or near Florida. In June, the first question I’d ask when I see this is whether or not there is any ensemble support for such an outcome. Recall, these operational models are one-run/one-solution outcomes. Ensembles are when tweaks are made to the initialization of the model and it gets run 30 to 50 different times, producing more of a spread in outcomes. This offers a more realistic view of what the outcome of a pattern may be. When we look at the GFS ensemble, we see a number of ensemble members producing something in the Gulf or near Florida.

GFS ensemble members showing possible outcomes of what is shown above next weekend, with solutions ranging from nothing to moderate tropical storms in the eastern Gulf. (Weathernerds.org)

Bear in mind that none of these are major storms. June storms, even with really warm water are likely to struggle because of wind shear. It’s still early. It is also why we tell people that there is no real correlation between how much activity there is in June and what we see over the peak of the season in August through October.

We have some ensemble support in the GFS, so the next question is whether or not we have European model support. We don’t. None of the 51 European ensemble members show anything meaningful.

What’s most likely?

While we have the GFS showing a system and the Euro showing nothing much, let’s look closer at how much precipitation the ensemble models show between June 11 and 17.

A comparison between the Euro and GFS ensemble mean of precipitation anomaly June 11-17 shows both models in agreement on a wet pattern for the central or eastern Gulf into Florida. (Tropical Tidbits)

Interestingly, but not surprisingly given what we know, both models are in agreement on above normal rainfall between June 11th and 17th over the central and eastern Gulf and Florida in particular.

Between what the models show and what we know about early to mid-June in the Gulf, it would be plausible to expect either a disjointed “plume” of moisture lifting north and northeast across the Gulf next weekend. Or, less likely but not improbable, a sloppy, marginally organized tropical storm moving in that same direction. Either way, Florida has been in a dry stretch lately, with developing drought, so any rain would probably be more welcome than anything.

60 day rainfall percentage of normal in Florida shows most of the Peninsula receiving about half their usual rainfall, or even less. (High Plains Regional Climate Center)

Whatever becomes of this potential next weekend, it seems this area in the southwest Caribbean or southern Gulf may be one to continue to at least keep tabs on deeper into June. We will continue to watch!