West Coast Wind Blog: Long battered by storms passing to the north…

North Pacific High lords over the
Pacific this Sunday!

by Mike Godsey

mike@iwindsurf.com

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.

Posted in Columbia River Gorge, Los Angeles, San Diego, San Francisco

West Coast Wind Blog: Waiting for the return of strong NW winds…

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.

Posted in Los Angeles, San Diego, San Francisco

Strong cold front blasts Rockies. Now heads to the Plains with Severe Weather.

by Meteorologist
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.

 

 

Posted in Weather Blog

West Coast Wind Blog: North Pacific High crushed and departing…

No, this is not the title of a romance novel but rather it explains the coming
weak wind weekend.

by Mike Godsey

So after today, Friday 14 the S. F. Bay Area and Southern California will see weak winds while the Gorge has a few days of glorious weather. (Should have said the Gorge was windless, clear and warm in the East and Corridor since high pressure inland means strong E. winds for Rooster.)

Often after the Bay Area and Southern California have had strong NW winds the forecasts will talk about a storm “crushing” the NPH against the coast and the winds building for one day only to die for several days. Usually these forecasts mention the North Pacific High “shrinking and departing our waters” While at the same time unfavorable NE winds develop in the AM.

To help you visualize all of this I have annotate this animation with isobars of high pressure in red/orange tones and the isobars of low pressure in the blue/purple colors. Note the time stamp at the bottom of the imagery.

Starting Friday morning you can see the major players: A small North Pacific High delivering NW wind to the California coast. Then check out the storm system moving in from the west. Also check out the storm almost off the image near Vancouver Island. Together these lows encourage the NPH to push a high pressure ridge towards the Gorge.

In the subsequent frames notice how this high pressure ridge (in red) moves inland. This creates warmer clearer weather in the Gorge but it also creates mild NE flow in the California interior. This in turn makes it a bit more difficult for the ocean winds to reach into the Bay.

As the frames go by notice how the NPH becomes crushed against the California coast and the NW winds (indicated by the stream lines) turn more NNW and  weaken. Finally the NPH is crushed into 2 parts. The northern part moves over the Gorge so there will great but windless weather there this weekend since the pressure gradient will be zilch. While the southern part of the NPH moves off Baja. This leaves California with only weak winds for the weekend.

Lastly notice the hint of a new North Pacific High forming towards Hawaii. At this time time it is not clear when this high pressure will move towards the California coast.

Posted in Columbia River Gorge, Los Angeles, San Diego, San Francisco

West Coast Wind Blog: A quick look at SW storm winds turning into…

NW clearing winds: a visual tour.

by Mike Godsey

 

Posted in Los Angeles, San Diego, San Francisco

West Coast Wind Blog: Color satellite view of:

Big NW clearing winds for Southern California.

by Mike Godsey

As you saw in the blog below Southern California had the perfect setup for strong NW winds this weekend. Lots of upper teens to low 20’s or even stronger. Here is a satellite image of what that type of blow looks like:

West Coast Wind Blog: Anatomy of a Southern California…

Posted in Los Angeles, San Diego

West Coast Wind Blog: Anatomy of a Southern California…

Strong wind day on the coast

by Mike Godsey

If you look at the iwindsurf.com/ikitesurf.com/sailflow.com wind maps this afternoon for the S.F. Bay Area or Southern California you will be struck by how weak the winds are today. Yesterday a potent storm crashed into Northern California and even today both the Bay Area and Southern California are seeing weak southerly storm winds from this low pressure. While the Oregon coast is being battered by southerly winds in the upper 20’s to upper 40’s. You can see this happening in the Friday frames of the animation.

Looking at this first animation you can see the remains of the storms center in the Friday frames. Note how the counter-clockwise spinning winds spiraling out of the storm Friday are hitting the entire California coast and even roar over the Great Basin.

Each advancing frame jumps a few  hours in this animation. So notice the “old” North Pacific High west of Baja fading away. More importantly notice the small “new” North Pacific High far to the west of Southern California. Notice the clockwise winds spiraling outward from this high pressure.  As the storm departs the new NPH lunges towards the coast as you can see in the Saturday frames. Notice how the North Pacific High’s surface NW winds move closer to the Southern California coast Saturday morning.

Then in the afternoon notice how the winds going from Southern California to the Great Basin and towards Las Vegas really crank up.

This same pressure gradient also causes the North Pacific High’s surface NW winds to curve from NW to WNW or even W in the afternoon Saturday.

So a combo of the NPH’s NW wind and a strong pressure gradient to the Southern California deserts, Great Basin and Las Vegas should make for upper teens to mild low 20’s wind along the Southern California coast Saturday. But I expect gusts stronger than that? Why?

The next animation show the winds at 2000 feet above Southern California Friday through Saturday. First watch the time scale at the bottom of the image.

Note how today, Friday April 7, weak storm winds prevail over the Southern California bight and on the coast. Notice how the strong SW storm winds are focused well inland.

Now glance back at the North Pacific High’s surface NW winds in the TOP image. Rather than visualizing the NPH as a circle of clockwise wind picture it a 3D dome of high pressure with the winds spiraling out clockwise from the surface to several thousand feet high. And since the winds just aloft do not encounter friction from the sea or land they are stronger than the surface wind. Saturday these winds aloft are almost perfectly aligned with the NPH’s surface winds so they transfer a bit of momentum to the surface. So my actual forecast will be for brief locally stronger gusts over the upper teens to low 20’s forecast.

Remember this is a dissection of the details of an event that has yet to happen. There is always a chance I could be doing an autopsy of a failed forecast this weekend!

Posted in Columbia River Gorge, Los Angeles, San Diego, San Francisco

West Coast Wind Blog: Strong North Pacific High but low quality wind because of…

Pesky surface ridge and passing storms.

Part one.

by Mike Godsey

“When do we get rid of the North Wind in the Bay area?

How about a little blog on this?” C. Jutkins

I have received a good number of e-mails like this the last week or so. If you kite or sail in the East Bay or Sherman Island you know exactly what C. is talking about. And if your home venue is at even normally reliable sites like Waddell and 3rd. you have experienced a number of weird days recently.

For example take a look at the Waddell wind graph for Waddell. Notice the unusual UP AND DOWN winds. Or the strange 3rd. Ave. graph with the winds much stronger in the morning than in the afternoon. Or the Berkeley graph with strange wind shifts and up and down velocities. And even normally trust worthy Bodega with over 20 knots difference between the lulls and the just. And the Sherman Island wind graph is so pathetic that I won’t bother putting a graph with endless weak northerly winds. So what is going on with our wind.

March is always fickle wind wise. Some years the North Pacific High’s surface NW winds are roaring along the coast after the passage of each storm and sails and kites are stretched by powerful wind.

Other years the North Pacific High’s surface NW winds are largely absent and there are few windy coast and Peninsula days.

But this year we have had almost endless strong winds from the North Pacific High but the quality of the wind on the coast and inside the Bay has often been poor.

At a quick look the model projection to the left looks very promising. The Red areas in the map represent low to mid 20’s wind. So it looks like Waddell, Coyote and 3rd. Ave. should rip.

But look at the area off the coast inside the left white diamond. Notice the weird waves of powerful wind interspersed with mild winds. Now look at the white diamond inside the Bay Area. Because of turbulence induced by topography the waves are not as clear but you  can see strong and light wind areas intermingled. You can easily image how you would experience these wind pattens on the water. But the question arises… what is causing all this up and down action?

The next image gives you a clue. First find the huge dome of high pressure air known as the North Pacific High. Note the clockwise wind flow spiraling out from this surface high pressure. Note how the NPH is sending NW wind to Southern California but the wind near the Bay Area is more NNW. This is an issue since wind has to curve in the Bay Area to bring winds to sites inside the Bay Area. And clearly is NW makes the curve easier than NNW wind.

Now look carefully at the wind flow just to the north of the Bay Area. Notice how it is N. to NNE flow. as wind comes down the Central Valley. Now picture NNW ocean wind trying to curve into the Bay Area and the effect of NNE wind on this curving. You can easily visualize that this NNE winds will tend to divert or weaken the westerly wind moving into the Bay. Most of the time the NNE surface flow fades away mid day so it does impact our sailing wind.

But why NNE flow coming down the Central Valley? Look again at the NPH. Notice how this mountain of high pressure air has pushed an extension or ridge over far Northern California. Notice how results in N. coast wind in that area. And as the ridge extends over the land the wind flow is disrupted and weakened over the coast range but becomes NE wind in the Central Valley then heads towards the Bay Area. So NNW to NE flow occurs when the North Pacific High form a ridge. Look carefully and you can see that this ridge shape has also caused the winds at the Bay Area ocean buoys to be more NNW rather than the more typical and favorable NW.

But there is another factor that has been messing with our winds. Even if the NNW to NNE surface winds coming from the Central Valley fades mid day there are still strong NNW to NNE winds just aloft that often continue all day.

In this next image note the elevation above the surface scale on the right side of the image.

Note the strong NW surface winds at 3-4PM west of the Bay Area and how those winds curve into the Bay as WNW to W wind.

Now watch as we jump in elevation from the surface to 975 mb level which averages about 1000 feet in elevation. Notice how the winds inside the Bay are still WNW to W.

Now watch as we jump to the 925 mb level which is at about 2500 feet in elevation. Wow! At that level we still have NNE winds. And as those wind interact with the North Bay and East Bay coast range they become turbulent and randomly impact the strength and direction of the surface winds hitting your kite or sail. This accounts for the huge gusts and lulls you saw in the wind graphs below and in the model output in the second image.

That is enough for one blog but… we are still left with one question? What causes the North Pacific High to develop this ridge that in turn creates the NNW to NE surface wind and wind aloft. So stay tuned for the 2nd part of this blog. Mike.

 

 

Posted in San Francisco

West Coast Wind Blog: Far afield for a quick look at…

Super Cyclone Debbie

by Mike Godsey,

Pretty windy in much of the S. F. Bay Area today. But Kerry, one of the Weatherflow Bay Area meteorologist, has family near Airlee Beach Australia and it is really windy in that area today as super cyclone Debbie kept the nearest sensor above 100 knots. Here is some imagery from Debbie.

Posted in Cape Cod, Chesapeake Bay, Coastal Georgia, Coastal South Carolina, Columbia River Gorge, Connecticut, Delmarva, Long Island/SE New York, Long Island/SE NY, Los Angeles, Massachusetts North Coast, Ontario- Simcoe, Ontario: Lake Erie, Ontario: Lake Ontario, Outer Banks of North Carolina, Rhode Island, San Diego, San Francisco, SouthEastern North Carolina, Tidewater Virginia

Watching the Tropics in March Already.

By WeatherFlow meteorlogist Shea Gibson.

There is a bit of a pre-season area of disturbance to be watching for in the tropical Atlantic basin…

We are watching this area for Sunday through Tuesday in the western Atlantic as models are coming into more and more agreement for possible tropical activity. The area in question has a good chance at becoming a surface Low feature over warm waters, but looks to eventually move over cooler waters. This would give it a subtropical signature as the surface low develops and heads NE/ENE in time. Either way, the SE coastal region may get a small bump in swell heights and Bermuda should watch for moderate to fresh gales.

GFS forecast for Monday at 2AM.

ECMWF (Euro) forecast for Tues 8AM EDT (12PM UTC)

 Using NCEP, CMC (Canadian) and  ECMWF (EURO) ensembles for chance of tropical cyclone genesis, here is the latest:
And here are the current Sea Surface Temps with the area shown in the blue box. Notice the cooler waters towards the NE quadrant of the box.
This is a reminder that pre-season systems are possible as we head into our warmer season, so it’s time to shake off the dust and oil the tropical bookmarks. We aren’t expecting a named system out of this, but Subtropical Storm “Arlene” would be the most likely scenario if it does strengthen.

Cheers,

Shea Gibson
WeatherFlow Meteorologist/Wind Forecaster
Outreach & New Station Projects
SE Region/East Coast
Twitter: @WeatherFlowCHAS

Sources: NASA Sport SST,  Tropical Tidbits, Hurricane Forecast Improvement Program- NOAA 

Posted in Coastal Georgia, Coastal South Carolina, Outer Banks of North Carolina, SouthEastern North Carolina