Huge North Pacific High dominates the pacific.
by Mike Godsey
Nice marine surge and SW flow underway today! Remember when that used to happen in July?
In the top image today (below) you can see the SW flow over the Bay Area that is jazzing up the marine surge. But I want you to focus on the wimpy North Pacific High north of Hawaii in that same image. Note the clockwise rotation of wind around the high and the NW winds far far away from California. Also note the storm WNW of the Pacific Northwest that is keeping the NPH away from our coast.
Now look at the second image of the North Pacific High as modeled for this Saturday. The NPH totally dominates the Pacific from the Gulf of Alaska to Hawaii to California to Baja. This should mean building NW winds towards this weekend.
by WeatherFlow meteorologist Shea Gibson
Ever wonder when you are at the beach that all of a sudden winds seem to come out of nowhere on a perfectly sunny day?
Well, the land-sea interface of the SE Region is a very sensitive atmospheric environment and has a few tricks up its sleeve. One of them is the “Sea Breeze”, which tends to be the dominant feature that shows the push and pull of land-based heat fluxing versus the cool-water based cold front formation moving onto shore. When we have large areas of High pressure over the Atlantic (in many cases a “Bermuda High”), we see a much more pronounced Southerly flow that increases – especially in the warmer months. Other times, these Southerly Sea Breezes will occur if the “other” variant dominant wind fades out and High pressure develops closer to the coast on a smaller scale. More about Sea Breeze basics in my blog here: http://blog.weatherflow.com/sea-breezes-in-the-southeast-region-part-i-basic-understanding/
NOTE: The term “Coastal Carolina Ridge” or “default coastal ridge” is just a general term used to describe an event that occurs naturally along the curvature of the GA/SC border coastline climate when one dominant feature runs its course, and then the typical Sea Breeze feature takes over (either for a small period or for the remainder of the day or night). In this case, was just a smaller period event, but definitely worth noting.
This event on Sunday, May 7th during the afternoon hours shows what happens when background winds (in this case Westerly winds) fall below a certain point while fading quickly as they head offshore.
Just another one of those tricky nuances along the coast we constantly watch for in our forecast efforts. Stay safe all!
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Westerly winds for the Gorge!
by Mike Godsey
So do you have a boss? Someone who rules a small part of your life? Well if you are a Gorge, California, Hawaiian or Baja kiter or windsurfer the real boss is 2500 miles wide, thousands of feet deep and rules the north pacific in the spring and summer. The real boss in the North Pacific High which is the major factor in propelling sails and kites much of the year.
Check out the “the boss” and its clockwise spinning winds in this imagery. Note how it extends from the Canada to Baja to Hawaii. Sorta dwarfs your other bosses huh?
And today if Benjamin’s Gorge forecast is right the boss is going to press high pressure air against the entire west coast. This should create a solid pressure gradient and strong winds from the Gorge to Jalama. The forecast is a bit tricky for the Gorge since the air mass is unstable and wet which makes it hard for the wind to stick to the surface. So sites further away from topography will probably be more reliable.
Wimpy marine surge retreats and the North Pacific High lords over the pacific!
by Mike Godsey, email@example.com
Doesn’t it drive you crazy? So often our forecasts prattle on about weather events happening hundreds or even thousands of miles away or hundreds or thousands of feet aloft. Yet you don’t even care what is happening at sites across the Bay. Your focus is on the possible winds at your favorite sites and who cares about what is happening aloft or far away!
So the intent of this blog is to give you one example of why those distant events are important in shaping the wind at your launch site.
Looking at the first animation for today Thursday May 4 you can see that we are in an atypical marine surge pattern with wimpy NW winds at the ocean buoys and W to WSW flow for most of the Bay Area today.
But the big story that will determine your kite or sail size tomorrow is taking shape almost 1000 miles to the WNW and about ≈ 18,000 ft. feet aloft over the pacific.
Up at the 500 mb. level an upper ridge is steering a surface North Pacific High towards the west coast with an ETA of Friday morning.
Looking at the second animation you can see that below this upper ridge a huge but distant NPH marches towards the west coast and our present weak NW winds ramp up fast by Friday afternoon.
So if our forecasts just focused on events like you see in the first animation we would not have a clue about the much stronger NW winds coming tomorrow. And we would not be able to give you a heads up so you can begin planning your Friday.
And if you live in the Gorge the heat wave ends and as the North Pacific High moves towards the west coast it builds up a pressure gradient the brings gusty westerly winds to many Gorge sites.
…As the North Pacific High takes an extended early spring vacation to the south.
by Mike Godsey
Compare the wind graphs for Waddell, normally one of the windiest spring sites in the Bay Area with Leo in Southern California. Notice have about the same number of windy days. Typically Waddell would have many more strong NW days and Leo, at least in recent years, would have fewer.
This spring the Southern California coast has the most consistent strong NW winds in quite a while. Meanwhile the San Francisco Bay Area’s coast and Peninsula, which usually see strong NW clearing winds in the spring, have had lots of limp days. While up near the Gorge the National Weather Service says Portland has experienced the most wet days in recorded history with 145 days of rain so far this winter and more rain coming. So what is happening?
Looking at the first animation of the Surface Winds notice that the North Pacific High is centered almost due WSW of Southern California. Now NPH is always being bounced around the pacific but its average April location is further southward this year. And looking at the animation you can see this focuses the strongest NW wind in the Southern California area. Now notice the storm off the Pacific Northwest and the southerly winds north of the S. F. Bay Area. The southerly storm track that brought so much rain to California this winter continues this spring. And this in turn is often keeping the NPH in Southern California waters as well as keeping the Pacific Northwest wet.
So what is causing this more southerly locale for the NPH? Watch the animation as it jumps from the surface winds to the winds at the 500mb level ≈ 18,000 ft. Notice the upper ridges and upper troughs that act to steer storm systems and impact the position of the North Pacific High. This winter and spring these upper ridges and upper troughs extended more south and more north than the historical norm. This in turn promotes a more southerly storm track and slower changes in the weather. And this in turn has kept the NPH’s average location south of the Bay Area benefiting Southern California winds and keeping the Pacific Northwest wet.
Year around there is almost always a North Pacific High located in the north pacific. But the North Pacific High waxes and wanes in size and its location shifts from south to north with the seasons. It is normally difficult to visualize this because the NPH is also bounced around and expands and shrinks with the passage of upper troughs and ridge way aloft. So to help you visualize this I have annotated an animation that shows the AVERAGE location of the North Pacific High month to month as averaged over 21 years. By averaging this data the day to day and week to week movements of the North Pacific High disappear and we can see the SEASONAL changes in the North Pacific High.
Looking at the animation most obvious movement of the North Pacific High with the seasons is its movement northward in the spring and it’s enlarging size. Also notice how the NPH shrinks in the fall and moves southward.
This year the North Pacific High has been slower than average in moving northward hence the Southern California, Bay Area and Pacific Northwest wind and weather pattern. Can you guess what this has meant for San Carlos, Baja Norte. In the next blog I will look at the migration of the North Pacific High in more detail. But remember that despite the North Pacific High’s southerly average location this spring it will invariable move into Bay Area waters as the days pass. Indeed I expect it to reach the Bay…. today April 27.
A quick look at one of the factors that makes Santa Barbara to Ventura wind forecasting so difficult.
by Mike Godsey
One of the variables that makes forecasting wind in the Isla Vista to Ventura Southern California zone is the Mid Channel eddy off Santa Barbara. This eddy may form when there the ocean wind west of Pismo Beach is NW and especially NNW. Today, April 23 at 8:48AM you can see this eddy as the counter-clockwise spinning mass of air south of Santa Barbara.
Notice that there are strong NW winds off of Jalama and near the Channel Islands. Some of this NW wind heads into the valley near Santa Maria along the Hwy. 101 corridor. Hitting the mountains north of Santa Barbara and Isla Vista this wind lifts crests the ridges, acceleratesthen roars down the canyons as you can see in the sensor reading circled in green.
As the descends it warms and creates a low pressure area near shore. This low pressure helps cause some of the weaker NW winds just offshore to turn towards the low pressure creating the eddy you can see in the sensor data. At the same time the high velocity NW wind further offshore creates wind shear with the slower moving inshore air which also encourages eddy formation.
As long as this eddy situation prevails the NW winds just offshore are unlikely to reach the Isla Vista or Ledbetter beaches. Today it looks like the eddy will endure to mid afternoon. This is why I am forecasting lighter winds for Santa Barbara.
Also noice how Ventura’s C St. is on the edge of the wind blocking eddy. This makes C St. especially difficult to forecast today. If the eddy dies early then C St. could really blow strong today. At present I am forecasting LATE upper teens wind there. Standby for reality…
North Pacific High lords over the
Pacific this Sunday!
by Mike Godsey
This first animation from the blog I posted last Sunday shows the North Pacific High taking a beating from a succession of wintry storms NW of the California coast.
So for the most part Northern California has seen weak winds since then. In the animation notice how the old North Pacific High is shoved southward while a “new” North Pacific High struggles to reach the Northern California coast. Note how it does reach Southern California waters but the S. F. Bay Area stays on the edge of the North Pacific High’s surface NW winds today April 20.
Now let’s look at the 2nd animation which covers from today, Thursday April 20 to next Monday April 24.
Notice how the animation for today shows only a sliver of the old North Pacific High near the Bay Area while more of the NW wind is in Southern California waters.
This is due to the presence of the large storm you see in the N. pacific.
Also note another “new” North Pacific High is forming north of Hawaii. Watch as this new NPH moves towards the west coast as the storm exits to the NE.
So I expect building winds for Southern California and Northern California on Sunday April 23.
The plight of the North Pacific High
by Mike Godsey
It happens every spring. After days of useful NW wind curving into the Southern California and Bay Area coastal windsurfing and kiting sites we enter a long wind drought.
At these times wind users may almost feel like buzzards as they await the return of their prey… wind!
The most obvious cause is the passage of storms but why is it that the fabled NW clearing winds do not redeploy after these storms? This animation will help see the issue.
Notice how close one storm follow the previous storm. This acts to keep the North Pacific High far SW of the California coast. Finally about next Thursday it makes a lunge to our coast.
Kerry Challoner Anderson
In our forecasts we frequently discuss the temperature variations across the forecast area and how these contrasting mini air masses will create the winds most of our customers are looking for. Yesterday the Rocky Mountains felt the effects on a much larger scale as two large and very different air masses collided along a front that was moving east bound.
At high elevations wind gusts of over 60 mph were registered at Alta Ski Resort while in the valleys thousands of customers were left without power in the Greater Salt Lake area well into the evening. Large trees were toppled as was this fence.
The long period of sustained winds left neighbors searching for their backyard items.
Facebook posts from neighbors trying to locate their backyard items.
What’s next for this system. By early morning the front was heading eastward into Colorado and into the Plains. This is the perfect set up for and timing for severe weather. So keep a close watch on the forecasts if you live in these areas.
Friday April 14,2017 2am ET.