Where did our warm water go?!
SURF:
Had a little SW this past week. Nothing exciting but it kept far north SD county in rideable chest high waves and head high sets in the OC. We had a new little S fill in last night and today we've got shoulder high sets again with head high sets for the Vans US Open in HB. That lasts into Saturday. All in all should be a fun little weekend of surf if the clouds ever decide to burn off. Note there's only a tiny NW windswell in the water so the surf will be a little lined up this weekend- especially with the early morning low tide. So make sure to surf a point, jetty, or reef.
FORECAST:
After a little weekend of surf, we get some waist high NW windswell filling in late Monday. That lasts into Tuesday- just in time for a good SW swell on the charts.
WEATHER:
Looks like a carbon copy of last weekend: Monsoonal moisture is coming in from the desert southwest and there's a chance of showers here at the coast and stronger storms in the mountain and deserts. After the weekend we've got a weak cold front moving through northern CA towards Monday so it will clear out the monsoon moisture as well as help scour out the low clouds/fog during the afternoons along the coast. That pattern should hold the rest of next week and temps will be in the mid-70's along the beaches.
BEST BET:
Tuesday looks pretty good if the forecast holds up: Sunny skies by mid-day, a new head high SW swell, and a waist high NW swell to peak up the beachbreaks.
NEWS OF THE WEEK:
Why do such strong storms form in the central plains of the U.S. but seemingly not in southern California? Could their violent tornadoes happen here? The National Oceanic and Atmospheric Administration aims to explain the phenomenon and why get waterspouts here. First up: The geography of the Central U.S. plays a large role in the formation of severe weather, including tornadoes. Low-level southerly winds bring up warm, moist air from the Gulf of Mexico, while higher up in the atmosphere cool, dry air moves in from the west. The warm, moist, lower density air topped by cooler, drier, higher density air causes the atmosphere to become unstable, meaning the air wants to rise rapidly. One index commonly used to describe the atmospheric in-stability is called CAPE – or Convective Available Potential Energy. The higher the CAPE, the more unstable the air is. In the Plains and Southeast, the CAPE can exceed 5,000 Joules per kilogram. In California, by contrast, 500 J/kg is considered high! It is the instability that allows air to rise and thunder-storms to develop, but that alone is not enough for tornadoes to form. Another major ingredient is wind shear: the change in wind direction and/or speed with height. South winds associated with the low-level jet (usually strongest around 5,000 feet above sea level) can be as high as 50-60 mph! This is the same jet that brings in that oppressively muggy air from the Gulf of Mexico. If you’ve ever experienced a dew point of 75, you know it makes our marine layer feel as dry as a Santa Ana wind. With a mid-level trough (around 20,000 feet above sea level) to the west, the winds become more westerly. Even higher up in the atmosphere, near 40,000 feet above sea level, the winds can exceed 100 mph. To put things in perspective, on the afternoon of May 31, 2013, near the time of the devastating 2.6 mile wide Moore, OK tornado, the winds at 5,000 feet were south at 41 mph, the winds at 19,000 feet were southwest at 61 mph, and at 30,000 feet they were southwest at 83 mph. The CAPE was 3,018 J/kg. This change in wind speed and direction with height causes storms to rotate, but not all rotating storms – commonly referred to as supercells – produce tornadoes. In fact, it is not well understood why some supercells produce tornadoes while many others do not. We do know you need strong directional wind shear in the low-levels, generally within the lowest 3,000 feet. This is where other surface features, such as fronts and drylines, come into play. Along these boundaries, the surface winds may shift to the southeast or even east. Now the winds are changing from southeast, to south, to southwest with height. The last piece of the puzzle is some sort of forcing to initiate storms. This can be something as simple as the sun heating up the ground and air near the surface, but in severe weather outbreaks it’s usually in the form of an upper level trough moving in and/or a frontal passage. Sometimes you can have everything in place – tons of instability, shear, and surface boundaries galore – and you will see nothing but sad little cumulus clouds because a layer of very stable air lingers somewhere in the atmosphere, preventing the air from rising and crushing your dreams of seeing a beautiful thunderstorm. To severe weather forecasters and storm chasers alike, there is nothing more humbling (and disappointing) than a clear air bust. California has experienced tornadic super-cells. However, they tend to be much smaller and weaker than their counterparts further east. In March 2003, one such storm passed north of the NWS office in Rancho Bernardo and produced a weak tornado in Ramona. Why are these storms so much less common and weaker here? First, the instability is much weaker here due to the lack of that special mixture of warm, very humid air near the surface and much cooler, drier air aloft. Even with a surge of subtropical moisture during the monsoon, our CAPE is not nearly as high as it gets in the plains. Wind shear tends to be strongest here with winter storms, usually ahead of a cold front. On Jan 19, 2010, strong southerly low-level winds ahead of a cold front, along with good instability (by CA standards), led to a tornado in Huntington Beach. Winds (and therefore wind shear) tend to be weak when the weather pattern is favorable for monsoon thunderstorms. In short, during the winter we may have the winds, but lack the instability. During the summer, we may have the instability, but lack the winds. We just can’t seem to get that combination of high instability and high shear needed for massive supercells at the same time! But wait, how do we get those tornadoes in the Inland Empire and deserts? What about the waterspouts off the coast? Those tornadoes form through a different mechanism, one that does not require such a delicate balance of shear, instability, and forcing. These tornadoes, known as landspouts, form in regions where air at the surface is colliding. In Southern California, this is usually along a sea breeze convergence zone. In the Inland Empire, the sea breeze moves around the Santa Ana Mountains and into the IE from the west and south. Where they meet in the middle is known as the Elsinore Convergence Zone (ECZ). This boundary usually extends from the Hemet/San Jacinto area to Lake Elsinore. As the two sea breezes crash into each other, the air is forced upward. If there is sufficient moisture and instability, showers and thunderstorms may form along the ECZ. Occasionally, the convergence can cause a circulation to form at the surface. If this circulation lines up with the upward motion, a landspout will form. Another form of tornadoes, called gustnadoes, may form along the leading edge of outflow from these thunderstorms. The mechanism for gustnadoes is similar to landspouts, except the convergence is along the outflow boundary instead of colliding sea breezes. Both tend to be weak – usually EF-0 or EF-1 – but are still enough to do damage. Similar convergence zones set up in the deserts. Waterspouts are essentially landspouts, but over water. Most commonly, waterspouts result from circulations in the convergence bands in the lee of the islands, or from circulations on convergence bands created when the onshore flow is partially blocked by terrain. Island banding occurs when air flows around the islands, including Catalina and San Clemente, and crashes into each other on the opposite side. Where there is convergence, there is upward motion, as well as low-level circulations. Where the two overlap – BOOM! – waterspout.
BEST OF THE BLOG:
3 new clips to get the adrenaline flowing for the weekend sesh: River surfing, Coleborn ripping, and a Kerama's recap. All of that and more, plus an in depth THE Surf Report in the blog below!
PIC OF THE WEEK:
When your bros tell you it was firing, this is what they mean. For more en fuego photos, check out Andrew Shield's work here.
Keep Surfing,
Michael W. Glenn
Kinda Funky
George Alexander Louis's Godfather
The Inspiration For Maui And Son's Sharkman
