Category: Weather Blog

West Coast Wind Blog: Eddy, 950mb. winds and Bodega

by Mike Godsey,

On this day the WF-WRF barely showed a hint of an eddy. The NAM surface had a better hint. But, as I have noticed again and again for larger elongated eddies, the 950 & 975 NAM do a very good job forecasting existence
of an eddy and its duration.

Also notice how a subtle shift in the eddy location can radically change the wind direction at Bodega. Also notice how such movement made the fog in the Hwy. 92 gap suddenly disappear due to SE winds. Normally such clearing foretells good NW wind at 3rd.

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West Coast Wind Blog: Forecasting UP AND DOWN Gorge winds.

A Slack discussion: Learning to recognize a pattern for very up and down winds in the Columbia River Gorge

by Matt Sounders & Mike Godsey

windfind 4:36 PM

Here is a animation I am working on to help explain the UP AND DOWN winds today.  Even over the ocean at dawn you can see the instablity.

look at all of those vertical strat-cus west of the Cascades

there must be a lot of mid-level cool air

Notice reform clouds on eastern mountains

Luv how the marine layer clouds and wave clouds get wiped out.

they erode and are replaced by that garbage strat-cu

I really like how these animations allow you to review things over and over in motion.

very clearly replacing the cool stable layer with a cool unstable mid-level layer

yeah…these rocking animations are highly useful

Shud try to grab and compare Troutdale 7AM and 7 PM profiler and skew t

that could actually be pretty amusing

now you see the thin inversion…now you don’t!
alas, the models were way overestimating the thickness of the marine inversion on Monday/Tuesday for today so I expected today to be better for longer

very…very-weak top-of-boundary-layer inversion in the morning, then immediately wiped out by steep lapse rates in the midday period

Actually looking at the satellite more closely there was not much of marine layer over Troutdale

it looks very muted even on that profiler chart

what about Portland?
or Astoria

So even at dawn unstable air had moved to Troutdale.

so it would appear. :confused:

You can see it arriving at Astoria

no inversion at all

quite cold at the top of the boundary layer

This would make a good tutorial for Gorge mets. I will grab this conversation and imagery and put into a blog. Then you can add texts. Not all blogs have to be aimed at customers.  We can publish it just for internal use.

modeling as of late Monday had a little bit of an upper ridge over the NW US…instead it’s a little bit of an upper-trough

that makes a large difference

We have to get better at forecasting winds beyond the typical up and down.

new messages

the users are getting a bit savvier and have higher expectations these days
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D-Day Weather

by Meteorologist, Kerry Challoner Anderson

As we recognize the 75th Anniversary of the D-Day invasion it is interesting to look at the role the weather and meteorologists played in the success of the operation. According to How D-Day was Delayed by a Weather Forecast, “The planning team responsible for the invasion of Normandy had to consider the weather, the moon and tides when assigning a date for D-Day. Air Operations required clear skies and a full moon for good visibility. Naval Operations required low winds and calm seas to safely transport troops ashore. Ground troops needed to land at low tide, when German beach obstacles were exposed and easier to deal with.”

Infrared Satellite picture Jun 6, 2019

Seventy-five years ago, the weather conditions were not ideal at the first chance to start but meteorologists forecast a window of improvement so the invasion began on June 6.  Interestingly conditions are quite similar today.  Skies cleared for awhile over the Channel but they didn’t last long and by morning a system rotates up from the south bringing cloudy skies and increasing winds.

Sea Surface Temperature in English Channel, June 2019

One requirement for a successful crossing was visibility but a major issue in the Channel is fog, especially at this time of the year.  Like California the fog forms due to the cold ocean temperatures.   Today’s sea surface temperatures show a very chilly swath of upper 40s and low 50s.  As we move into summer warm, moist air moving over the water is cooled as it comes into contact with the ocean’s surface and advection fog forms.  Once the fog forms it is hard to clear as the air is dense and remains close to the surface unless a storm system moves through with strong enough winds to force the air to mix. But while we need the wind to clear the fog, too much wind would have caused the flotilla to struggle as they crossed the Channel and on the landings. With a front arriving from the south, winds have been increasing today as they likely did 75 years ago.

Wind report from June 6, 2019

As I think about this historical day I give thanks to those who were willing to serve their country, both the fighting men and the meteorologists that provided the forecasts that allowed commanders the ability to plan for the greatest success.

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Kite Surfer Rescue

by Weatherflow Meteorologist, Kerry Challoner Anderson

Last night I was out walking near sunset, checking out the marine layer development north of Santa Cruz, California when I noticed a Kite Surfer struggling to make it back to shore.

The winds were quickly fading as the temperature over the land cooled off.  High pressure over the Pacific had strengthen and moved closer to shore which turned the winds along the California shoreline more northerly.  Consequently the coastal winds were well offshore at Santa Cruz.

Wind speed and direction for the Northern California coast on May 17, 2018

It was interesting to take a look at the observations at this time and see how quickly the wind dropped as the temperature dropped, which showed that the coastal winds were not in play and the only fuel for the Bay winds were sea breezes.  Once the temperature cooled over the land the convection cell vanished and the winds died.

Fortunately rescue crews  arrived just before the light faded to provide assistance back to shore.

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Severe weather in the Northeast

Thunderstorm season in the Northeast US is off to an eye opening start after yesterday’s severe weather outbreak. A strong squall or line of thunderstorms passed through MA down to NJ in the late afternoon and evening bringing damaging winds and localized hail. 



In the radar image below, note the gust front ahead of the thunderstorms and the high dBZ signatures (in purple) over CT as thunderstorms barrel through. Dime to golf ball sized hail was reported in parts of NY and CT.

WeatherFlow stations recorded several gusts around NY and CT exceeding 60 miles per hour!

Honorable Mention: WeatherFlow station, Eaton’s Neck Lighthouse measured a 50 knot gust (~57.5 mph).

Let’s remind ourselves to stay safe when severe weather approaches and heed the watches and warnings issued by your local NWS offices.

This image was taken in Milford, Ma before thunderstorms passed through. These are mammatus clouds, formed by cold dense air sinking downward into warmer air causing groupings of ominous lobes. These types of clouds are often seen out ahead of thunderstorm clouds and are therefore harbingers of imminent severe weather. Source: WF Forecaster Tim Nicholas.

Wind data courtesy of WeatherFlow
College of DuPage:

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Waves arriving from Down Under

by Weatherflow, Meteorologist Kerry Challoner Anderson

A cold outbreak for Eastern Australia has not only meant that I am preparing this from under the warmth of some extra blankets but also has brought record wave heights, epic winds for Wind and Kite Surfers here in Brisbane and the potential for great surf later in the week for Californians.

Forecast minimum temperature for Saturday, May 11, 2018

Usually I am forecasting from my home in California but this week I am back in my childhood home in Australia.  Watching the weather patterns here has been a great reminder of how connected we are in this world especially when it comes to winds and waves.


This past weekend a series of intense storms have pushed down from Antartica across Tasmania, Southern Australia and New Zealand with very strong winds, severe weather and flooding and sending the mass of cooler air across Eastern Australia.

Campbell Island a remote location south of New Zealand recorded winds in excess of 50 mph and a 78 foot wave.

For Eastern Queensland these storms have meant that the “windy westerlies”, as they are called here, were cranking.   These are cold dry winds that blow from the deserts of Central Australia.  I remember them well from my childhood as we are pretty thin-skinned here and so it meant for a cold day on the playground.  I enjoyed being here for a Westerlies event as they also mean some epic wind conditions wind surfers and kiters at Wellington Point.

Here’s a shout out to our mates down under.  It was great to visit and find out how you use our data and models.

And Californians surfers should benefit from all this energy down under. Waves models show that this energy travels across the Pacific and will arrive in California later in the week.

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Picking the Right Model

Yesterday’s forecast was a tough one so I made sure to check back this evening to verify.  We know we may not always be exactly right and so the process of verifying helps us to learn and improve and also to understand the eccentricities of each model.  WeatherFlow has a suite of models to chose from, each having its own strengths and weaknesses.

As I looked through this event of strong NNW flow spilling over the mountains of Southern California it was interesting to see how each model responded.  It became very clear how valuable a fine mesh model is when forecasting winds in this terrain.

Here is how the winds looked at 9pm.  Belmont has seen over 30 knots for much of today while just a few miles west Cabrillo’s winds have been more northerly and lighter, in the upper teens to low 20s.

NAM 12km Forecast Model 8pm, 4/12/2018

The map above shows the forecast for the Long Beach area as predicted by the North American Model using a 12 km grid while the map below shows the same model but using a 3 km grid.  You can clearly see that the smaller grid is able to predict the strong winds that are created as the NNW flow pushes through the LA Basin and then offshore south of Cabrillo.  However it is clear that the 30 knot winds for Belmont are not predicted.


NAM 3km Model 8pm, 3/12/2018

While the NAM 3 obviously did a much better job than it’s 12 km counterpart, it was interesting to see the output from WeatherFlow’s Wf-Wrf which was run on a 1km grid.  The map below shows that this model picked up on the both the higher speeds and the wide variation due in large part to the higher resolution of the grid.

WeatherFlow Wf-Wrf 1km Forecast Model 8pm 4/12/2018


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