THE Surf Report

 

No Complaints.

SURF:

If you're a surfer in California, things are looking pretty sweet right now. Lots of surf, great weather, plenty of spots lighting up- it doesn't get much better than this. And hopefully you saw some of those photos coming out of Northern California last weekend- wowza. Tired yet? Still got gas in the tank? Good- there's more coming. 

First up, a storm generated some short period NW swell and is filling in this evening. For Friday, look for shoulder high surf that drops quickly into Saturday. By Sunday we're back to nice weather and waist high+ surf. And here are the tides, sun, and water temps for this weekend:

• Sunrise and sunset:
• 6:42 AM sunrise
• 4:44 PM sunset

• Water temps are 63 +/-

• Tides are back to normal this weekend:
• 3' at sunrise
• up to 4.5' at lunch
• and down to 1' at sunset

FORECAST:

The week starts out small but still rideable with a new small NW for chest high sets. Mid week looks small too but clean- and then we have more swell moving in towards Wednesday. 

Charts show a good storm above Hawaii sending more WNW for shoulder high+ surf into Friday. The Aleutians take a breather after that but the N Pacific looks to be active into December so we may have more surf by mid-month. If anything changes between now and then, make sure to follow North County Surf on X.

WEATHER:

The showers have moved through today (about 1/4" along the coast) and we have good weather until at least mid-week. After that, models diverge but showers MAY return next weekend. Until then, here's what we have on tap:

• Friday and Saturday: Sunny and cool. Temps 65/48
• Sunday through Wednesday: Slightly warmer and temps 70/55.
• Late next week: A return of showers?

BEST BET:

• Friday with shorter period WNW and clean condtiions
• Wednesday with better WNW

NEWS OF THE WEEK:

Now that El Nino is charging full steam ahead, what should we expect once winter kicks in towards January? The National Oceanic and Atmospheric Administration (NOAA) can shed some light on the subject for us:

After the last three winters of La Niña conditions (weren’t we all ready for a change!), the tropical Pacific is looking much different this year, with a strong El Niño likely this winter. Historically, how has El Niño shaped precipitation (rainfall + snowfall) over the U.S.? Let’s dig in and find out.

What happened during December-February for previous strong El Niños?

For the 7 strongest El Niño events since 1950, wetter-than-normal conditions occurred along the West Coast and southern tier of the U.S., especially in the Southeast. This is expected because El Niño causes the jet stream to shift southward and extend eastward over the southern U.S. However, there are clearly some differences among the events if you look at the details in the maps. For instance, the 2015-16 and 1957-58 strong El Niños were not as wet as expected over the southern U.S. and were even dry in some locations. What is the story there?

The devil is in the details.

When forecasters put together a prediction, one consideration is the forecasts generated by climate models, such as from the North American Multi-Model Ensemble (NMME). You might think that the NMME produces a single forecast map for the upcoming winter, but nope! Each month, the NMME produces hundreds of forecast maps from several different models. Why so many maps? Well, the short version of the story is that the chaos of weather can have big consequences for our seasonal predictions. We cannot possibly say what the weather will be like on January 1st based on model forecasts that were made in early November. So, by running models many times, we are simulating a lot of different possible “weather outcomes” that can occur over a season. 

The easiest way to examine these model predictions is not by staring at hundreds of maps (trust me, we’ve tried), but rather by examining the average of all the maps (this is called an “ensemble mean”). The average isolates the seasonal forecast signal (like El Niño) while removing the noise of chaotic weather. The forecast averages are expecting a strong El Niño this winter; not surprisingly, bears a striking resemblance to the expected winter El Niño precipitation pattern.

However, this is a bit misleading because, as just noted, there are actually hundreds of forecasts, and this is just an average of all of them. We know, because of chaotic weather, that the upcoming reality could more closely mimic any of the hundreds of individual forecasts. And these forecasts can differ considerably from each other. 

For example, one forecast that looks quite similar to the NMME average. On the other hand, another has taken from the same model from the same starting month with basically the same El Niño, has almost the opposite pattern! And we cannot rule out either outcome actually happening for the upcoming winter! 

This, in a nutshell, is the curse of internal variability. Basically, a single model, run forward with slightly different initial states, can lead to very different forecasted outcomes for the upcoming El Niño winter. 

So, what’s the point of a making winter predictions?

If I’m basically saying that anything can happen this winter, then why do we bother to produce seasonal predictions? Well, as we have emphasized on the blog, although almost anything can happen in a given winter, El Niño or La Niña can tilt the odds in favor of a particular outcome, meaning that those hundreds of predictions may lean in a certain direction. Additionally, the stronger the El Niño, the more likely the U.S. winter precipitation pattern will match both the average of the computer model forecasts and the typical El Niño precipitation pattern. Because there are higher chances in certain outcomes (e.g., a wetter winter), the presence of El Niño can help users assess risk and make plans. 

Not convinced yet? We can put my claim to the test by assessing how well the typical or expected El Niño winter precipitation pattern matched up with what actually occurred for past winters. We can do that by examining all previous U.S. precipitation forecasts produced by the NMME, the hundreds of individual forecasts and the multi-model average, for all past winters from 1983-2022. The schematic above breaks down these evaluations.

I have taken every winter precipitation pattern from this period and calculated how well that pattern matched the individual NMME forecasts for that winter, the NMME average forecast, and the expected El Niño precipitation pattern. The values in this evaluation range from -1 to +1, with values closer to +1 indicating a good match with the actual observed pattern, values near 0 indicating no match, and negative values closer to -1 indicating an inverse match (“mirror image”). All these calculations for all 40 winters are presented in a single plot and arranged from left to right according to the strength of the La Niña (strongest farthest left) or El Niño (strongest farthest right), as shown in the bottom left of the schematic.

There’s a lot to take in from these comparisons, but there are three main takeaways:


The first in this sequence reveals two of the main takeaways.

The stronger the El Niño or La Niña, the more likely that the actual winter pattern will match the average model forecast pattern. This is why seasonal predictions work, and why we care so much about ENSO! The tendency is for the average model forecast to perform better at stronger Niño-3.4 index values. In fact, by this metric, the forecasts have performed quite well for most (but not all! – more on that below) moderate-to-strong El Ninos.

For a given winter forecast, chaotic weather causes a wide range of performance among individual model forecasts. This second takeaway, which causes the most wailing and gnashing of teeth among forecasters and their users, is the performance from individual model forecasts. In fact, for a given winter, there are usually some forecasts that perform quite well and some that perform quite poorly, even though there are no major differences in the models’ ENSO forecast between the high- and low-performing forecasts. Instead, the main difference is what we saw in those two forecast maps above: unpredictable, chaotic weather. Unfortunately, it’s likely impossible to distinguish those high- and low-performing model forecasts well in advance. Again, that’s the curse of internal variability.

In the second step of this sequence, we now look at how well the observed precipitation pattern matched the expected El Niño or La Niña precipitation pattern.

This addition reveals the third takeaway.

The average model forecast closely resembles the “expected” El Niño/La Niña precipitation pattern for most winters. This point comes out when we consider the average model forecasts, that represent the El Niño or La Niña precipitation patterns for a given Niño-3.4 index value. This is the models’ way of agreeing with what we’ve been claiming at the ENSO Blog for years: ENSO is the major player for predictable seasonal climate patterns over the U.S. If there were another more important source of predictability, we would expect a bigger separation between those colored diamonds and the dark grey dots.

The comparison between the two biggest previous El Niños in this record, the winter of 1997/98 (a forecast success) and 2015/16 (widely regarded as a forecast “bust,” or how forecasters generally describe a bad forecast), are a great illustration of this final point. but the upshot is that the influence of chaotic weather variability could have reduced the 1997/98 forecast performance much more than it did, and it likely was a factor in why the 2015/16 forecast performed so much worse.

Finally, let’s put these comparisons in the context of the forecast for the upcoming winter.

The likelihood of a strong El Niño increases the chance that the precipitation pattern for the upcoming winter will match both the NMME average and the expected El Niño pattern reasonably well, but, as I have been emphasizing, we cannot rule out the possibility that reality will have other plans.

That’s awfully convenient!

At this point, you might be saying, “Hold on, you’re telling me that ENSO is the main driver of the winter precipitation outlook, and if it busts, we can just blame it on the noise of chaotic, unpredictable weather? That sounds like a cop-out (and a little suspicious coming from a writer for the ENSO Blog).” That’s a fair question! As scientists, we need to continuously reevaluate our assumptions, check for blind spots, and tirelessly strive to improve our understanding of our forecast models. I can assure you that these efforts are being made, especially when the seasonal conditions deviate from expectations, and hopefully they will lead to better seasonal predictions with higher probabilities.

The main point I’m trying to make, however, is that when a forecast busts, it isn’t necessarily because there is a clear reason, a model bug, or a misunderstanding of the drivers. It could just be because there is a certain amount of unpredictable chaotic weather that we cannot predict in advance. That means that we must remember that seasonal outlooks are always expressed as probabilities (no guarantees!) and that we need to play the long game when evaluating seasonal outlooks – a single success or bust is not nearly enough.

BEST OF THE BLOG:

Want to give a big THANK YOU to everyone that RSVP'd to this Friday's Hollowday Party, benefiting the Maui Strong Fund!

This year's charity event, presented by our friends at Venture LLP, will be at Master's Kitchen & Cocktail in culinary hotspot Oceanside, CA. An industrial space with classic history, Masters was once a well remembered drag car shop. The revamped restaurant kept its authentic character, and is the perfect spot to get you in the holiday spirit. And with this year's fundraiser, we'll be benefiting our fellow Hawaiian surfers through the Maui Strong Fund, supporting the rebuilding of historic Lahaina town. And it couldn't be possible without YOU and our auction sponsors:

• Electra Bicycles
• Surfhouse and Coffee Coffee
• Solterra wine from payrollHUB
• Mark K. Ley fine art
• The Cottage Restaurant
• Canvas print from the North County Board Meeting
• Whit Aadland from Whit's Musician Devolpment
• Captain Fin Co. x Thomas Campbell x Type G
• Caves Wine Shop
• Lightning Bolt Surfboards
• and Alila Marea Resort

And just a reminder that dinner, drinks, live music, and auction gets started at 5:30 PM. Thanks again for the support and we'll see you then! 

PIC OF THE WEEK:

A lone surfer in south county SD having the time of his life. We should all be so lucky. Oh- I guess we have been lately. Never mind.

Keep Surfing, 
Michael W. Glenn
Much Obliged
I Like To (Christmas) Party
Have Logged 3.8 Years Of Accumulated Tube Time To Date