A Cool Month, But Lots of Sun in Our Future

November is usually a wet month in the Northwest, but the first 2-3 weeks of October are often quite decent.  And some exceptionally nice weather is ahead of us this week.

The last 30 days have been cooler than normal over the Northwest (see image), with Montana being absolutely frigid for this time of the year.  The southwest interior was warmer than normal.

Precipitation was near normal for most of the West, except moister than normal in western Washington and in hurricane-ravaged Arizona (Hurricane Rosa).

Today was a drippy day, but wait until things change tomorrow, with major ridging (high pressure) over the region.  Buy some suntan lotion, you will need it.

Let me illustrate with some upper-level (500-hPa) charts.  Today at 8 PM, a major ridge is offshore, but a weak trough is moving over us, bringing clouds and light showers.

By 2 AM Wednesday, the ridge is moving towards us, resulting in a drying transition.

 Thursday at 5 AM, the ridge pushes over us, bringing warming and no precipitation.

 And by Saturday at 2 PM, a huge ridge over the coast.

 And even more so at 11 PM Sunday.

Looking at the National Weather Service GEFS ensembles (running many forecasts), the rain will be over by tomorrow AM:

And temperatures will steadily climb--to near 70F by this weekend!

This weekend will be perfect for a fall hike, a bike ride, or like me, the Dawg Dash on Sunday at the UW.  My little dog LOVES the dog dash, a fun run that helps support scholarships at the UW.    Perfect fall weather and the leaves are starting to turn.  This is why we live here rather than in arid, weather boring places like San Diego.

from Cliff Mass Weather and Climate Blog https://ift.tt/2QEjGbE

Do Wind Turbines Enhance Global Warming? No!

There were a series of headlines in a variety of media outlets this week suggesting an unfounded and unphysical claim:  that wind turbines might contribute to global warming.  Some examples below:

The Associated Press

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The Harvard Gazette

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MIT Review

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These stories are based on an article entitled “Climate Impacts of Windpower,” by Dr. David Keith and Dr. Lee Miller, in which they ran the WRF model (the one I use) and added the impacts of a very large number of wind turbines over the central U.S.  They found that the wind turbines caused a .24C warming over the U.S. due to the mixing of warm air down to the surface.

Now why does mixing of the wind in the vertical produce surface warming?  Doesn't temperature cool with height?

The key issue is that frequently the surface is cooler than than the air above.  This is particularly true at night when the earth radiates heat to space more effectively than the air above.  In these cases we can get an inversion, air warming with height.  Mixing due to the disturbance of the air flow by the spinning blades can mix warmer air to the surface.

This effect is no stranger here in the Northwest--have you seen the fans around orchards in eastern Washington?  They are used to mix warmer air down to the surface to reduce freezing temperatures when the buds on fruit trees are vulnerable.  Some vineyards have them as well.

 "Orchard-Rite" Wind Machines

So one can cause small net localized warming at the surface by mixing the low-level air, but you are NOT warming the atmosphere as a whole, but simply moving warm air around. 

Thus, wind turbines are not producing any net heating to the atmosphere and thus doing NOTHING to lessen global warming.   And the only time there is doing localized warming is when the surface is relatively cool!

Wind energy is am important technology in our quest to move towards renewable energy and a potent complement to solar energy,  particular at night and in cloudy regions.   It is unfortunate that some careless media reporting left an inaccurate impression of negative climate impacts of wind energy.

from Cliff Mass Weather and Climate Blog https://ift.tt/2C2wG6Q

Do Wind Turbines Enhance Global Warming? No!

There were a series of headlines in a variety of media outlets this week suggesting an unfounded and unphysical claim:  that wind turbines might contribute to global warming.  Some examples below:

The Associated Press

____________________________________________________________

The Harvard Gazette

 __________________________________________________________________

MIT Review

_______________________________________________________________________

These stories are based on an article entitled “Climate Impacts of Windpower,” by Dr. David Keith and Dr. Lee Miller, in which they ran the WRF model (the one I use) and added the impacts of a very large number of wind turbines over the central U.S.  They found that the wind turbines caused a .24C warming over the U.S. due to the mixing of warm air down to the surface.

Now why does mixing of the wind in the vertical produce surface warming?  Doesn't temperature cool with height?

The key issue is that frequently the surface is cooler than than the air above.  This is particularly true at night when the earth radiates heat to space more effectively than the air above.  In these cases we can get an inversion, air warming with height.  Mixing due to the disturbance of the air flow by the spinning blades can mix warmer air to the surface.

This effect is no stranger here in the Northwest--have you seen the fans around orchards in eastern Washington?  They are used to mix warmer air down to the surface to reduce freezing temperatures when the buds on fruit trees are vulnerable.  Some vineyards have them as well.

 "Orchard-Rite" Wind Machines

So one can cause small net localized warming at the surface by mixing the low-level air, but you are NOT warming the atmosphere as a whole, but simply moving warm air around. 

Thus, wind turbines are not producing any net heating to the atmosphere and thus doing NOTHING to lessen global warming.   And the only time there is doing localized warming is when the surface is relatively cool!

Wind energy is am important technology in our quest to move towards renewable energy and a potent complement to solar energy,  particular at night and in cloudy regions.   It is unfortunate that some careless media reporting left an inaccurate impression of negative climate impacts of wind energy.

from Cliff Mass Weather and Climate Blog https://ift.tt/2C2wG6Q

Land Breeze Clouds

This morning I was at an early meeting at the UW, looking out towards the West and I saw a line of low-level clouds and I recognized their origin.... clouds over the Sound produced by converging land breezes from both shores.

Here is a satellite image this AM over northern Puget Sound...you see the line of clouds?

And there was an even better line in the center of the Strait of Georgia (see below)

This lines were produced by land breezes, the movement of air form land to water, which occur when land is cooler than adjacent water surfaces.

The low temperatures this morning (below) shows temperatures dropping into the 30sF over Vancouver Island and southern BC, while the water temperatures were around 50F, and the a number of the marine stations reported mid to upper 40s.  As as result,  land breezes formed on both shores and then collided over the central Strait of Georgia, forcing rising motion and clouds.

This figures illustrates what is happening:

A similar, but weaker, situation occurred over northern Puget Sound, with low 40s over land and low 50s over water.

No land breeze clouds tomorrow...a wet weather system is approaching!

from Cliff Mass Weather and Climate Blog https://ift.tt/2PjTthW

Land Breeze Clouds

This morning I was at an early meeting at the UW, looking out towards the West and I saw a line of low-level clouds and I recognized their origin.... clouds over the Sound produced by converging land breezes from both shores.

Here is a satellite image this AM over northern Puget Sound...you see the line of clouds?

And there was an even better line in the center of the Strait of Georgia (see below)

This lines were produced by land breezes, the movement of air form land to water, which occur when land is cooler than adjacent water surfaces.

The low temperatures this morning (below) shows temperatures dropping into the 30sF over Vancouver Island and southern BC, while the water temperatures were around 50F, and the a number of the marine stations reported mid to upper 40s.  As as result,  land breezes formed on both shores and then collided over the central Strait of Georgia, forcing rising motion and clouds.

This figures illustrates what is happening:

A similar, but weaker, situation occurred over northern Puget Sound, with low 40s over land and low 50s over water.

No land breeze clouds tomorrow...a wet weather system is approaching!

from Cliff Mass Weather and Climate Blog https://ift.tt/2PjTthW

Wet Week in the West and Snow Hits Washington State

Recent newspaper articles talk about a prediction for dry conditions in the western U.S. over the winter, but the atmosphere this week has other ideas. 

Today, a hurricane is moving through the southwest, a frontal system is hitting California, and a weaker system is moving through Washington State (see pic below).   It is hailing outside as write this.

Want to be really shocked?  It is snowing at Steven's Pass, where the temperature is 32F.  Don't believe me?  Check out the latest picture from the WSDOT cam there.

The WRF model forecast for cumulative precipitation over the next week (through 5 PM next Tuesday) is mighty soggy, with rain over the entire domain.  1-2 inches in part of Washington and previously dry Utah gets hammered with up to 5-10 inches in places.  Northern California is wet.  This rain event will be the end of most western U.S. fires.

As noted in the media, we just finished our "water year"-- which runs from October 1 through Sept 31 each year.  In some ways, this period is our natural precipitation period, since October 1 is roughly the start of the time when rain is significant around the Northwest.

Our recent water year (2017-2018) at Seattle was above normal by about 3-4 inches (see cumulative precipitation chart, light green is normal, dark green is cumulative amount above normal)

And  the previous water year (2016-2017) was even wetter than normal!

To put it mildly, we have not been in drought the past few years.

The extended forecast of dry conditions is heavily dependent on the projection of a weak to moderate El Nino for this winter, with low pressure offshore.

 However, the patterns of the last few weeks and the upcoming week are very different...in fact, very La Nina like.  A characteristic of La Nina winters is a ridge offshore, with northerly, cool unstable flow over our region.

The upper level pattern this afternoon shows an upper trough pushing over Washington.  In January we would be talking about lowland snow with such a pattern.

Another trough on Friday, and this will be a wet one

 High pressure builds offshore during he weekend and a very deep trough will bring cold temperatures into the southwest.

 And next Monday evening, the pattern continues, with weak disturbances over our region.

So forgot warm/dry conditions for the next week.  Showers and cool temperatures will reign over the Northwest, with more sun from Saturday onward.



from Cliff Mass Weather and Climate Blog https://ift.tt/2Nj4vCy

Wet Week in the West and Snow Hits Washington State

Recent newspaper articles talk about a prediction for dry conditions in the western U.S. over the winter, but the atmosphere this week has other ideas. 

Today, a hurricane is moving through the southwest, a frontal system is hitting California, and a weaker system is moving through Washington State (see pic below).   It is hailing outside as write this.

Want to be really shocked?  It is snowing at Steven's Pass, where the temperature is 32F.  Don't believe me?  Check out the latest picture from the WSDOT cam there.

The WRF model forecast for cumulative precipitation over the next week (through 5 PM next Tuesday) is mighty soggy, with rain over the entire domain.  1-2 inches in part of Washington and previously dry Utah gets hammered with up to 5-10 inches in places.  Northern California is wet.  This rain event will be the end of most western U.S. fires.

As noted in the media, we just finished our "water year"-- which runs from October 1 through Sept 31 each year.  In some ways, this period is our natural precipitation period, since October 1 is roughly the start of the time when rain is significant around the Northwest.

Our recent water year (2017-2018) at Seattle was above normal by about 3-4 inches (see cumulative precipitation chart, light green is normal, dark green is cumulative amount above normal)

And  the previous water year (2016-2017) was even wetter than normal!

To put it mildly, we have not been in drought the past few years.

The extended forecast of dry conditions is heavily dependent on the projection of a weak to moderate El Nino for this winter, with low pressure offshore.

 However, the patterns of the last few weeks and the upcoming week are very different...in fact, very La Nina like.  A characteristic of La Nina winters is a ridge offshore, with northerly, cool unstable flow over our region.

The upper level pattern this afternoon shows an upper trough pushing over Washington.  In January we would be talking about lowland snow with such a pattern.

Another trough on Friday, and this will be a wet one

 High pressure builds offshore during he weekend and a very deep trough will bring cold temperatures into the southwest.

 And next Monday evening, the pattern continues, with weak disturbances over our region.

So forgot warm/dry conditions for the next week.  Showers and cool temperatures will reign over the Northwest, with more sun from Saturday onward.



from Cliff Mass Weather and Climate Blog https://ift.tt/2Nj4vCy