The Emergency Boardriding System Is On Standby.
SURF:
Had some small but fun surf this week. AND the weather cooperated. AND the water warmed up after a brief letdown from 70 degrees to 60 degrees and back to 70 degrees all within a week.
I seriously think the water temps are harder to predict than the actual weather or waves. But besides all that, we've got some good surf headed our way, so let's get to it.
We had a small storm off New Zealand last week and that is sending us waist surf on Saturday with chest high sets late in the day. That swell builds further on Sunday for shoulder high sets by sundown. Look for small but SW on Saturday and better surf later Sunday. And here's the tides, sun, and water temps for the next few days:
- Sunrise and sunset:
- 6:31 AM sunrise
- 6:58 PM sunset
- Water temps are still slightly below normal (70 vs. 75) but I'd still wear trunks and a jacket if the sun was out.
- And pay attention to the tides this weekend:
- 1.5' at sunrise
- 5.5' at lunch
- and 1' at dinner
FORECAST:
Looks like the Emergency Boardriding System will need to be activated next week.
The building swell from Sunday will result in head high+ surf in N County SD and well overhead+ in the OC for Monday- along with a small NW that may help peak up the swell. The swell will most likely peak Monday and still be solid Tuesday morning.
The swell reformed as it headed towards South America and sent a 2nd pulse to give us more shoulder high waves on Wednesday (and bigger in the OC due to the S angle). On a side note, for all you surf jocks out there, I'm assuming the World Surf League will run their playoffs at Lowers on Monday- unless the swell is too big (a good problem to have). Regardless, make sure to tune in Sunday just in case. As far as next weekend goes, there will be some background SW/NW for more waist to chest high surf.
And further out, models show more modest SW from Antarctica (i.e. waist to chest high) arriving the first week of fall. It's about time!
And for you fans of Hurricane Olaf, Cabo is getting slammed tonight with 20'+ surf and will die before it hits our window. Won't matter though with the solid SW next week.
WEATHER:
Warm weather is on tap for Southern California this weekend. We have a slight heat wave inland on Friday/Saturday and a small chance of thunderstorms in the mountains, but here along the coast- just typical night/morning low clouds/fog and temps in near 80. Things slowly cool down next week and we get more extensive night/morning low clouds/fog. If anything changes between now and then, make sure to check out North County Surf on Twitter!
BEST BET:
Sunday with increasing SW or Monday-Wednesday with firing SW!
NEWS OF THE WEEK:
Summertime around here is an interesting cat. You would think living in a desert (yes, that means us So-Cal residents), we wouldn't see any rain during the hottest time of the year- our summer. But of course we do, as our mountains/deserts all summer long see flash flood warnings (like today) and we get the odd downpour here at the coast (which I can confirm during my lightening incident on 8/29). But what causes the monsoon moisture to surge into the Desert Southwest this time of year? Here's the National Oceanic and Atmospheric Administration to explain:
If you live in the U.S. Southwest or northwestern Mexico, you may already be familiar with the annual climate phenomenon called the North American Monsoon, especially since rainfall in some spots has been way above average this summer. In fact, this monsoon may turn out to be the wettest on record for some places. More on that later… Now, let’s take a sojourn through some North American Monsoon basics:
What is the North American Monsoon?
The North American Monsoon is a seasonal change in the atmospheric circulation that occurs as the summer sun heats the continental land mass. During much of the year, the prevailing wind over northwestern Mexico, Arizona, and New Mexico is westerly (blowing from the west) and dry. (Going forward, to avoid having to say “northwestern Mexico, Arizona, and New Mexico” over and over, I’ll refer to this area as “the monsoon region.”)
As the summer heat builds over North America, a region of high pressure forms over the U.S. Southwest, and the wind becomes more southerly, bringing moisture from the Pacific Ocean and the Gulf of California. This circulation brings thunderstorms and rainfall to the monsoon region, providing much of their annual total precipitation.
The monsoon starts to develop in Mexico in June, and moves into the U.S. Southwest in July. By early to mid-September, wind patterns have generally reverted back to the westerly pattern, bringing an end to the monsoon. There is some variability in the onset and demise of the monsoon.
If you live in the U.S. Southwest or northwestern Mexico, you may already be familiar with the annual climate phenomenon called the North American Monsoon, especially since rainfall in some spots has been way above average this summer. In fact, this monsoon may turn out to be the wettest on record for some places. More on that later… Now, let’s take a sojourn through some North American Monsoon basics:
What is the North American Monsoon?
The North American Monsoon is a seasonal change in the atmospheric circulation that occurs as the summer sun heats the continental land mass. During much of the year, the prevailing wind over northwestern Mexico, Arizona, and New Mexico is westerly (blowing from the west) and dry. (Going forward, to avoid having to say “northwestern Mexico, Arizona, and New Mexico” over and over, I’ll refer to this area as “the monsoon region.”)
As the summer heat builds over North America, a region of high pressure forms over the U.S. Southwest, and the wind becomes more southerly, bringing moisture from the Pacific Ocean and the Gulf of California. This circulation brings thunderstorms and rainfall to the monsoon region, providing much of their annual total precipitation.
The monsoon starts to develop in Mexico in June, and moves into the U.S. Southwest in July. By early to mid-September, wind patterns have generally reverted back to the westerly pattern, bringing an end to the monsoon. There is some variability in the onset and demise of the monsoon.
What impacts does it have on Mexico and the U.S. Southwest?
Rainfall associated with the monsoon is very important for the region. Northwestern Mexico receives upwards of 75% of its average annual precipitation from it, and Arizona and New Mexico more than 50%, during July–September.
For many of us, the word “monsoon” conjures images of heavy rain lasting for months. While that’s often the situation for the Indian monsoon, the monsoon in North America behaves a bit differently. The rainfall generally has a strong diurnal cycle, meaning a daily pattern of mostly dry mornings, storms developing through the day, and most rainfall occurring in the afternoon and evening. Some of these thunderstorms can be strong, delivering heavy rain and frequent lightning. Monsoon rainfall activity tends to be grouped into bursts, with periods of rainy days interspersed with drier periods, rather than rain every day. Also, the occasional eastern Pacific tropical storm can increase monsoon moisture and rainfall.
The impacts of the monsoon go beyond just rainfall amounts. There is also an important relationship between rainfall and temperature: usually, more rain leads to cooler conditions, and less rain leads to hotter conditions. One recent study explored the relationship between the monsoon and wildfires in the Southwest and northern Mexico, finding that monsoon rains were important for ending wildfires.
When was the North American Monsoon discovered?
The rainy season would have been critical for Native Americans for thousands of years, and, for some Native American tribes, continues to be so. Scientists first noted the seasonal rainfall patterns in the Southwest in the early 20th century, with the circulation pattern being understood as monsoonal by midcentury. A couple of field campaigns, including the Arizona-based South-West Monsoon Project (SWAMP, 1993) and the international North American Monsoon Experiment (NAME, 2004), provided a lot of observational data and resulted in a better understanding of the mechanics of the monsoon.
What affects the North American Monsoon?
Although there has been a fair amount of research into the monsoon, there are still far more questions than answers about how it works, and if the seasonal amount of rain, potential start date, or other characteristics can be predicted. I listened to the Southwest Climate Podcast from CLIMAS, the Climate Assessment for the Southwest, to learn more about what affects the monsoon and its rainfall, and how Monsoon 2021 is shaping up, and reached out to the podcast co-hosts, Zack Guido and Mike Crimmins, for help with this post.
Rainfall, as anyone who has read the ENSO Blog before will know, is an extremely complicated thing to predict. When you add in the sparse rain-gauge observations available in the U.S. Southwest and Mexico, it becomes even more difficult to make confident statements about the effects of the monsoon and how it can be predicted. In the podcast episode “2021—a generational monsoon?” Zack listed some of the factors that influence how much moisture is available to the monsoon, including the position of the high-pressure area, wind patterns, and transient weather features. Another player is land-surface feedbacks—wetter soils provide more moisture to the air through evaporation.
Zack also mentioned our good friend El Niño. Here at the ENSO Blog, we’re always curious about the role of ENSO (El Niño/Southern Oscillation, the entire El Niño/La Niña system). He pointed out that ENSO does influence Pacific tropical storms, which can supply moisture to the monsoon.
I did a quick comparison of the average July–August rainfall in the monsoon region with the Niño-3.4 index, using 70 years of records. Some earlier studies suggested that El Niño may be related to lower July–August rainfall, and La Niña related to higher rainfall, due to large-scale atmospheric circulation changes.
“Hey! But El Niño leads to more tropical storms than average,” you’re saying, because you’re not new here. “How would that result in less total July–August rain?” Good question! And yet another element of the monsoon system that needs more study to resolve.
How is climate change affecting the North American Monsoon?
Likewise, it’s not yet clear how the monsoon is changing in the warming climate, or how it will in the future. Zack and Mike mention that last year was an extremely dry monsoon, and this year is extremely wet. So is climate change increasing monsoon variability? It’s largely too soon to tell. When you take an already highly variable phenomenon like rainfall, add in uncertain regional climate change impacts, and factor in the sparse data record, it gets difficult to make a strong case about exactly how the monsoon rainfall is changing.
However, while the effect of warming on the storms is uncertain, temperatures have been increasing. The warming conditions alone can be impactful, drying out soils quicker during breaks in monsoon rainfall, for example.
The recent Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report covers observed and potential future changes in the North American Monsoon. Regarding changes that have already occurred, the report finds modest evidence that the monsoon rainfall has intensified since the 1970s, and this has been partly attributed to greenhouse gas emissions. On the other hand, there is not much agreement among projections for future change in the monsoon, except for regarding the timing—most projections suggest that, under continued climate change, the monsoon will start later in the summer and end later in the fall than it currently does.
What about this year?
It depends where you are! Zack and Mike described this year’s monsoon for southern Arizona as “generational,” meaning once in a generation. It’s not over yet, but possible that the overall monsoon rainfall in Arizona will end up being the highest on record. Some regions have received more than 200% of the average rainfall, and Tucson recorded its wettest month ever this July. On the other hand, New Mexico and northern Mexico are near or a bit below average.
While this will help with the ongoing drought in the southwest, in many regions the precipitation deficit has been building for a long time. The current drought outlooks expect that the drought in Arizona and New Mexico will improve in the short term, but persist.
PIC OF THE WEEK:
The guys on the beach probably thought it was crowded until this gem slipped by unridden. Inevitably they'll paddle out and add to the mayhem, thinking there's a chance...
Keep Surfing,
Michael W. Glenn
Tenacious
Accredited Valentine Man
I Don't Ride Big Waves 'Cause I Have A 100' Minimum
Michael W. Glenn
Tenacious
Accredited Valentine Man
I Don't Ride Big Waves 'Cause I Have A 100' Minimum
