Seasonal Outlooks

Checking in on where our El Niño event stands as we descend toward winter

One-sentence summary

Today’s post primarily dives into where we stand with El Niño currently and what sort of impacts that could have heading into winter.

Tropics: Quiet!

We’re all quiet out there at the moment in terms of anything meaningfully developing in either the Atlantic or Eastern Pacific basins. It should be a quiet week overall.

U.S. Weather: Warmth taking hold

Overall, it should be a relatively calm week across the country. We are not expecting too much in the way of severe weather or excessive rainfall this week. One could argue that there’s at least some interesting weather happening though. A storm today and tomorrow will bring more rain and mountain snow to the Pacific Northwest. Another may follow toward the weekend. Overall, these systems look relatively minor on the atmospheric river scale this week.

The beefiest moisture this week off the Pacific will be aimed at British Columbia, with overall minor atmospheric river impacts. (UCSD C3E)

A pair of systems will bring rain and snow to the Great Lakes and southern Canada through the week. And a relatively strong system will bring showers and thunderstorms to portions of Texas later this week. There should also be a rather significant winter storm in southern Alaska later this week as well.

Temperature-wise, it looks like a very warm week nationally. Multiple record highs will be threatened from the Southern Rockies to the Carolinas this week, including close to 20 tomorrow.

Temperatures this week are expected to be above to much above normal across the Ohio Valley and Mid-South into Texas. Cool temperatures prevail primarily in Ontario, Quebec, and the Maritime Provinces. (Tropical Tidbits)

Not terribly cold in most of the country.

Updating El Niño: It’s here and still strengthening

To this point, I don’t think I would describe the behavior of the current burgeoning El Niño as “classic” in many ways. It’s basically already a “strong” El Niño event, and while its influence is there it is not complete just yet. For example, if you look at just sea-surface temperatures in what we call the El Niño box in the tropical Pacific, the current event ranks about 7th strongest since 1950 (based on the Oceanic Niño Index, or ONI).

If you focus on the 2nd and 4th charts, which date back to last December, you’ll see that the Niño 3.4 region has been slowly strengthening, while the 1+2 region (bottom) has been strong for months. (NOAA)

However, if you look at another dataset called the Multivariate ENSO (El Niño) Index, or MEI, this event is only the 9th strongest since 1979 (which is probably around the 14th or 15th highest since 1950). Why am I sharing these data points with you? Well, the ONI is looking purely at ocean temperature. The MEI is typically a better index in that it factors in other variables, which we would liken to how the atmosphere is responding. So the ONI can be a proxy for ocean response, whereas the MEI can be a proxy for atmospheric response. To this point, the atmosphere has not yet responded to the same extent as the ocean has.

But that may finally be changing. I shared the chart above showing the sea-surface temperature anomalies in the various different El Niño regions of the Pacific to highlight the differences between the 1+2 region (bottom panel, which is the eastern Pacific) and the 3.4 region (2nd panel from top, which is closer to the International Dateline.). The eastern Pacific has been revved up since spring. The central Pacific took a bit longer, but it finally appears to have hit a level where it should allow for El Niño to become the more dominant feature for global weather.

And if anything, this event is likely to intensify further in the next couple weeks. So if you’ve been wondering if this El Niño was going to show up like a typical strong El Niño, there may be reason to assume it will.

What does that mean? No relationship is perfect, but in general, El Niño has a decent correlation to a couple key elements here in North America.

El Niño relationships typically yield a cool, damp Southern U.S. and a warm North. (NOAA)

Generally, we see a cooler, wetter Southern U.S. and northern Mexico, as well as a milder Canada and northern tier of the U.S. into Alaska. Usually more storms will crash into California during El Niño winters. Sometimes, like in 2015-16 that isn’t the case. But on average, it is. Seasonal climate models are fairly confident in a warm North/cooler South but a bit split right now in terms of how they view precipitation. An American climate model, the CFS, shows a rather classic wet California and wet Texas through Southeast. The European model has the second part but shows near-normal to just slightly above average precipitation in California.

The bottom line at this point is with El Niño strengthening, one should expect the atmospheric response to also strengthen over the next couple months. And with a rather strong El Niño in place, that response would probably look similar to what is typical in El Niño as shown above. Of course, there are risks as noted, as well. I also think there are wild cards.

If you look at sea surface temperatures around the world right now, virtually all Northern Hemisphere oceans are warmer than normal.

Sea-surface temperature anomalies show almost the entirely Northern Hemispheric ocean system warmer than normal, and in some cases record warm for this time of year. (Weather Bell)

Why does this matter? We are in a bit of uncharted territory. One of the big reasons El Niño is such a big deal is not just because where it occurs is so important to global weather but also because it’s often so anomalous relative to other global sea surface temperatures. It becomes a dominant feature. Well, what happens when you trigger an El Niño on a planet with a lot of oceanic temperatures that are also extremely warm, relative to average? We’re going to find out this winter. While the smart money is probably still on El Niño leading to El Niño things, there is at least some chance the typical impact could be perhaps a bit muted because the majority of the planet is so much warmer than normal. Would I bet on that? No. Am I watching it as a forecaster? Yes.

Suffice to say, we live in interesting times.

Taking stock of the 2023 Atlantic hurricane season so far: Active with headwinds; more to come?

One-sentence summary

With the historical peak week of hurricane season upon us, we take a look at what has happened so far, how seasonal forecasts have performed, and what we can glean for the rest of hurricane season based on the active start and El Niño.

How are those seasonal forecasts holding up?

Back in June when we launched The Eyewall, one of the things we did was dive into the components of the seasonal forecast. We explained that the 2023 hurricane season would be trickier than normal, as the developing El Niño, which typically reduces storm activity would be battling an outrageously warm Atlantic Ocean, a feature that would be good for busy storm activity. So far, that battle seems to be exactly what’s playing out. The “consensus” forecast was 16 named storms, 7 hurricanes, and 3 majors. As of Monday, we sat at 12 named storms, 3 hurricanes, and 2 majors.

Our accumulated cyclone energy for the season, or ACE, sits around 125 percent of normal for the first week of September.

As of yesterday, the Atlantic was running about 125 percent of normal activity, from an ACE standpoint. (Colorado State University)

If the season ended right now, we would be sitting in the upper tier of “below normal” seasons. In other words, we already have one heck of a base and seem to be on our way to (at worst) an average season. The seasonal forecasts did a good job telegraphing this, and frankly some of the more active seasonal forecasts that I believed were more out of an abundance of caution are the ones most likely to verify.

And this isn’t because of ticky-tack storms that last a day or two. Idalia, Don, and Franklin, the three hurricanes account for nearly 75 percent of the seasonal ACE to date. So three legitimate storms make up the majority of the total. Back in June we said that we believed the Caribbean would struggle (it mostly has), the eastern Atlantic would be busy (it’s been more the central Atlantic, so that point is a little fuzzier), and that the most concerning items this season would be systems forming close to home (Idalia counts for that). So thus far, this is going mostly as expected, if not a little bit busier. Kudos to the seasonal forecasters for not just going all-in on El Niño.

Where are we going?

Well, this week we are likely to see another big jump in seasonal ACE when Lee forms.

The likely track of future Lee should go north of the islands but may impact Bermuda. It’s going to be a very strong storm. (Tomer Burg)

From our morning post, you can read how we expect that to become a major hurricane, likely at least a category 4 storm. This will be a big ACE adder, and I suspect we’ll see things shoot up at least into the 70s once Lee is done, pushing us into the “average” tier of seasons if it ended right there. Behind Lee, we may get another storm in the eastern Atlantic, so there’s an opportunity for a few more ACE units.

But here’s something. If you look at the European ensemble model forecast for wind shear in days 11 to 15, which pushes us out to near September 20th now, you can see that the Gulf and western Atlantic are ripping with shear.

Wind shear is forecast to remain well above normal in the Gulf and western Atlantic for mid-month. (Tropical Tidbits)

If that happens as forecast, anything in the Gulf will struggle, as would anything coming out of the Caribbean. However, the lower wind shear in the eastern Atlantic and central Atlantic suggests these would be the areas where storms could continue to form, continuing the legacy of the 2023 season to date. We may see less hostile conditions return to the Gulf and western Atlantic in the final days of September, but that’s obviously a long way off.

What does El Niño tell us?

Quite frankly, if we assume that El Niño is up and humming now and the influence is strengthening, then we should expect to see a lot of what we’ve already seen for the remainder of hurricane season. Here is a map of all hurricanes in Septembers and Octobers since 1950 when the Oceanic Niño Index (ONI) was 1.0 or greater for June-July-August (this year’s value is 1.1).

Hurricane seasons most similar to this one in terms of El Niño produced a lot of central Atlantic storms in September and October and not a lot of serious land impacts. (NOAA)

With a couple notable exceptions, this map shows a lot of fish storms and middling systems in the western Atlantic. The two most notable exceptions were Joaquin in 2015 which killed 34 people (33 of whom were aboard the El Faro). And also Betsy in 1965, which killed 81 and inundated New Orleans. Emily in 1987 hit Hispaniola and Bermuda. And I think that sums up the season so far: A lot of middling storms and mostly fish storms with one potent hit in Idalia.

All in all, given what we see on the maps right now and given how this season has gone, there are two primary areas that probably should watch for land impacts: Bermuda and the Greater Antilles. If we can relax shear enough late in the season and get a disturbance in the Caribbean that comes straight north, you never know what you can get out of that, and those often threaten Cuba, Jamaica, Hispaniola or the Bahamas. Bermuda remains in the target line I think for at least one or two more storms. Lastly, the eastern Gulf or off the Southeast coast may be secondary areas to watch, given the warm waters and potential for just the right things coming together at the wrong time, sort of like what we saw with Idalia and to a far less impactful extent, Harold in Texas earlier this season.

Will it be enough to drive ACE above normal for the season in the end? I’m not certain, but it will be close.

June 9, 2023 Outlook: Tying together the seasonal forecast pieces

Happy Friday! Congratulations, we made it through the week without a named storm. Let’s do it again next week. There’s not a lot new to add forecast-wise today, so we’ll keep it brief and then tie together all the threads of our seasonal outlook below. Next week, we’ll touch on dust, and look for a bit of a longer-form piece on the spate of recent major hurricanes in the Gulf of Mexico and what it does or does not tell us about the future. A lot of effort went into that and I think it’s important to understand, so I hope you’ll check it out next week.

Meanwhile, be sure to give our social feeds a follow on the right (or bottom on mobile) and spread the word to your family and friends on the East Coast, Gulf Coast, Atlantic Canada, Caribbean, or Central America!

One-sentence summary

No tropical development is expected over the next seven to ten days.

Happening now: All’s quiet

Take a quick peak at the satellite image across the Atlantic basin, and while it’s definitely not quiet, there is nothing of note anywhere out there, as you expect in June.

We’ve periodically seen flare ups of storms across the basin, though this morning isn’t too bad. The loudest area is off Cuba and in the Bahamas. Noisy at times, yes, but nothing is organized. (College of DuPage)

The medium range (days 6-10): Still nothing

We continue to watch for activity to get a little more interesting late, but through day 10 at least, there’s nothing to really speak of out there.

Fantasyland (beyond day 10): No change in thinking

We explained yesterday in some detail why we did not believe the operational GFS model. We continue to hold those truths to be self-evident today.

Tying together the seasonal outlook: “Average” is the path of least resistance

On Tuesday we talked about the various seasonal forecasts from different government, private sector, and academic institutions. On Wednesday we noted how El Niño makes a convincing case for a quieter hurricane season. But yesterday we noted how the Atlantic Ocean was in a condition that typically correlates with very active seasons.

So what do we make of all this?

Well, yesterday, NOAA declared that we’re officially in an El Niño now. This gives us a bit of confidence that we’re going to maintain at least a weak, if not a moderate El Niño (or stronger) through the peak of hurricane season. The wind shear imparted on the Atlantic by El Niño is a tough barrier to get past. It would be difficult to expect an active hurricane season given El Niño. But given the setup in the Atlantic, it seems difficult to expect this season to behave quite as quietly as past El Niño seasons. One need only look at the European model forecast for the season to see this.

The ECMWF (European model) is calling for an above average season of activity in the Atlantic basin. (ECMWF)

It calls for an above average hurricane season. It says, to heck with El Niño, the Atlantic is blazing, let’s rev it up! I think it’s notable to look back to last year in June, however. The ECMWF was also calling for a very active season (as were most of us), and that did not materialize. Last year was “average” statistically.

So given all this, I call forecasting an average season the path of least resistance. What I ultimately think could happen is that the Caribbean struggles due to shear, the eastern Atlantic is very busy, and the most concerning items this season will be systems close to home that form when wind shear relaxes some, possibly off the Southeast and in the Gulf. I believe it will be tough to relax shear enough this season to produce the ultra high-end storms we’ve seen in recent years, but that’s completely speculative on my part. We’ve also seen some instances in recent years where shear has actually helped some storms along, depending on where exactly it was placed. So never say never.

Back on Tuesday I said that the consensus forecast (16 storms, 7 hurricanes, 3 major hurricanes) was as good a forecast as you could offer right now. I stand by that, with perhaps slightly higher odds for a little under those hurricane/major hurricane numbers.

As always, prepare for the season the same way you would if we told you it was be insanely active, which is to say: Know your zone, have a plan, build a kit.

Enjoy the weekend. We’ll be back with you again Monday!

June 8, 2023 Outlook: Continued quiet for a bit longer

Thanks to Eric for covering yesterday. Much like we do with Space City Weather, he and I will split duties, though I’ll spearhead most of this site, as he does with Space City Weather. Today we’ll discuss more about why the GFS model is probably getting the day 10+ range wrong. We’ll also tackle part 3 of our seasonal outlook which discusses water temperatures in the Atlantic.

One-sentence summary

The tropics are quiet, and we continue to believe that what is shown on the GFS model late in its forecast period is not a serious concern.

Happening now: Not too much!

All is quiet across the tropics this morning with no disturbances of note. The main weather feature right now is an upper low near New England that has been responsible for directing Canadian wildfire smoke into the East.

Copious amounts of wildfire smoke have produced the worst air quality in decades in much of the Mid-Atlantic and New York. (College of DuPage)

While this is not directly related to tropical weather, it was noteworthy to watch the squashing of fair weather clouds as smoke moved into some locations in the Northeast. Reminiscent of how Saharan dust can help inhibit tropical systems. We’ll touch more on the dust situation next week.

The medium range (days 6-10): Nothing yet

We continue to see quiet conditions likely to continue through about day 10, so there is not much to discuss here.

Fantasyland (beyond day 10): The GFS is probably still wrong

We’ve talked about this for a few days now, but we also know that when something shows something adverse consistently, it can spark some concerns. Despite the fact that the GFS operational model has shown a substantial storm for multiple straight runs in the day 12 to 16 timeframe, we remain fairly convicted that it’s really nothing to worry over. Besides the fact that the GFS frequently gravitates toward “scareicanes” in the Gulf this time of year, Eric also touched on the ensembles not supporting it yesterday. That remains true today.

Only a handful of the 30+ GFS ensemble members show tracks of a meaningful tropical system on this “spaghetti plot” at the same time the GFS operational model shows one, indicating that, at the least, what happens probably will not do so as the operational model shows. (Weathernerds.org)

Operational model runs are really just that: One run of one model. It’s deterministic. This is what the model thinks is going to happen, and that’s that. Ensemble guidance is much more nuanced. You take those models, like the GFS or ECMWF (the Euro) and run it 30 to 50 different times with tweaks to how the model is initialized, the starting point that it bases the rest of the forecast on. By doing this, you get a more realistic set of possible outcomes than just what one deterministic model shows. And in the case of this rogue GFS model storm, the ensemble guidance offers little additional support for something like the operational model shows. And the European model? It shows nothing at all.

That said, there’s good reason to think that something may be afoot late. I touched on this a little back on Monday. But the overall background pattern is going to become a bit more supportive for rising air in the Atlantic.

The overall pattern late in the forecast period (after June 19th or so) is favorable for some sort of nonsense in the western Caribbean or southern Gulf, but it probably looks nothing like what the GFS operational has shown and may be a bit sloppier. It could even end up in the Pacific. Long way to go. (Tropical Tidbits)

Couple that with an upper level pattern that shows a mean trough (dip in the jet stream) over the Southeast, eastern Gulf, and western Caribbean, and that argues that, broadly, we look more favorable for tropical development toward the final 7 to 10 days of June. But probably not like what the GFS operational model is showing at the moment. We’ll see if this can roll forward as we move into next week.

The 2023 seasonal outlook Part 3: Atlantic Ocean water temperatures

On Tuesday we discussed what the outlooks were for the 2023 Atlantic hurricane season. Yesterday we broke down El Niño. Today, let’s look at the Atlantic Ocean. With the exception of the northeast Gulf of Mexico, the area off the immediate Southeast and Mid Atlantic coasts, and a chunk of the subtropical Atlantic, the entire basin is running hot, with widespread water temperature anomalies that are above normal.

Sea surface temperature (SST) anomalies from earlier this week across the Atlantic basin, with a couple exceptions, are on fire right now. (Weather Bell)

As Michael Lowry pointed out in his (always excellent) daily tropical newsletter yesterday, the eastern portion of the Atlantic is at its warmest levels on record for this time of year, and it is not really even close. Obviously, this is important. But just how important? If you look at page 9 of Colorado State University’s seasonal hurricane outlook from this month, you’ll find that eastern Atlantic SSTs have a nearly 0.6 correlation to seasonal accumulated cyclone energy (ACE). In simple terms: A warm eastern Atlantic this time of year typically produces active hurricane seasons.

It’s tough to find a true analog to this year though because a.) this is the record warmest and b.) no previous upper-end warm eastern Atlantic basin temperatures coincided with an El Niño event in the Pacific. But, looking at the Atlantic in a box, if you took the five warmest years outlined in CSU’s forecast behind 2023, you averaged 23 named storms. Big yikes. Compare this to what we said about El Niño yesterday, which averaged 9 storms. Those goalposts are wide enough for <insert the name of a football kicker who has undoubtedly made you angry at some point> to never miss. No one ever got into weather forecasting because it was easy.

So El Niño implies a weak hurricane season, while the current water temperature situation in the Atlantic implies an extremely active season. This is a tug of war and a half, and one of the most fascinating seasonal forecasting challenges I’ve ever seen. Tomorrow we’ll talk about some risks and tie a ribbon on all this.